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Geomorphological applications ofcosmogenic isotope analysis Hermione AP Cockburnab andMichael A SummerfieldaaInstitute of Geography University of Edinburgh Drummond Street EdinburghEH8 9XP UKbSchool of Earth Sciences University of Melbourne Victoria 3010 Australia
Abstract Cosmogenic isotope analysis involves the measurement of cosmogenic nuclides thathave accumulated in the upper few metres of the Earthrsquos surface as a result of interactionsbetween cosmic rays and target elements The concentrations of these cosmogenic nuclides canprovide quantitative estimates of the timing and rate of geomorphic processes In dating appli-cations the concentration of cosmogenic nuclides is interpreted as reflecting the time elapsedsince a surface exposure event However over most of the Earthrsquos surface for most of the timethe landsurface experiences incremental denudation and in these circumstances cosmogenicnuclide concentrations are related to the rate of denudation Applications of event dating usingcosmogenic isotopes include constructional landforms such as volcanic and depositionalfeatures fault displacement meteorite impacts rapid mass movement bedrock surfaces rapidlyeroded by fluvial or wave action or exposed by glacial retreat and the burial of sediment or iceStrategies for quantifying rates of incremental change include estimates of denudation ratesfrom site-specific samples and from fluvial sediment samples reflecting catchment-wide ratesand measurements of cosmogenic nuclide concentrations in soils and regolith to quantify ratesof rock weathering The past decade has seen a rapid growth in applications of cosmogenicisotope analysis to a wide range of geomorphological problems and the technique is nowplaying a major role in dating and quantifying rates of landscape change over timescales ofseveral thousands to several millions of years
Key words cosmogenic isotope analysis cosmogenic nuclides dating denudation ratesgeomorphology
Progress in Physical Geography 281 (2004) pp 1ndash42
copy Arnold 2004 1011910309133304pp395oa
Author for correspondence Tel 0131 650 2519 fax 0131 650 2524 e-mail masgeoedacuk
2 Geomorphological applications of cosmogenic isotope analysis
I Introduction
The Earth is under constant bombardment by cosmic radiation primarily comprisingprotons with a smaller proportion of a-particles electrons and heavier nuclei Aproportion of this cosmic radiation comes from the Sun but the more energetic particles(typically 108ndash1010 eV) originate largely from our own galaxy with the very highestenergy particles (up to 1020 eV) having a source outside the Milky Way It is the higherenergy particles that are primarily responsible for generating the shower of secondarycosmic radiation in the upper atmosphere which reaches the Earthrsquos surface Thissecondary cosmic radiation flux consisting predominantly of neutrons with a muchsmaller component of muons interacts with target elements in minerals in a shallowlayer at the Earthrsquos surface to produce in situ extremely small quantities of cosmogenicnuclides Measurements of the amounts of these cosmogenic nuclides accumulatedover time can provide valuable information on the age and rate of change of the landsurface
Until the development in the late 1970s and early 1980s of accelerator mass spec-trometry (AMS) (Klein et al 1982 Elmore and Phillips 1987) and high-sensitivity noblegas mass spectrometry cosmogenic isotope analysis was confined to the relativelymuch higher concentrations of cosmogenic nuclides found in meteorites and lunarsamples that had received a cosmic-ray flux which had not been attenuated by theshielding effects of the Earthrsquos atmosphere Nonetheless even prior to developing thecapability to measure the exceedingly low concentrations of cosmogenic nuclidesproduced in situ in terrestrial materials the potential for applying such measurementsto geomorphological problems was recognized In fact the origins of using cosmogenicnuclides to determine the exposure history of the Earthrsquos surface go back to Davis andSchaffer (1955) who used beta counting to date a late Quaternary surface on a chlorine-rich phonolite Other early contributions include a largely ignored paper published inGerman in the early 1970s (Froumlhlich and Luumlbert 1973) which proposed calculatingdenudation rates using in-situ-produced cosmogenic nuclides (see Tuniz et al 1998)and the work by Srinivasan (1976) who measured cosmogenic 126Xe to determine alsquosurface residence timersquo for a sedimentary barite sample (see Cerling and Craig 1994a)
Following the advances in measurement technology and the increased understand-ing of the in situ production of cosmogenic nuclides that was acquired during the 1980sthere has been a rapid growth in applications of cosmogenic isotope analysis in geo-morphology and related fields of Quaternary science From five or six papers per yearin the early 1990s the number has risen to 20 or more in the past two to three years(Figure 1) These totals are for applications papers only and exclude a large body oftheoretical and technical contributions
The importance of cosmogenic isotope analysis as a technique in geomorphologyarises in part from the timescale that it can address Depending on the local rate of landsurface stripping cosmogenic isotope analysis can provide information on ages ofgeomorphic events denudation rates and the operation of specific geomorphicprocesses over timescales ranging from thousands to millions of years It thus forms acrucial bridge between investigations over the short term based on modern process ratemeasurements and historical data and long-term studies based on techniques such asthermochronology (Burbank et al 1996 Cockburn et al 2000) A key advantage of atechnique that provides information on denudation over these intermediate timescales
HAP Cockburn and MA Summerfield 3
is that it can effectively average out short-term fluctuations in rates associated withclimatic variations or other high frequency perturbations It also circumvents to a largeextent the problem of high magnitudendashlow frequency events which severely limit thepotential to extrapolate short-term geomorphic process rate measurements (typicallylimited to a few years) to the longer term
Another key advantage is the very wide scope for sampling in addressing a diverserange of geomorphological problems Unlike information gleaned from geochronolog-ical techniques such as radiocarbon or luminescence dating which are frequentlyconfined to rather specific field situations cosmogenic isotope data can be acquiredfrom an enormous variety of geomorphologically useful contexts This is the casebecause of the almost ubiquitous occurrence in common rock-forming minerals of thetarget elements for cosmogenic nuclide production (Table 1) The ability to date orquantify rates of landform change directly rather than inferring chronologicalinformation about them indirectly makes the technique particularly valuable In shortcosmogenic isotope analysis enables geomorphological studies to be attempted thatwere previously impossible it can address key questions about geomorphic processrates and it provides the means to answer long-standing questions about landscapeevolution
In this review we focus on the geomorphological applications of in situ-producedcosmogenic isotope analysis although many of the studies discussed especially thoseinvolving the dating of landforms also have great relevance to problems in Quaternaryscience We exclude applications based on atmospheric (also known as lsquometeoricrsquo orlsquogarden varietyrsquo) cosmogenic nuclide production although this can also provideimportant insights into environmental processes (eg McKean et al 1993 Stanford etal 2000) not least in 14C dating of organic materials Our aim is to provide a compre-hensive although not exhaustive survey to inform researchers unfamiliar with thetechnique of the potential of in situ-produced cosmogenic isotope analysis in advancing
Figure 1 Growth in number of papers on geomorphological applica-tions of in situ-produced cosmogenic nuclides published from 1990 tomid-2002
4 Geomorphological applications of cosmogenic isotope analysis
Table 1
Prop
erties of the
main terrestrial c
osmog
enic nuc
lides used in
geo
morph
olog
ical app
lications
Isotop
eHalf-life (yr)
Main target
Measuremen
tCom
men
tsminerals
3 He
stab
leolivine pyrox
ene
mass
High prod
uctio
n rate w
hich
is relatively well c
onstrained
low
hornblen
de g
arne
tspec
trom
etry
detection lim
it lo
ng exp
osure histories ca
n be
recorde
d in suitable
host m
inerals which
retain
3 He but not for qua
rtz from
which
there
is gen
erally rap
id diffusion of 3He possible inhe
ritanc
e of 3He
whe
re sam
ple ha
s be
en previou
sly expo
sed Best results using
samples from
roc
ks w
ith crystallin
e ag
es lt5Ma
10Be
151
acute10
6qu
artz o
livine
AMS
Prim
ary target m
ineral (q
uartz) is w
idesprea
d can
be an
alysed
inco
njun
ction with
other cosmog
enic nuc
lides fo
rmed
in qua
rtz (26 A
lin sam
e aliquo
t 14C and
21 N
e in sam
e sample) lon
g ha
lf-life
prov
ides possibility of rec
ording
long
exp
osure histories lo
wprod
uctio
n rate m
eans app
lication is limite
d whe
re exp
osure even
tsare rece
nt relative ab
unda
nce of atm
osph
eric 10 B
e a po
tential
contam
inan
t req
uiring
rigorou
s sample trea
tmen
t prod
uctio
n rate
well-co
nstra
ined
only for qu
artz
14C
573
acute10
3qu
artz c
alcite
AMS
Target m
inerals are widesprea
d sho
rt half-life mea
ns th
at rec
ent
complex
exp
osure histories ca
n be
ana
lysed whe
n pa
ired
with
astab
le cosmog
enic nuc
lide or a cosmog
enic rad
ionu
clide with
along
er half-life sho
rt half-life also limits th
e po
tential for in
heritanc
epo
ssibility of co
ntam
ination by
atm
osph
eric 1
4 C p
roce
dures
curren
tly le
ast d
evelop
ed of the
com
mon
ly used co
smog
enic
nuclides
HAP Cockburn and MA Summerfield 5
21Ne
stab
lequ
artz o
livine
mass
Target m
inerals are widespread poten
tial for rec
ording
the long
est
garnet
spec
trom
etry
expo
sure histories of a
ny cosmog
enic isotop
e as it is stab
le and
clinop
yrox
ene
unlik
e 3 H
e app
ears to
be effectively retained
in qua
rtz how
ever
this also means th
at in
heritanc
e from
previou
s expo
sure is possible
even
ove
r long
time span
s as a stab
le nuc
lide it is valua
ble whe
nan
alysed
in con
junc
tion with
10 B
e an
d 26Al to reco
rd com
plex
expo
sure histories c
areful correction for nu
cleo
genic
21Ne is
requ
ired
espec
ially
for sho
rt exp
osure histories in sam
ples w
ith old
crystalliza
tion ages an
d trap
ped
21Ne in in
clusions
26Al
720
acute10
5qu
artz
AMS
Target m
ineral is
widesprea
d can
be an
alysed
in con
junc
tion with
othe
r co
smog
enic nuc
lides fo
rmed
in qua
rtz (10 B
e 14 C
21 N
e) in
same aliquo
tsam
ple to in
vestigate co
mplex
exp
osure histories very
low con
centratio
n (lt20
0pp
m) of to
tal A
l in sam
ple requ
ired
as it is
difficu
lt to m
easure lo
w 26 A
l27 A
l ratios by
AMS
36Cl
301
acute10
5K-feldspa
rAMS
Atm
osph
eric produ
ction is lo
w so can be
used on
who
le roc
k (eg
plag
ioclase
basalt an
d lim
estone
) on
ly viable co
smog
enic nuc
lide for some
calcite
35 C
l in
litho
logies multip
le produ
ction pa
thway
s from
multip
le
fluid in
clusions
elem
ents tog
ethe
r with
rad
ioge
nic an
d nu
cleo
genic prod
uctio
nin qua
rtz
mea
n that anc
illary ge
oche
mical ana
lyses are requ
ired
and
that data
analysis is
more co
mplex
than
for othe
r co
smog
enic nuc
lides sulfur
contam
ination in sam
ples is typ
ical and
discrim
ination be
twee
n 36Cl
and the isob
ar 36 S by AMS ge
nerally
req
uires the high
er ene
rgies
prov
ided
by high
voltage
acc
elerators
Source
ba
sed on
Kurz an
d Brook
(199
4) Tun
iz eta
l (199
8) F
ifield (199
9) and
Gosse and
Phillips (2
001)
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
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Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
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Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
2 Geomorphological applications of cosmogenic isotope analysis
I Introduction
The Earth is under constant bombardment by cosmic radiation primarily comprisingprotons with a smaller proportion of a-particles electrons and heavier nuclei Aproportion of this cosmic radiation comes from the Sun but the more energetic particles(typically 108ndash1010 eV) originate largely from our own galaxy with the very highestenergy particles (up to 1020 eV) having a source outside the Milky Way It is the higherenergy particles that are primarily responsible for generating the shower of secondarycosmic radiation in the upper atmosphere which reaches the Earthrsquos surface Thissecondary cosmic radiation flux consisting predominantly of neutrons with a muchsmaller component of muons interacts with target elements in minerals in a shallowlayer at the Earthrsquos surface to produce in situ extremely small quantities of cosmogenicnuclides Measurements of the amounts of these cosmogenic nuclides accumulatedover time can provide valuable information on the age and rate of change of the landsurface
Until the development in the late 1970s and early 1980s of accelerator mass spec-trometry (AMS) (Klein et al 1982 Elmore and Phillips 1987) and high-sensitivity noblegas mass spectrometry cosmogenic isotope analysis was confined to the relativelymuch higher concentrations of cosmogenic nuclides found in meteorites and lunarsamples that had received a cosmic-ray flux which had not been attenuated by theshielding effects of the Earthrsquos atmosphere Nonetheless even prior to developing thecapability to measure the exceedingly low concentrations of cosmogenic nuclidesproduced in situ in terrestrial materials the potential for applying such measurementsto geomorphological problems was recognized In fact the origins of using cosmogenicnuclides to determine the exposure history of the Earthrsquos surface go back to Davis andSchaffer (1955) who used beta counting to date a late Quaternary surface on a chlorine-rich phonolite Other early contributions include a largely ignored paper published inGerman in the early 1970s (Froumlhlich and Luumlbert 1973) which proposed calculatingdenudation rates using in-situ-produced cosmogenic nuclides (see Tuniz et al 1998)and the work by Srinivasan (1976) who measured cosmogenic 126Xe to determine alsquosurface residence timersquo for a sedimentary barite sample (see Cerling and Craig 1994a)
Following the advances in measurement technology and the increased understand-ing of the in situ production of cosmogenic nuclides that was acquired during the 1980sthere has been a rapid growth in applications of cosmogenic isotope analysis in geo-morphology and related fields of Quaternary science From five or six papers per yearin the early 1990s the number has risen to 20 or more in the past two to three years(Figure 1) These totals are for applications papers only and exclude a large body oftheoretical and technical contributions
The importance of cosmogenic isotope analysis as a technique in geomorphologyarises in part from the timescale that it can address Depending on the local rate of landsurface stripping cosmogenic isotope analysis can provide information on ages ofgeomorphic events denudation rates and the operation of specific geomorphicprocesses over timescales ranging from thousands to millions of years It thus forms acrucial bridge between investigations over the short term based on modern process ratemeasurements and historical data and long-term studies based on techniques such asthermochronology (Burbank et al 1996 Cockburn et al 2000) A key advantage of atechnique that provides information on denudation over these intermediate timescales
HAP Cockburn and MA Summerfield 3
is that it can effectively average out short-term fluctuations in rates associated withclimatic variations or other high frequency perturbations It also circumvents to a largeextent the problem of high magnitudendashlow frequency events which severely limit thepotential to extrapolate short-term geomorphic process rate measurements (typicallylimited to a few years) to the longer term
Another key advantage is the very wide scope for sampling in addressing a diverserange of geomorphological problems Unlike information gleaned from geochronolog-ical techniques such as radiocarbon or luminescence dating which are frequentlyconfined to rather specific field situations cosmogenic isotope data can be acquiredfrom an enormous variety of geomorphologically useful contexts This is the casebecause of the almost ubiquitous occurrence in common rock-forming minerals of thetarget elements for cosmogenic nuclide production (Table 1) The ability to date orquantify rates of landform change directly rather than inferring chronologicalinformation about them indirectly makes the technique particularly valuable In shortcosmogenic isotope analysis enables geomorphological studies to be attempted thatwere previously impossible it can address key questions about geomorphic processrates and it provides the means to answer long-standing questions about landscapeevolution
In this review we focus on the geomorphological applications of in situ-producedcosmogenic isotope analysis although many of the studies discussed especially thoseinvolving the dating of landforms also have great relevance to problems in Quaternaryscience We exclude applications based on atmospheric (also known as lsquometeoricrsquo orlsquogarden varietyrsquo) cosmogenic nuclide production although this can also provideimportant insights into environmental processes (eg McKean et al 1993 Stanford etal 2000) not least in 14C dating of organic materials Our aim is to provide a compre-hensive although not exhaustive survey to inform researchers unfamiliar with thetechnique of the potential of in situ-produced cosmogenic isotope analysis in advancing
Figure 1 Growth in number of papers on geomorphological applica-tions of in situ-produced cosmogenic nuclides published from 1990 tomid-2002
4 Geomorphological applications of cosmogenic isotope analysis
Table 1
Prop
erties of the
main terrestrial c
osmog
enic nuc
lides used in
geo
morph
olog
ical app
lications
Isotop
eHalf-life (yr)
Main target
Measuremen
tCom
men
tsminerals
3 He
stab
leolivine pyrox
ene
mass
High prod
uctio
n rate w
hich
is relatively well c
onstrained
low
hornblen
de g
arne
tspec
trom
etry
detection lim
it lo
ng exp
osure histories ca
n be
recorde
d in suitable
host m
inerals which
retain
3 He but not for qua
rtz from
which
there
is gen
erally rap
id diffusion of 3He possible inhe
ritanc
e of 3He
whe
re sam
ple ha
s be
en previou
sly expo
sed Best results using
samples from
roc
ks w
ith crystallin
e ag
es lt5Ma
10Be
151
acute10
6qu
artz o
livine
AMS
Prim
ary target m
ineral (q
uartz) is w
idesprea
d can
be an
alysed
inco
njun
ction with
other cosmog
enic nuc
lides fo
rmed
in qua
rtz (26 A
lin sam
e aliquo
t 14C and
21 N
e in sam
e sample) lon
g ha
lf-life
prov
ides possibility of rec
ording
long
exp
osure histories lo
wprod
uctio
n rate m
eans app
lication is limite
d whe
re exp
osure even
tsare rece
nt relative ab
unda
nce of atm
osph
eric 10 B
e a po
tential
contam
inan
t req
uiring
rigorou
s sample trea
tmen
t prod
uctio
n rate
well-co
nstra
ined
only for qu
artz
14C
573
acute10
3qu
artz c
alcite
AMS
Target m
inerals are widesprea
d sho
rt half-life mea
ns th
at rec
ent
complex
exp
osure histories ca
n be
ana
lysed whe
n pa
ired
with
astab
le cosmog
enic nuc
lide or a cosmog
enic rad
ionu
clide with
along
er half-life sho
rt half-life also limits th
e po
tential for in
heritanc
epo
ssibility of co
ntam
ination by
atm
osph
eric 1
4 C p
roce
dures
curren
tly le
ast d
evelop
ed of the
com
mon
ly used co
smog
enic
nuclides
HAP Cockburn and MA Summerfield 5
21Ne
stab
lequ
artz o
livine
mass
Target m
inerals are widespread poten
tial for rec
ording
the long
est
garnet
spec
trom
etry
expo
sure histories of a
ny cosmog
enic isotop
e as it is stab
le and
clinop
yrox
ene
unlik
e 3 H
e app
ears to
be effectively retained
in qua
rtz how
ever
this also means th
at in
heritanc
e from
previou
s expo
sure is possible
even
ove
r long
time span
s as a stab
le nuc
lide it is valua
ble whe
nan
alysed
in con
junc
tion with
10 B
e an
d 26Al to reco
rd com
plex
expo
sure histories c
areful correction for nu
cleo
genic
21Ne is
requ
ired
espec
ially
for sho
rt exp
osure histories in sam
ples w
ith old
crystalliza
tion ages an
d trap
ped
21Ne in in
clusions
26Al
720
acute10
5qu
artz
AMS
Target m
ineral is
widesprea
d can
be an
alysed
in con
junc
tion with
othe
r co
smog
enic nuc
lides fo
rmed
in qua
rtz (10 B
e 14 C
21 N
e) in
same aliquo
tsam
ple to in
vestigate co
mplex
exp
osure histories very
low con
centratio
n (lt20
0pp
m) of to
tal A
l in sam
ple requ
ired
as it is
difficu
lt to m
easure lo
w 26 A
l27 A
l ratios by
AMS
36Cl
301
acute10
5K-feldspa
rAMS
Atm
osph
eric produ
ction is lo
w so can be
used on
who
le roc
k (eg
plag
ioclase
basalt an
d lim
estone
) on
ly viable co
smog
enic nuc
lide for some
calcite
35 C
l in
litho
logies multip
le produ
ction pa
thway
s from
multip
le
fluid in
clusions
elem
ents tog
ethe
r with
rad
ioge
nic an
d nu
cleo
genic prod
uctio
nin qua
rtz
mea
n that anc
illary ge
oche
mical ana
lyses are requ
ired
and
that data
analysis is
more co
mplex
than
for othe
r co
smog
enic nuc
lides sulfur
contam
ination in sam
ples is typ
ical and
discrim
ination be
twee
n 36Cl
and the isob
ar 36 S by AMS ge
nerally
req
uires the high
er ene
rgies
prov
ided
by high
voltage
acc
elerators
Source
ba
sed on
Kurz an
d Brook
(199
4) Tun
iz eta
l (199
8) F
ifield (199
9) and
Gosse and
Phillips (2
001)
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
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Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
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Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 3
is that it can effectively average out short-term fluctuations in rates associated withclimatic variations or other high frequency perturbations It also circumvents to a largeextent the problem of high magnitudendashlow frequency events which severely limit thepotential to extrapolate short-term geomorphic process rate measurements (typicallylimited to a few years) to the longer term
Another key advantage is the very wide scope for sampling in addressing a diverserange of geomorphological problems Unlike information gleaned from geochronolog-ical techniques such as radiocarbon or luminescence dating which are frequentlyconfined to rather specific field situations cosmogenic isotope data can be acquiredfrom an enormous variety of geomorphologically useful contexts This is the casebecause of the almost ubiquitous occurrence in common rock-forming minerals of thetarget elements for cosmogenic nuclide production (Table 1) The ability to date orquantify rates of landform change directly rather than inferring chronologicalinformation about them indirectly makes the technique particularly valuable In shortcosmogenic isotope analysis enables geomorphological studies to be attempted thatwere previously impossible it can address key questions about geomorphic processrates and it provides the means to answer long-standing questions about landscapeevolution
In this review we focus on the geomorphological applications of in situ-producedcosmogenic isotope analysis although many of the studies discussed especially thoseinvolving the dating of landforms also have great relevance to problems in Quaternaryscience We exclude applications based on atmospheric (also known as lsquometeoricrsquo orlsquogarden varietyrsquo) cosmogenic nuclide production although this can also provideimportant insights into environmental processes (eg McKean et al 1993 Stanford etal 2000) not least in 14C dating of organic materials Our aim is to provide a compre-hensive although not exhaustive survey to inform researchers unfamiliar with thetechnique of the potential of in situ-produced cosmogenic isotope analysis in advancing
Figure 1 Growth in number of papers on geomorphological applica-tions of in situ-produced cosmogenic nuclides published from 1990 tomid-2002
4 Geomorphological applications of cosmogenic isotope analysis
Table 1
Prop
erties of the
main terrestrial c
osmog
enic nuc
lides used in
geo
morph
olog
ical app
lications
Isotop
eHalf-life (yr)
Main target
Measuremen
tCom
men
tsminerals
3 He
stab
leolivine pyrox
ene
mass
High prod
uctio
n rate w
hich
is relatively well c
onstrained
low
hornblen
de g
arne
tspec
trom
etry
detection lim
it lo
ng exp
osure histories ca
n be
recorde
d in suitable
host m
inerals which
retain
3 He but not for qua
rtz from
which
there
is gen
erally rap
id diffusion of 3He possible inhe
ritanc
e of 3He
whe
re sam
ple ha
s be
en previou
sly expo
sed Best results using
samples from
roc
ks w
ith crystallin
e ag
es lt5Ma
10Be
151
acute10
6qu
artz o
livine
AMS
Prim
ary target m
ineral (q
uartz) is w
idesprea
d can
be an
alysed
inco
njun
ction with
other cosmog
enic nuc
lides fo
rmed
in qua
rtz (26 A
lin sam
e aliquo
t 14C and
21 N
e in sam
e sample) lon
g ha
lf-life
prov
ides possibility of rec
ording
long
exp
osure histories lo
wprod
uctio
n rate m
eans app
lication is limite
d whe
re exp
osure even
tsare rece
nt relative ab
unda
nce of atm
osph
eric 10 B
e a po
tential
contam
inan
t req
uiring
rigorou
s sample trea
tmen
t prod
uctio
n rate
well-co
nstra
ined
only for qu
artz
14C
573
acute10
3qu
artz c
alcite
AMS
Target m
inerals are widesprea
d sho
rt half-life mea
ns th
at rec
ent
complex
exp
osure histories ca
n be
ana
lysed whe
n pa
ired
with
astab
le cosmog
enic nuc
lide or a cosmog
enic rad
ionu
clide with
along
er half-life sho
rt half-life also limits th
e po
tential for in
heritanc
epo
ssibility of co
ntam
ination by
atm
osph
eric 1
4 C p
roce
dures
curren
tly le
ast d
evelop
ed of the
com
mon
ly used co
smog
enic
nuclides
HAP Cockburn and MA Summerfield 5
21Ne
stab
lequ
artz o
livine
mass
Target m
inerals are widespread poten
tial for rec
ording
the long
est
garnet
spec
trom
etry
expo
sure histories of a
ny cosmog
enic isotop
e as it is stab
le and
clinop
yrox
ene
unlik
e 3 H
e app
ears to
be effectively retained
in qua
rtz how
ever
this also means th
at in
heritanc
e from
previou
s expo
sure is possible
even
ove
r long
time span
s as a stab
le nuc
lide it is valua
ble whe
nan
alysed
in con
junc
tion with
10 B
e an
d 26Al to reco
rd com
plex
expo
sure histories c
areful correction for nu
cleo
genic
21Ne is
requ
ired
espec
ially
for sho
rt exp
osure histories in sam
ples w
ith old
crystalliza
tion ages an
d trap
ped
21Ne in in
clusions
26Al
720
acute10
5qu
artz
AMS
Target m
ineral is
widesprea
d can
be an
alysed
in con
junc
tion with
othe
r co
smog
enic nuc
lides fo
rmed
in qua
rtz (10 B
e 14 C
21 N
e) in
same aliquo
tsam
ple to in
vestigate co
mplex
exp
osure histories very
low con
centratio
n (lt20
0pp
m) of to
tal A
l in sam
ple requ
ired
as it is
difficu
lt to m
easure lo
w 26 A
l27 A
l ratios by
AMS
36Cl
301
acute10
5K-feldspa
rAMS
Atm
osph
eric produ
ction is lo
w so can be
used on
who
le roc
k (eg
plag
ioclase
basalt an
d lim
estone
) on
ly viable co
smog
enic nuc
lide for some
calcite
35 C
l in
litho
logies multip
le produ
ction pa
thway
s from
multip
le
fluid in
clusions
elem
ents tog
ethe
r with
rad
ioge
nic an
d nu
cleo
genic prod
uctio
nin qua
rtz
mea
n that anc
illary ge
oche
mical ana
lyses are requ
ired
and
that data
analysis is
more co
mplex
than
for othe
r co
smog
enic nuc
lides sulfur
contam
ination in sam
ples is typ
ical and
discrim
ination be
twee
n 36Cl
and the isob
ar 36 S by AMS ge
nerally
req
uires the high
er ene
rgies
prov
ided
by high
voltage
acc
elerators
Source
ba
sed on
Kurz an
d Brook
(199
4) Tun
iz eta
l (199
8) F
ifield (199
9) and
Gosse and
Phillips (2
001)
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
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Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
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Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
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32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
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J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
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Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
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Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
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Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
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Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
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Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
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Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
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Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
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Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
4 Geomorphological applications of cosmogenic isotope analysis
Table 1
Prop
erties of the
main terrestrial c
osmog
enic nuc
lides used in
geo
morph
olog
ical app
lications
Isotop
eHalf-life (yr)
Main target
Measuremen
tCom
men
tsminerals
3 He
stab
leolivine pyrox
ene
mass
High prod
uctio
n rate w
hich
is relatively well c
onstrained
low
hornblen
de g
arne
tspec
trom
etry
detection lim
it lo
ng exp
osure histories ca
n be
recorde
d in suitable
host m
inerals which
retain
3 He but not for qua
rtz from
which
there
is gen
erally rap
id diffusion of 3He possible inhe
ritanc
e of 3He
whe
re sam
ple ha
s be
en previou
sly expo
sed Best results using
samples from
roc
ks w
ith crystallin
e ag
es lt5Ma
10Be
151
acute10
6qu
artz o
livine
AMS
Prim
ary target m
ineral (q
uartz) is w
idesprea
d can
be an
alysed
inco
njun
ction with
other cosmog
enic nuc
lides fo
rmed
in qua
rtz (26 A
lin sam
e aliquo
t 14C and
21 N
e in sam
e sample) lon
g ha
lf-life
prov
ides possibility of rec
ording
long
exp
osure histories lo
wprod
uctio
n rate m
eans app
lication is limite
d whe
re exp
osure even
tsare rece
nt relative ab
unda
nce of atm
osph
eric 10 B
e a po
tential
contam
inan
t req
uiring
rigorou
s sample trea
tmen
t prod
uctio
n rate
well-co
nstra
ined
only for qu
artz
14C
573
acute10
3qu
artz c
alcite
AMS
Target m
inerals are widesprea
d sho
rt half-life mea
ns th
at rec
ent
complex
exp
osure histories ca
n be
ana
lysed whe
n pa
ired
with
astab
le cosmog
enic nuc
lide or a cosmog
enic rad
ionu
clide with
along
er half-life sho
rt half-life also limits th
e po
tential for in
heritanc
epo
ssibility of co
ntam
ination by
atm
osph
eric 1
4 C p
roce
dures
curren
tly le
ast d
evelop
ed of the
com
mon
ly used co
smog
enic
nuclides
HAP Cockburn and MA Summerfield 5
21Ne
stab
lequ
artz o
livine
mass
Target m
inerals are widespread poten
tial for rec
ording
the long
est
garnet
spec
trom
etry
expo
sure histories of a
ny cosmog
enic isotop
e as it is stab
le and
clinop
yrox
ene
unlik
e 3 H
e app
ears to
be effectively retained
in qua
rtz how
ever
this also means th
at in
heritanc
e from
previou
s expo
sure is possible
even
ove
r long
time span
s as a stab
le nuc
lide it is valua
ble whe
nan
alysed
in con
junc
tion with
10 B
e an
d 26Al to reco
rd com
plex
expo
sure histories c
areful correction for nu
cleo
genic
21Ne is
requ
ired
espec
ially
for sho
rt exp
osure histories in sam
ples w
ith old
crystalliza
tion ages an
d trap
ped
21Ne in in
clusions
26Al
720
acute10
5qu
artz
AMS
Target m
ineral is
widesprea
d can
be an
alysed
in con
junc
tion with
othe
r co
smog
enic nuc
lides fo
rmed
in qua
rtz (10 B
e 14 C
21 N
e) in
same aliquo
tsam
ple to in
vestigate co
mplex
exp
osure histories very
low con
centratio
n (lt20
0pp
m) of to
tal A
l in sam
ple requ
ired
as it is
difficu
lt to m
easure lo
w 26 A
l27 A
l ratios by
AMS
36Cl
301
acute10
5K-feldspa
rAMS
Atm
osph
eric produ
ction is lo
w so can be
used on
who
le roc
k (eg
plag
ioclase
basalt an
d lim
estone
) on
ly viable co
smog
enic nuc
lide for some
calcite
35 C
l in
litho
logies multip
le produ
ction pa
thway
s from
multip
le
fluid in
clusions
elem
ents tog
ethe
r with
rad
ioge
nic an
d nu
cleo
genic prod
uctio
nin qua
rtz
mea
n that anc
illary ge
oche
mical ana
lyses are requ
ired
and
that data
analysis is
more co
mplex
than
for othe
r co
smog
enic nuc
lides sulfur
contam
ination in sam
ples is typ
ical and
discrim
ination be
twee
n 36Cl
and the isob
ar 36 S by AMS ge
nerally
req
uires the high
er ene
rgies
prov
ided
by high
voltage
acc
elerators
Source
ba
sed on
Kurz an
d Brook
(199
4) Tun
iz eta
l (199
8) F
ifield (199
9) and
Gosse and
Phillips (2
001)
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 5
21Ne
stab
lequ
artz o
livine
mass
Target m
inerals are widespread poten
tial for rec
ording
the long
est
garnet
spec
trom
etry
expo
sure histories of a
ny cosmog
enic isotop
e as it is stab
le and
clinop
yrox
ene
unlik
e 3 H
e app
ears to
be effectively retained
in qua
rtz how
ever
this also means th
at in
heritanc
e from
previou
s expo
sure is possible
even
ove
r long
time span
s as a stab
le nuc
lide it is valua
ble whe
nan
alysed
in con
junc
tion with
10 B
e an
d 26Al to reco
rd com
plex
expo
sure histories c
areful correction for nu
cleo
genic
21Ne is
requ
ired
espec
ially
for sho
rt exp
osure histories in sam
ples w
ith old
crystalliza
tion ages an
d trap
ped
21Ne in in
clusions
26Al
720
acute10
5qu
artz
AMS
Target m
ineral is
widesprea
d can
be an
alysed
in con
junc
tion with
othe
r co
smog
enic nuc
lides fo
rmed
in qua
rtz (10 B
e 14 C
21 N
e) in
same aliquo
tsam
ple to in
vestigate co
mplex
exp
osure histories very
low con
centratio
n (lt20
0pp
m) of to
tal A
l in sam
ple requ
ired
as it is
difficu
lt to m
easure lo
w 26 A
l27 A
l ratios by
AMS
36Cl
301
acute10
5K-feldspa
rAMS
Atm
osph
eric produ
ction is lo
w so can be
used on
who
le roc
k (eg
plag
ioclase
basalt an
d lim
estone
) on
ly viable co
smog
enic nuc
lide for some
calcite
35 C
l in
litho
logies multip
le produ
ction pa
thway
s from
multip
le
fluid in
clusions
elem
ents tog
ethe
r with
rad
ioge
nic an
d nu
cleo
genic prod
uctio
nin qua
rtz
mea
n that anc
illary ge
oche
mical ana
lyses are requ
ired
and
that data
analysis is
more co
mplex
than
for othe
r co
smog
enic nuc
lides sulfur
contam
ination in sam
ples is typ
ical and
discrim
ination be
twee
n 36Cl
and the isob
ar 36 S by AMS ge
nerally
req
uires the high
er ene
rgies
prov
ided
by high
voltage
acc
elerators
Source
ba
sed on
Kurz an
d Brook
(199
4) Tun
iz eta
l (199
8) F
ifield (199
9) and
Gosse and
Phillips (2
001)
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
6 Geomorphological applications of cosmogenic isotope analysis
research in geomorphology and allied fields Several excellent discussions of theprinciples and technical details of cosmogenic isotope analysis are already availablemost notably the comprehensive review by Gosse and Phillips (2001) but alsoincluding contributions by Lal and Peters (1967) Lal (1988) Nishiizumi et al (1993)Finkel and Suter (1993) Cerling and Craig (1994a) Bierman (1994) Kurz and Brook(1994) Tuniz et al (1998) Fifield (1999) and Zreda and Phillips (2000) Discussions ofcosmogenic isotope analysis are now also to be found in texts and reference manuals(eg Dickin 1995 Noller et al 2000) an indication that the technique is beginning tomove from the purely development stage to more routine applications
II Cosmogenic isotope analysis
The main principles that govern the use of cosmogenic isotopes in geomorphology areconceptually simple a cascade of cosmic radiation continuously bombards the Earth ofwhich a small proportion reaches the surface where nuclear interactions with terrestrialmaterials such as soil or rock produce cosmogenic nuclides Strong attenuation of thecosmic-ray flux restricts production to the upper few metres of the Earthrsquos crust thusthe concentration of in situ-produced cosmogenic nuclides in a surface sample providesa quantitative record of near-surface exposure Lal (1988) identified 12 cosmogenicisotopes that are produced in terrestrial materials Six of these have been significant ingeomorphological investigations ndash 3He 10Be 14C 21Ne 26Al 36Cl (Table 1) ndash whereasothers such as 39Ar and 41Ca (eg Loosli 1983 Fink et al 1990) will require furtherdevelopment for geomorphological applications
Knowledge of production mechanisms and time-integrated production rates formthe basis for the application of cosmogenic isotope analysis in geomorphologySignificant advances have been made since the pioneering work of Lal and Peters(1967) and reducing remaining uncertainties in production systematics remains a majorresearch priority (Gosse et al 1996 Dunai 2000 2001a b 2002 Stone 2000 2002Desilets et al 2001) Three principal mechanisms produce most cosmogenic nuclidesneutron spallation (the dominant process at the surface for all cosmogenic nuclides)thermal neutron capture and muonic interactions (which become of increasing relativeimportance with depth owing to the longer penetration lengths of these particles(Heisinger et al 2002a b) ) Production rates have been determined both empiricallyusing natural and artificial targets (eg Nishiizumi et al 1989 1996 Cerling and Craig1994b Niedermann et al 1994 Kubik et al 1998 Stone et al 1998a Dunai andWijbrans 2000) and theoretically (eg Lal 1991 Masarik and Reedy 1995 Masarik2002 see also Gosse and Phillips 2001 1519) Production rates vary with location andtime and must be scaled to account for a number of factors including depth within atarget (Lal 1991 Brown et al 1992) altitude (atmospheric shielding) and latitude(primarily the spatial influence of the geomagnetic field) (Lal 1991 Dunai 2000 Stone2000) topographic shielding and sample surface slope (exposure geometry) (Dunne etal 1999) Temporal influences that need to be addressed include variations in thecosmic-ray flux (Gosse and Phillips 2001) several geomagnetic field parametres thatvary with time (Kurz et al 1990 Licciardi et al 1999 Dunai 2001b Masarik et al 2001)intermittent shielding by surface materials including regolith sediments snow andvegetation (Nishiizumi et al 1989 Gosse et al 1995a) loss of cosmogenic nuclides
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
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Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
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Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
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3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 7
through diffusion from the host mineral (Trull et al 1991 Brook et al 1993) the effectsof fire (Bierman and Gillespie 1991 Zimmerman et al 1994) and possible changes inthe elevation of sampled sites (Lal 1991 Brown et al 1991) The net result of all theseeffects is that very careful sampling protocols are required based on a detailed under-standing of the geomorphic processes operating at sampled sites (Gosse and Phillips2001) and quantitative modelling of production rates for each isotope and application(Lal 1991 Dunai 2000 Stone 2000) Current levels of uncertainty are approximately10ndash20 most of which results from production rate scaling for latitude and altitude(see Gosse and Phillips 2001 for detailed discussion)
Cosmogenic nuclides accumulate in surface rocks as a function of production overtime moderated by denudation and for radioisotopes radioactive decay In some casesrelative concentrations in a suite of samples can be enough to solve a geomorphologi-cal problem More often translating measured abundances of cosmogenic nuclides intouseful geomorphic data depends on the use of a suitable interpretative model based onan appreciation of probable site history Various models have been devised some beingunique to individual applications The simplest and most widely used model involvesestimating the surface exposure age of a sample assuming that it has been suddenlyexposed from a depth sufficient for it not to contain a pre-existing (inherited)cosmogenic nuclide component and that it has not subsequently experienceddenudation or burial Under these circumstances a stable nuclide will continue toaccumulate indefinitely and therefore have no theoretical upper age limit although thezero denudation assumption is likely to be violated over longer timescales (~gt105 yr)and this imposes an upper limit to exposure dating Radionuclides eventually attain anequilibrium concentration where production is balanced by radioactive decay Thispoint defines the theoretical upper age limit for cosmogenic radionuclide exposuredating assuming zero denudation and is reached after approximately four times thehalf-life of the radionuclide being used (Table 1) If the assumption of zero denudationis not met or the nuclide concentration has become saturated the model will yield anlsquoapparentrsquo or minimum age In cases where there has been progressive denudationrather than a sudden lsquoexposure eventrsquo the cosmogenic nuclide concentration can beused to estimate a rate of denudation assuming that the system is in secular equilibriumwith respect to production denudation and decay (for radionuclides) (see Section V 1)This model effectively quantifies the lsquodwell timersquo of the upper 1ndash2 m of the surfaceSuch estimates are model-dependent since assumptions have to be made about secularequilibrium and the temporal variability in the denudation rate and are model maximaif these assumptions are not met (Bierman 1994 Cerling and Craig 1994a)
III Range of applications
In summarizing here the wide range of applications of cosmogenic isotope analysis togeomorphological phenomena it is important to highlight the two ways of modellingcosmogenic nuclide concentrations by drawing a distinction between dating geomor-phological lsquoeventsrsquo and measuring incremental change A geomorphological event inthis context is a change in the landscape that in relation to the background rate of mod-ification of the landscape represents an lsquoinstantaneousrsquo occurrence of sufficientmagnitude to expose material that has previously been effectively shielded from cosmic
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
8 Geomorphological applications of cosmogenic isotope analysis
radiation Common examples would be exposure of a fresh bedrock face by a deeplandslide or by glacial retreat Obviously once the lsquoeventrsquo has occurred lsquonormalrsquogeomorphic processes can lead to progressive denudation of the lsquoevent surfacersquo Thedepth of such modification and therefore the effect on cosmogenic nuclide concentra-tion is likely to be negligible in most instances for young events (typically ~1ndash3 acute104 yr) in comparison with the depth through which significant cosmogenic nuclideproduction occurs
By incremental change we envisage the mode of landscape activity that occurs overmost of the Earthrsquos landscape for most of the time ndash that is the progressive weatheringand stripping away of material in increments that are small in comparison with thecharacteristic attenuation length (typically ~06 m for rock) of cosmogenic nuclideproduction in Earth surface materials Although there are important exceptions it isusually more appropriate to regard the cosmogenic nuclide concentration of a sampleas reflecting the net effect of cosmogenic nuclide production and the prevailing rate ofdenudation (and radioactive decay in the case of radionuclides) than to think of a landsurface as having been initiated at a specific instance in the past and thereby seeing thelandscape as comprising elements with specific lsquoagesrsquo We prefer the term lsquodenudationrsquoto lsquoerosionrsquo when referring to the overall removal of surface materials resulting from acombination of processes or where the specific processes are undefined we uselsquoerosionrsquo where the process is predominantly or solely one of entrainment and transportof solid material by water ice or wind The distinction between dating events andrecording rates of incremental change has been used as the basis for organizing thisreview (Table 2)
IV Dating events
1 Constructional landforms
a Volcanic landforms The construction of new surfaces on volcanic landformswhich normally occurs lsquoinstantaneouslyrsquo in the context of long-term rates of landscapechange provides a clear example of a geomorphic event that can be dated through theaccumulation of cosmogenic nuclides Moreover the ability to date volcanic rocks inde-pendently using radiometric techniques has provided an important means ofdetermining cosmogenic nuclide production rates (Craig and Poreda 1986 Kurz 1986a1986b 1987 Phillips et al 1986 Marti and Craig 1987 Kurz et al 1990 Nishiizumi etal 1990 Poreda and Cerling 1992 Laughlin et al 1994) With these improvedcosmogenic nuclide production rate data surface exposure dating of lava flows is nowable to provide independent corroboration of radiometric ages where post-eruptivedenudation has been insignificant (Staudacher and Allegravegre 1993) and has the potentialto be used in preference to conventional radiometric methods in specific casesespecially for young flows and for samples with a low potassium content or inheritedargon (Sarda et al 1993 Zreda et al 1993 Laughlin et al 1994 Shepard et al 1995)
Where there are reliable radiometric ages for lava flows the difference in radiometricand apparent surface exposure age can be used to identify burial events and quantifythe rate of post-eruptive denudation (Cerling 1990) For instance on ReacuteunionStaudacher and Allegravegre (1993) found that the cosmogenic exposure age of ~62 plusmn 4 ka fora lava flow was only slightly younger than its 65 ka K-Ar age thus constraining the rate
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
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Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
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Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
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Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
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32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
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Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
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Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
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Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 9
Table 2
Applications
of in situ-pr
oduced cosmog
enic nuc
lides in
geo
morph
olog
y
Nature of
Categ
ory of
App
lications w
ith examples
proc
ess
proc
ess
Even
tCon
struction of
1 V
olca
nic
land
form
s(eg lava
flow
s cinde
r co
nes) d
ating of extrusive
roc
ks c
hron
olog
y of
(age
)land
surfaces
construc
tion of volca
nic land
form
svo
lcan
icCraig and
Pored
a (198
6) K
urz (198
6b 1
987) P
hillips eta
l (198
6) M
arti an
d Craig (1
987) C
erlin
g(199
0) N
ishiizum
i eta
l (199
0) K
urz et
al (19
90) Po
reda
and
Cerlin
g (199
2) A
ntho
ny and
Poths
(199
2) S
taud
ache
r an
d Allegrave
gre (199
3) S
arda
eta
l (199
3) Z
reda
eta
l (199
3) L
augh
lin eta
l (199
4)
Shep
ard et
al (19
95) Rey
nolds et
al (19
95) Ep
pes an
d Harrison (199
9) L
icciardi eta
l (199
9) F
enton
etal (20
01)
Con
struction of
2 A
lluvi
al r
iver
ter
race
sch
ange
s in sed
imen
t delivery throug
h tim
e clim
atic or tecton
ic con
trols on
land
surfaces
sedimen
t delivery
depo
sitio
nal
Molna
r et
al (199
4) A
nderson et
al (19
96) Rep
ka eta
l (199
7) P
hillips eta
l (199
8) Han
cock eta
l (199
9) S
challer et
al 2
002) S
child
gen et
al (20
02)
3 A
lluvi
al f
ans
debr
is f
low
sag
e co
nstraints on
seism
ic activity
throug
h offsettin
g by
faults
Ritz
eta
l (199
5) B
ierm
an eta
l (199
5) L
iu eta
l (199
6) S
iame et
al (19
97 2
002) B
rown et
al
(199
8a) va
n de
r Woe
rd eta
l (199
8 200
2) C
erlin
g (1
990) K
linge
r et
al (20
00) Zeh
fuss eta
l (200
1)
Fenton
eta
l (200
1) H
etzel et
al (20
02a b) Jackson et
al (200
2)
4 L
acus
trin
e sh
orel
ine
depo
sits
chron
olog
y of te
cton
ic deformation palae
ohyd
rology
and
clim
atic cha
nge
Trull e
tal (199
5)
5 I
ce-m
argi
nal m
orai
nes
glac
ial h
istory c
limatic cha
nge
Brown et
al (19
91) Brook
eta
l (199
3 199
5a b
) Brook
and
Kurz (199
3) G
osse eta
l (199
5a b)
Phillips et
al (19
90 1
996 199
7) Z
reda
and
Phillips (1
995) Ivy
-Och
s et
al (19
96 1
997) F
abel eta
l (199
7) Jac
kson
eta
l (199
7 199
9) C
hadw
ick et
al (19
97) Steig et
al (19
98) Davis eta
l (199
9) F
abel
and Harbo
r (199
9) G
ualtieri e
tal (200
0) S
hana
han an
d Zreda
(200
0) T
schu
di eta
l (200
0) M
arsella
etal (20
00) Ph
illips et
al (200
0) Barrows et
al (20
01 20
02) Brine
r et
al (20
01 2
002) L
icciardi eta
l (200
1) O
wen
eta
l (200
1 200
2a b
c) Kap
lan et
al (200
1) M
iller eta
l (200
2) S
chaumlfer eta
l (200
2a
b) B
ourlegraves eta
l (200
2) B
owen
eta
l (200
2) P
hillips and
Bow
en (2
002) Jam
es eta
l (200
2)
6 M
arin
e sh
orel
ine
depo
sits
relative sea-level c
hang
ePe
rg eta
l (200
1)
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
10 Geomorphological applications of cosmogenic isotope analysis
Table 2
Con
tinu
ed
Nature of
Category of
App
lications w
ith exa
mples
proc
ess
proc
ess
Even
tEx
posure th
roug
h7
Dev
elop
men
t of
fau
lt s
carp
spa
laeo
sesimicity
earthqu
ake recu
rren
ce in
tervals reg
iona
l tecton
ic
(age
)tecton
ic
stud
ies
(con
t)displace
men
tZreda
and
Noller (199
8) H
andw
erge
r et
al (19
99) Mitc
hell et
al (200
1)
Episod
ic8
Met
eori
te im
pact
sde
nuda
tion of th
eNishiizum
i eta
l (199
1a) Ph
illips et
al (19
91)
land
surface
9 R
apid
mas
s m
ovem
ent(eg land
slides roc
k falls d
ebris avalan
ches top
pling bo
ulde
rs)
mag
nitude
ndashfrequ
ency
relationships of rap
id m
ass mov
emen
t processes c
orrelatio
n with
clim
atic
chan
ge or seismic eve
nts
Kubik et
al (19
98) Ivy-Och
s et
al (19
98) Ballantyn
e et
al (19
98) Bell e
tal (199
8) C
erlin
g et
al
(199
9) H
erman
ns eta
l (200
0 200
1) B
arna
rd eta
l (200
1)10
Cat
astr
ophi
c flo
odin
glake ove
rflows glacial la
ke outbu
rsts lan
dslid
e da
m fa
ilures
Cerlin
g (199
0) C
erlin
g an
d Craig (1
994b
) Cerlin
g et
al (19
94)
11F
orm
atio
nof
stra
thte
rrac
es p
alae
ohyd
rologyc
hron
olog
yan
drate
ofincision
ofassociated
chan
nel Burba
nk eta
l (199
6) L
elan
d et
al (19
98) Barna
rd eta
l (200
1) P
ratt et
al (20
02)
12 F
orm
atio
n of
wav
e-cu
t pl
atfo
rmsch
rono
logy
of relative sea-level c
hang
eSton
e et
al (19
96)
Expo
sure of
13 E
xpos
ure
of b
edro
ck s
urfa
ces
or
glac
ial o
r flu
viog
laci
al d
epos
itio
nal
form
sch
rono
logy
of retreat
land
surface
of ic
e margin con
firmation an
d da
ting of limits of g
laciation from
trim
lines c
hron
olog
y of clim
atic
throug
h ch
ange
remov
alNishiizum
i eta
l (198
9 199
1b) Brook
eta
l (199
6) B
runo
eta
l (199
7) Ballantyn
e et
al (19
98) Ston
eof ice
cov
eret
al (19
98b) B
rine
r an
d Sw
anson (199
8) B
ierm
an eta
l (199
9) F
abel eta
l (200
2) Stroev
en eta
l (200
2) G
osse and
Willen
bring (200
2) G
ualtieri a
nd Brigh
am-G
rette
(200
1) K
elly eta
l (200
2) S
tone
(200
2)
Burial p
roce
sses
14 D
epos
itio
n of
sed
imen
t in
cav
es c
hron
olog
y of cave de
velopm
ent rate of inc
ision of assoc
iated
suba
erial fluvial systems
Grang
er eta
l (199
7 200
1a)
15 B
uria
l of
surf
aces
h
oriz
ons
in d
epos
itio
nal s
eque
nces
cha
nges in
sed
imen
t delivery throug
h tim
eclim
atic or tecton
ic con
trols
Grang
er and
Smith
(200
0) G
rang
er and
Muz
ikar (2
001)
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 11
16 B
uria
l of
glac
ial i
ce g
lacial and
clim
atic history
Schauml
fer et
al (20
00) March
ant e
tal (200
2)
Increm
entalProg
ressive
17 D
enud
atio
n of
bed
rock
reg
olit
h an
d de
posi
tion
al s
urfa
cesby
mecha
nica
l and
or ch
emical
chan
gede
nuda
tion of the
denu
datio
nal p
roce
sses at spe
cific
points on
the land
surface
(site
-spe
cific
rates) in som
e ca
ses
(rate)
land
surface
extrap
olation of site
-spe
cific
rates to
larger areas possible rates of d
enud
ation of differen
t lan
dsca
peelem
ents (e
g rive
r ch
anne
ls v
alley-side
slope
s interflu
ves) a
ssessm
ent o
f fac
tors con
trollin
gde
nuda
tion rates on
spe
cific
land
form
s (eg slop
e clim
ate litholog
y)
Nishiizum
i eta
l (198
6 199
1b) Ku
rz (1
986b
) Albrech
t eta
l (199
3) B
rown et
al (19
95a) B
ierm
anan
d Tu
rner (1
995) S
eidl eta
l (199
7) Sm
all e
tal (199
7 199
9) H
eimsath eta
l (199
7 199
9 200
020
01a b) Weissel and
Seidl (1
998) C
ockb
urn et
al (19
99 2
000) F
leming et
al (19
99) Coc
kburn an
dSu
mmerfie
ld (2
000) S
ummerfie
ld eta
l (199
9a b) B
elton et
al (20
00) Grang
er eta
l (200
1b) van de
rWateren
and
Dun
ai (2
001) B
ierm
an and
Caffee (200
1 200
2)18
Reg
iona
l den
udat
ionrepresen
ting ag
greg
ate effects of den
udationa
l proc
esses ac
ross drainage area
s(areally ave
rage
d de
nuda
tion rates de
rived from
bulk sedimen
t sam
ples) assessmen
t of fa
ctors
controlling
den
udation rates for draina
ge areas as a who
le
Brown et
al (19
95a 199
8b) Grang
er eta
l (199
6 200
1b) Sm
all e
tal (199
9) C
lapp
eta
l (200
020
01 2
002) B
ierm
an and
Caffee (200
1) R
iebe
eta
l (200
0 200
1a b
c) Kirch
ner et
al (20
01)
Scha
ller et
al (20
01) Nicho
ls eta
l (200
2)
Ablation of ic
e19
Rat
es o
f ab
lati
on o
n gl
acie
rs lon
g-term
glacier m
ass ba
lanc
e stud
ies
surfac
esLa
l eta
l (198
7 199
0) L
al and
Jull (199
0 199
2) Jull e
tal (199
4a)
Vertic
al20
Ver
tica
l tra
nslo
cati
on o
f m
ater
ial i
n so
ils m
odes and
rates of soil d
evelop
men
tmov
emen
tsHeimsath eta
l (199
7 199
9 200
0 200
1a b
) Ph
illips et
al (19
98) Ph
illips (200
0)
with
in reg
olith
or
21 V
erti
cal t
rans
loca
tion
of
mat
eria
l in
late
rite
sdu
ricr
usts
mod
es and
rates of formation
othe
r de
posits
Brown et
al (19
94) Liu et
al (19
94) Brauc
her et
al (19
98a b 2
000) S
chroed
er eta
l (200
1)
22 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
slop
e m
ater
ials
nature an
d rates of slope
processes
Small e
tal (199
9) H
eimsath eta
l (200
2)
23 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
aeol
ian
depo
sits
dyn
amics of aeo
lian de
posits
Klein eta
l (198
6) Sh
epard et
al (19
95)
24 V
erti
cal t
rans
loca
tion
of
mat
eria
l wit
hin
dese
rt p
avem
ent
syst
emsform
ation of desert p
avem
ents
Wells eta
l (199
5) S
hepa
rd eta
l (199
5)
Palaeo
-25
Cha
nge
in e
leva
tion
thr
ough
tim
einferred
throug
h ch
ange
in produ
ction rate e
stim
ating pa
staltim
etry
elev
ations and
rate of uplift of the
land
surface
to con
strain te
cton
ic m
odels
Brown et
al (19
91) Brook
eta
l (199
3 199
5a) Ivy-Och
s et
al (19
95) Bruno
eta
l (199
7) S
chaumlfer et
al (199
9) V
an der W
ateren
eta
l (199
9) G
osse and
Stone
(200
1) K
ober eta
l (200
2)
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
12 Geomorphological applications of cosmogenic isotope analysis
of denudation rate since eruption to less than ~3 m Mandash1 and confirming that the flowwas not covered by scoriae or ash during subsequent eruptions Other specific applica-tions of cosmogenic isotope analysis to volcanic landforms have included usingcosmogenic 3He concentrations to investigate zonation and magma evolution of thePotrillo volcanic field New Mexico USA (Anthony and Poths 1992 Eppes andHarrison 1999) constraining surface flow stratigraphy and rates of eruption for SierraNegra the largest of the western Galapagos shield volcanoes (Reynolds et al 1995)dating the displacement of volcanic features to constrain the age of caldera collapse onReacuteunion (Staudacher and Allegravegre 1993) and quantifying rates of Quaternary faultmovement in the Grand Canyon region USA (Fenton et al 2001 see Section IV 2)
b Depositional landforms Applications of cosmogenic isotope analysis to deposi-tional landforms range from glacial moraines and erratics to fluvial terraces alluvialfans and debris flows and lacustrine and marine shorelines Compared with othermethods for dating depositional landforms such as conventional 14C dating and lumi-nescence techniques the advent of in situ cosmogenic isotope methods has greatlyexpanded both the temporal range that can be addressed and the variety of sites thatcan be studied
The dating of moraines and other glacial deposits through surface exposure ages hasbeen a major application of cosmogenic isotope analysis with most studies beingfocused on the chronology of the associated glacier fluctuations and their broaderclimatic and environmental implications rather than with the dating of glaciallandforms per se Locations for such studies are worldwide ranging from the BritishIsles (Bowen et al 2002) to eastern Russia (Gualtieri et al 2000) the western USA(Zreda and Phillips 1995 Gosse et al 1995a b Phillips et al 1996 1997 1990Chadwick et al 1997 Licciardi et al 2001 James et al 2002) western Canada (Jacksonet al1997 1999) eastern Canada (Steig et al 1998 Davis et al 1999 Marsella et al 2000Kaplan et al 2001 Miller et al 2002) East Africa (Shanahan and Zreda 2000) southeastAustralia and Tasmania (Barrows et al 2001 2002) the Himalayas and Tibetan Plateau(Phillips et al 2000 Owen et al 2001 2002a b c Taylor and Mitchell 2002 Schaumlfer etal 2002a) and Antarctica (Brown et al 1991 Brook and Kurz 1993 Brook et al 19931995a b Fabel et al1997) A focal issue for a number of these and other studies ofglacial deposits has been the chronology of glacial fluctuations marking the Late GlacialMaximum and the global synchrony or otherwise of the Younger Dryas (Ivy-Ochs etal 1996 1999 Tschudi et al 2000 Briner et al 2001 2002 Phillips and Bowen 2002Bourlegraves et al 2002 Schaumlfer et al 2002b) However in attempting to date the rapidclimatic fluctuations represented by the last glacial to post-glacial transition and inparticular to identify any leads and lags in the climatic system between the northernand southern hemispheres the current resolution of cosmogenic isotope analysis isbeing pushed to its limits especially in view of uncertainties in cosmogenic nuclideproduction rates resulting from regional differences over time in the geomagnetic fieldand in mean atmospheric pressure (Stone 2000 Gosse and Stone 2001)
The simplest model for dating glacial moraines and similar glacial depositional formsassumes that blocks of bedrock with no prior exposure to cosmic radiation are eitherentrained at the glacier base or fall on to the glacier surface and are rapidly incorpo-rated as englacial debris Subsequently these boulders are exposed at the surface whenthe ice cover is removed Various factors however can produce more complex
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
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Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
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Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
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Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
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32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
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Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
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Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
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Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 13
scenarios and these can result in a moraine of a particular age having constituentboulders with a range of cosmogenic surface exposure ages and indeed moraines withidentical cosmogenic exposure ages not being correlative (Hallet and Putkonen 1994)One of these factors is inheritance where individual boulders already contain asignificant inventory of cosmogenic nuclides through exposure to cosmic radiationprior to incorporation as englacial or subglacial debris Others are the differentialweathering and erosion of boulders of contrasting lithologies and the progressiveexposure of boulders in a moraine through the removal of overlying finer materialInheritance which appears to characterize 10ndash20 of moraine boulders (Gosse andPhillips 2001 Briner et al 2001) produces exposure ages greater than the age of themoraine whereas erosion gives rise to younger ages The variation in exposure age asa result of erosion which is obviously more significant on older moraines has beenmodelled by Zreda et al (1994) but a common strategy for dating a moraine is simplyto discount individual boulders with exposure ages significantly younger or older(typically by several standard deviations) than the overall mean age (eg Zreda et al1999 Briner et al 2002) In spite of these issues of data interpretation the potential ofcosmogenic isotope analysis to identify complex moraine sequences and to challengeprevious chronologies of glacial landform development based on correlation throughstratigraphic position is clear (Fabel and Harbor 1999 Zreda and Phillips 1995)
The question of inheritance is also prominent in applications of cosmogenic isotopeanalysis to other depositional landforms such as fluvial terraces (Molnar et al 1994)alluvial surfaces (Liu et al 1996) and shoreline deposits (Trull et al 1995) In datingfluvial terraces in Wyoming and Utah Anderson et al (1996) addressed the problem byanalysing two amalgamated samples of 30 clasts each one from the surface and onefrom the subsurface at a depth sufficient for the sample to have been shielded frompost-depositional cosmic-ray exposure This enabled them to constrain cosmogenicnuclide accumulation prior to deposition Developments of this approach involvingmultiple-sample depth profiles have been used to date suites of fluvial (Repka et al1997 Hancock et al 1999) and marine (Perg et al 2001) terraces while Phillips et al(1998) have modelled different vertical profile patterns of cosmogenic 21Ne concentra-tions in stream terraces and alluvial fan deposits in New Mexico to assess the effects onexposure age of inheritance changes in bulk density erosion and burial Where the ageof a river terrace is independently known then the measured cosmogenic nuclide con-centrations can be corrected for post-depositional production and the remainingcosmogenic nuclide inventory used to estimate the catchment-wide rate of denudationat the time of terrace formation (Schaller et al 2002) More generally cosmogenicsurface exposure dating of fluvial terraces has significant potential for recordingepisodic incision and aggradation in fluvial systems over timescales of 104ndash105 yr(Schildgen et al 2002) and thereby providing much needed chronological constraintson models of episodic erosion and complex response
2 Tectonic displacement
A major application of cosmogenic isotope analysis has been the dating of faultmovements to infer slip rates and earthquake recurrence intervals The advantage ofcosmogenic exposure dating here is that timescales typically up to 50 ka can be
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
14 Geomorphological applications of cosmogenic isotope analysis
addressed and seismic activity is therefore being monitored over geologically usefultime spans In the majority of studies surface exposure dating of displaced deposition-al features has been used to provide age constraints on fault movement Offsets onalluvial fans have been used in central Asia (Ritz et al 1995 Brown et al 1998a Hetzelet al 2002a b ) the southwest USA (Bierman et al 1995 Fenton et al 2001 Zehfuss etal 2001) Argentina (Siame et al 1997) and Jordan (Klinger et al 2000) on piedmontalluvial surfaces in Argentina (Siame et al 2002) and on fluvial terraces at severallocations along the Kunlun fault in Tibet (Van der Woerd et al 1998 2002) In OtagoNew Zealand Jackson et al (2002) have inferred the rate of propagation of an anticlineabove a blind reverse fault from the trend in cosmogenic 10Be exposure ages of largesilcrete boulders on the crest of the resulting uplifting ridge
Fault displacement histories can also be inferred from cosmogenic nuclideinventories in bedrock fault scarps (Zreda and Noller 1998) Measuring in situ-produced 14C in limestone Handwerger et al (1999) have estimated an age of ~4600 yrfor the most recent movement of a fault in northern Utah while Mitchell et al (2001)have compared measured accumulations of cosmogenic 36Cl concentrations on alimestone scarp face in northern Israel with modelled accumulations through timebased on different fault displacement scenarios In this latter study the best matchesbetween modelled and measured 36Cl concentrations indicated episodic behaviour ofthe fault and variations in mean displacement rate over the past 14 ka
3 Episodic denudation
a Meteorite impacts Perhaps the clearest example of an lsquoinstantaneousrsquo denudation-al event that exposes bedrock previously shielded from cosmic radiation is the creationof a crater by an impacting bolide One of the most significant early applications ofcosmogenic isotope analysis was the dating of the Meteor Crater impact site in ArizonaUSA Previous age estimates had ranged from 25 plusmn 5 ka based on stage of soildevelopment to 49 plusmn 3 ka from thermoluminescence data Two independent studiesemploying 36Cl (Phillips et al 1991) and 10Be and 26Al (Nishiizumi et al 1991a)confirmed the thermoluminescence dating with Phillips et al (1991) finding a mean ageof 497 plusmn 085 ka for four ejected boulders and Nishiizumi et al (1991a) establishing anoverall lower bound on the crater age of 492 plusmn 17 ka Cosmogenic isotope analysis isclearly applicable to dating recently formed terrestrial impact structures and therebyimproving estimates of impact recurrence intervals although erosional weathering andburial effects make sampling and data interpretation more complex for older craters
b Rapid mass movement An important issue in geomorphology is gaining anaccurate assessment of the significance in landscape development of highmagnitudendashlow frequency events Rapid mass movement represents a suite ofprocesses which are difficult to monitor directly because of their low frequencyalthough they may represent an important mode of hillslope transport in a number ofgeomorphic settings Dating of these events through cosmogenic isotope analysis is notonly yielding valuable insights into their role vis-agrave-vis other geomorphic processes butalso providing key quantitative data on slope failure processes and recurrence intervalsand for natural hazard assessment
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
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Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
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Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
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32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
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J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
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Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
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Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
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Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
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Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
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Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
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Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
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Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
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Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 15
Examining post-glacial landsliding on the Isle of Skye Ballantyne et al (1998)analysed cosmogenic 36Cl in two blocks exposed during slope failure but originatingwell below the original surface (in order to eliminate any inherited cosmogenic 36Cl)The measured surface exposure age of 65 plusmn 05 ka post-dates deglaciation by severalthousand years and slope failure was therefore thought to be caused by joint extensionand rock bridge shearing andor seismic activity rather than related to periglacialconditions In attempting to relate rock failure events to seismic activity Hermanns etal (2000 2001) have used cosmogenic 21Ne to date eight superimposed rock avalanchedeposits on the Puna Plateau in the central Andes ranging in age from 152 to 31 ka toinvestigate the influence of active faulting on slope oversteepening and subsequentgravitational collapse In another study Bell et al (1998) estimated the period elapsedsince the last major seismic event at sites in California and Nevada by determiningminimum- and maximum-limiting ages (using respectively rock-varnish microlamina-tions and cosmogenic 36Cl) of precariously balanced boulders that could be toppled bystrong ground motion
An important aspect of rapid mass movement events is their significance in environ-mental management Through the relatively long timescales that it is able to addresscosmogenic isotope analysis can provide valuable benchmark data for comparison withhistorical or modern rates For instance in the Garwhal Himalaya northern IndiaBarnard et al (2001) have compared estimates of the enhancement of modern rates oflandsliding and erosion caused by human activity (mostly through the removal of slopetoes at road cuts) with longer-term rates of landsliding and river incision derived fromcosmogenic 10Be and 26Al dating of strath terraces and two large (gt10 million m3)midndashlate Holocene slides They concluded that in their study area anthropogenicinfluences are accelerating rates of denudation Debris flows can play a significant rolein modifying river channels through creating rapids or natural dams and theirfrequency is important in the management of regulated rivers Using a range ofhistorical data and a variety of chronological techniques in association with cosmogenic3He exposure dating of olivine phenocrysts in basalt clasts Cerling et al (1999) havebeen able to estimate recurrence intervals for debris flows entering the Grand Canyonreach of the Colorado River at tributary junctions
In addition to the application of cosmogenic surface exposure dating to rapid massmovement events of previously unknown age independently dated events arepotentially valuable sites for calibrating cosmogenic nuclide production rates sincemajor landslides instantaneously expose rock previously buried below the depth ofcosmic ray penetration For example the age of the Koumlfels landslide in Austria (9800 plusmn100 yr dendro-calibrated relative to 1995) has been tightly constrained by 14C dating ofburied wood and this has been used to determine the production rates of cosmogenic10Be and 26Al (Ivy-Ochs et al 1998 Kubik et al 1998)
c Catastrophic flooding As with major landslides sites experiencing rapid erosionof bedrock or large boulders through deep scouring by catastrophic floods can bevaluable for cosmogenic nuclide production rate studies when there is independentdating of flood events For instance erosion by the Bonneville flood in the Snake RiverPlain at the end of the last glacial (~176 ka BP) has been used by Cerling (1990) andCerling and Craig (1994b) to provide calibration sites for cosmogenic 3He productionCosmogenic surface exposure dating also has the potential to provide ages for
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
16 Geomorphological applications of cosmogenic isotope analysis
previously undated catastrophic flooding events as illustrated by the study of Cerlinget al (1994) who used cosmogenic 3He and 21Ne in basalt boulders and scoured bedrockto date the Big Lost River flood through Box Canyon in south-central Idaho A range ofages amongst the samples was ascribed to inheritance of pre-flood cosmogenic nuclideproduction but together the data indicated a maximum age of ~205 plusmn 19 ka for the BigLost River flood This is essentially identical to the 3He age of 205 plusmn 08 ka for theOwens River flood in California (Cerling 1990 Cerling and Craig 1994b) Both agescorrelate with the beginning of the Missoula floods in the northwest USA and togetherthey may indicate the start of glacial melting in the western USA (Cerling et al 1994)
d Strath terraces While catastrophic floods can scour bedrock to depths of manymetres in a single event lateral erosion of bedrock valley walls and progressive verticalincision of bedrock channels by lsquonormalrsquo flood events can create flights of strath terraceswhose height above the present channel and surface exposure age (time elapsed sinceabandonment) can together yield long-term mean rates of channel incision Suchincision rates are a key variable characterizing regional-scale rates of denudation andlandscape change especially in active orogenic settings For instance in the middlegorge of the Indus River near Nanga Parbat in the northwest Himalayas cosmogenic10Be and 26Al surface exposure ages of well-preserved strath terraces up to 410 m abovethe present channel indicate incision rates of 1ndash12 m kandash1 with an acceleration of rates15 ka ago (Burbank et al 1996 Leland et al 1998) To the southeast in the GarwhalHimalaya Barnard et al (2001) have inferred a fluvial incision rate of 4 m kandash1 from twocosmogenically dated terraces above the Alaknanda River in their study focused onrates of landsliding Strath terraces often exhibit patchy alluvial cover implying acomplex history involving temporary burial after their initial formation Careful fieldassessment prior to sampling is therefore necessary in order to assess the suitability ofa simple surface exposure model (Molnar et al 1994 Anderson et al 1996) Where asimple exposure history does not apply surface exposure ages of flights of strathterraces cannot be used directly to estimate channel incision rates but may yield otheruseful information For instance Pratt et al (2002) found similar surface cosmogenic(10Be and 26Al) exposure ages of around 7 ka BP for fluvially eroded surfaces in centralNepal across a height range of 43ndash124 m above the channel of the Marsyandi River andinterpreted this to be the result of filling of the valley by sediment at least 80 m thickduring a period of more active landsliding triggered by enhanced early Holocenemonsoonal precipitation
e Wave-cut platforms Analogous to the cutting of new surfaces into bedrock byfluvial channel incision is the formation of wave-cut platforms through the erosiveeffects of wave action on shoreline bedrock outcrops The exposure histories (formationages) of these landforms are important both in tracking relative sea-level change andwhere the global sea-level change is independently constrained quantifying rates ofactive tectonic or glacio-isostatic surface uplift Although radiocarbon dating andother radiometric techniques have been widely employed notably to raised coral reefscosmogenic isotope analysis is valuable where the bedrock or associated deposits arenot suitable for these other dating methods Stone et al (1996) have presented data forthe lsquoMain Rock Platformrsquo in western Scotland with cosmogenic 36Cl apparent ages orlsquoeffective irradiation timesrsquo based on a simple exposure model They note however that
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 17
this will not represent the true age if marine transgressions or other temporaryshielding effects are not taken into account Nonetheless even with these uncertaintiestheir study demonstrates that apparent ages alone place the formation of the Main RockPlatform firmly in the termination phase of the last glacial
4 Removal of ice cover
Conceptually one of the simplest applications of cosmogenic isotope analysis is datingthe removal of an ice cover from bedrock surfaces moraines or glacial erratics It is notsurprising therefore that much emphasis was placed on this kind of study in the initialapplications of cosmogenic surface exposure dating For instance Nishiizumi et al(1989) used glacially polished rocks exposed by the (radiocarbon-dated) retreat of Tiogastage glaciers in the Sierra Nevada to calibrate 10Be and 26Al production rates (see alsoClark et al 1995) Cosmogenic isotope exposure dating of glacial retreat across bedrocksurfaces has subsequently been applied in Antarctica (Nishiizumi et al 1991b) easternCanada and the Arctic (Bierman et al 1999 Gualtieri and Brigham-Grette 2001) and theSwiss Alps (Kelly et al 2002) Many studies of the chronology of glacial retreat havecombined data on bedrock forms with the exposure of glacial depositional landformsthe assumption being that careful sampling from features such as moraines and erraticscan also provide reliable constraints on the timing of glacial retreat (eg Ivy-Ochs et al1997 Steig et al 1998 Schaumlfer et al 1999 Zreda et al 1999 Marsella et al 2000 Kaplanet al 2001 Karhu et al 2001 Owen et al 2001 2002b Bourlegraves et al 2002 Bowen et al2002 Oberholzer et al 2002 James et al 2002 Stone et al 2002) (see Section IV 1 b)
An exposure age for the removal of ice cover through glacial retreat or wasting willonly be valid if the thickness of shielding ice (several multiples of the attenuation lengthfor ice) has been sufficient to effectively shut down cosmogenic nuclide productionMoreover the depth of scouring by glacial erosion prior to a glacial retreat episode hasto be great enough to remove the vertical zone of bedrock in which cosmogenic nuclidesproduced during any earlier exposure episode would be residing If this were not thecase the cosmogenic nuclide concentration measured would include an inheritedcomponent In some studies such as that for Tumbling Glacier Baffin Island (Davis etal 1999) samples collected just beyond an actively retreating ice front have indeedbeen found to contain minimal cosmogenic nuclide concentrations But instances wherethis is not the case can provide valuable insights into the effectiveness of glacial erosionduring individual episodes of glacial advance For example assuming that anyinherited cosmogenic nuclide component related only to the most recent interglacialBriner and Swanson (1998) calculated an erosion rate of 009ndash035 mm yrndash1 for theCordilleran Ice Sheet at Mt Erie in the Puget Sound region of Washington State USAfrom excessive cosmogenic 36Cl concentrations compared with the well-constrainedradiocarbon deglaciation age In studying the possible preservation of preglacialtopography in areas subject to frozen bed conditions under the Fennoscandian Ice Sheetin Sweden Fabel et al (2002) and Stroeven et al (2002) have found that cosmogenicnuclide concentrations in erratic boulders gave consistent deglaciation ages thusconfirming ice sheet overriding as opposed to ice-free conditions but concentrations of10Be and 26Al in preserved tors within the landscape suggested minimal erosion overseveral glacial cycles Similarly Bierman et al (1999) and Gosse and Willenbring (2002)
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
18 Geomorphological applications of cosmogenic isotope analysis
have found complex exposure histories and evidence of inheritance indicating differ-ential erosion under the Laurentide Ice Sheet
The vertical extent of former glaciers and ice sheets is an important variable requiredfor determining past ice volumes and for palaeoclimatic reconstructions Geomorphicindicators of previous ice levels range from clearly defined trim lines to more equivocalweathering limits which may reflect other zones of process transition such as post-glacial differential weathering or englacial boundaries between wet-based eroding iceand noneroding frozen-bed ice Cosmogenic exposure dating of bedrock surfaces acrossthese transition zones can help to distinguish between different processes of formationas well as providing information on the chronology of changes in ice volume (Brook etal 1996 Stone et al 1998b)
5 Burial events
a Sediment burial In addition to the chronological information that can be derivedfrom cosmogenic nuclide concentrations in deposits formed on the land surfacevaluable information can also be garnered in circumstances where sedimentspreviously exposed to cosmic radiation are rapidly buried beyond the zone ofcosmogenic nuclide production This is because the differential decay of cosmogenicnuclides with different half-lives will indicate the time elapsed since burial and hencethe date of deposition A particularly useful situation in which such rapid sedimentburial occurs is in caves and in the first use of this application Granger et al (1997)measured cosmogenic 10Be and 26Al concentrations to date burial times of alluviumdeposited in abandoned caves above the present level of the New River Virginia USAand to constrain the rate of downcutting of the river during the Quaternary Granger etal (2001a) also constrained the evolution of Mammoth Cave in Kentucky by dating aseries of sediments deposited by the Green River They were able to show that theriverrsquos incision history was in step with major climatic changes and drainage reorgani-zations associated with fluctuations in the margin of the Laurentide Ice Sheet
The cosmogenic nuclide inventories in sediments buried within depositional formssuch as river terraces can also provide valuable chronological information Forexample although determining the cosmogenic nuclide concentration of surfacesamples can yield valid ages for well-preserved river terraces (see Section IV 1 b) thisstrategy cannot be applied to older degraded terraces which may have experiencedseveral metres of erosion In such cases however the differential decay of tworadioactive cosmogenic isotopes (commonly 26Al and 10Be) collected from depth can beused to estimate the age of terrace formation assuming that post-burial cosmogenicnuclide production is known (Granger and Smith 2000) Such production can continueat a depth of several metres because of the deep penetration of fast muons (Granger andSmith 2000 Granger and Muzikar 2001)
b Burial of glacial ice An unusual but key application of cosmogenic isotope datato constrain the chronology of a burial event is provided by the controversy over theage of a subsurface body of glacial ice in Beacon Valley Southern Victoria LandAntarctica The significance of this buried ice is that if it is of Miocene age (minimum81 Ma BP) ndash as has been inferred from stratigraphic relationships to overlying tills
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
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Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
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Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
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Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
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Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
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ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
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Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 19
dated by 40Ar39Ar analyses of presumed in situ volcanic ash ndash it confirms thepersistence of a cold hyper-arid climate in the area throughout the Pliocene and refutesthe notion of an unstable East Antarctic Ice Sheet during this period (Sugden et al1995) The ability of ice in the near subsurface to survive sublimation over the timespans proposed has been questioned (Hindmarsh et al 1998) as has the interpretationthat the volcanic ash deposits are undisturbed and thus provide a chronologicalconstraint on the age of the ice Through an analysis of the concentrations ofcosmogenic 3He and 21Ne in two surface dolerite erratics and one shielded erratic fromwithin the ice Schaumlfer et al (2000) demonstrated that sublimation rates could not haveexceed more than a few metres per million years and that the ice must be at least severalmillion years old Marchant et al (2002) have addressed the question of whether thevolcanic ash is in situ especially in view of the presence of well-developed polygonalpatterned ground developed in the till Two profiles of cosmogenic 3He concentrationsthrough the till deposit show it to have formed through sublimation of the underlyingice and indicate the long-term stability of the till layer in areas unmodified by patternground formation
V Incremental change
1 Site-specific denudation rates
As pointed out in Section III most of the Earthrsquos surface is subject to the incrementalchange associated with bedrock weathering hillslope processes and sediment andsolute transport rather than discrete geomorphic events involving the instantaneousexposure of rock through the removal of several metres of overburden Consequentlyrather than thinking of an lsquoevent exposure agersquo in most cases it is more meaningful tointerpret concentrations of cosmogenic nuclides as reflecting these rates of incrementaldenudation
The key to quantifying denudation rates using surface concentrations of cosmogenicnuclides is changes in production with depth since denudation involves bringing up tothe surface rock that was previously buried In a steadily eroding rock outcrop thecosmogenic nuclide concentration approaches saturation or secular equilibrium as aresult of constant production on the one hand and losses by denudation as well asradioactive decay (in the case of radionuclides) on the other After initial exposuresecular equilibrium will be reached when sufficient time has elapsed for denudation toremove a depth of rock two or three times the attenuation length (see Section III)assuming denudation has been occurring in small increments relative to the attenuationlength Under these circumstances a measured surface concentration can be accuratelymodelled in terms of a constant denudation rate representing an integrated rate for theminimum period of time required to reach secular equilibrium (Nishiizumi et al 1986Kurz 1986b Lal 1991) This model is commonly referred to as the lsquosteady-state erosionmodelrsquo with the term lsquosteady-statersquo often used to refer to both secular equilibrium andthe particular style of denudation required to satisfy the model If the system has notyet reached saturation then the model will overestimate the denudation rate whereasif erosion is occurring episodically (ie in increments that are large relative to theattenuation length) or the exposure history is complex and has included periods ofburial then the model may either overestimate or underestimate the true rate (Lal 1991
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
20 Geomorphological applications of cosmogenic isotope analysis
Small et al 1997) In favourable circumstances the ratio of two radionuclides withdifferent half-lives can be used to test the assumptions of the steady-state erosionmodel The ratios of 10Be and 26Al are commonly used in such cases to test for complexexposure histories involving burial episodes andor episodic or highly temporallyvariable denudation rates with the behaviour associated with particular isotope ratiosbeing depicted on an erosion-island graph (Klein et al 1986 Lal 1991) Measurementuncertainties mean that the test for episodic denudation may be inconclusive progres-sively more so for denudation rates gt1 m Mandash1 (Small et al 1997) Nonetheless eventhough errors resulting from an inappropriate application of the steady-state erosionmodel can be greater than both measurement and production rate errors a moreaccurate denudation rate estimate can be obtained by calculating the mean from manyindividual steady-state erosion rate measurements (Small et al 1997)
Site-specific denudation rates based on the steady-state erosion model have beenestimated for a wide range of locations and geomorphic settings (Table 3) These ratesare naturally biased towards low values because of preferential sampling of barebedrock surfaces that are usually the most slowly eroding and resistant components ofthe local landscape Variations in rates can also be evident depending on microtopog-raphy and other detailed characteristics of the specific sampling site selectedExtrapolation of these rates across the landscape can therefore be problematic anduncertainties can arise from the difficulties in strictly fulfilling the assumptions of thesteady-state erosion model Notwithstanding these caveats the studies listed in Table 3represent a major advance in quantifying rates of denudation integrated over geomor-phologically useful periods of time (103ndash106 years) compared with the previous paucityof data relevant to these timescales That uncertainties over the appropriate erosionmodel in any particular case together with analytical and production rate errors mayproduce total errors in denudation rate estimates in some cases exceeding 50 must beplaced in the context of the lack of data for similar timescales provided by othertechniques Whilst such large errors would be unacceptable in cosmogenic surfaceexposure studies attempting for instance to resolve uncertainties in the timing of lateglacial events they may not be problematic in studies where establishing approximaterates of denudation is sufficient to test often long-standing notions about rates andmodes of landscape change For example cosmogenic-nuclide based estimates ofescarpment retreat rates of 10ndash100 m Mandash1 over the past 104ndash106 yr for the GreatEscarpment in southern Africa contrast with a mean rate of retreat of the order of 1000m Mandash1 implied by Kingrsquos classic model of landscape evolution for the area (Fleming etal 1999 Cockburn et al 2000) Similarly although cosmogenic nuclide concentrationshave demonstrated some exceedingly slow rates of denudation of ~5 m Mandash1 or less forerosion surfaces and inselbergs in Australia southern Africa and Antarctica(Nishiizumi et al 1991b Bierman and Turner 1995 Cockburn et al 1999 Cockburn andSummerfield 2000 Summerfield et al 1999a b Belton et al 2000 Bierman and Caffee2001) these rates would still be too high to preserve intact erosion surfaces over thetime intervals of up to 50 Ma or more that have been proposed
2 Catchment-averaged denudation rates
An obvious potential limitation of site-specific sampling in providing data relevant todenudation rates at a broader scale is the lsquononrandomrsquo nature of sample selection
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 21
Where sampling is from bedrock outcrops in terrain that is predominantly blanketed byregolith denudation rates are likely to be less than the regional average since exposedbedrock is likely to be present because it is eroding less rapidly than its surroundingsIn principle however the process of denudation from the weathering of bedrock to thetransport of material on slopes and the transmission of sediment in river channelsprovides a natural sampling mechanism whereby each of many thousands ofindividual mineral grains in a river sediment sample will carry its own history ofexposure to cosmic radiation By averaging together these individual exposure historiesthrough the analysis of a single sample of sediment from a river channel it is possibleto estimate the mean rate of denudation for the catchment area upstream of thesampling site This principle was first suggested by Lal and Arnold (1985) and wastested by Brown et al (1995a) in the Icacos basin in Puerto Rico where a denudation rateof ~43 m Mandash1 was estimated This study together with that of Granger et al (1996)identified a range of factors that have to be addressed in making such denudation rateestimates these include variations in production rates throughout the basin (especiallyas a function of elevation) variations in bedrock mineralogy the storage and remobi-lization of sediment differential weathering of different calibre grains regolith mixingthrough bioturbation physical weathering and slope processes and the mixing ofsediment from areas of different erosion rates In evaluating the method Granger et al(1996) compared denudation rates estimated from cosmogenic nuclide concentrationsin present-day river sediment with rates derived from sediment volumes in well-datedalluvial fans in two small catchments in northeast California The close correspondencebetween the two sets of estimates confirmed that in small catchments with littlesediment storage cosmogenic nuclide concentrations in river sediment can provide agood estimate of basin-wide long-term denudation rates In a general assessment of theviability of this basin-averaged approach to cosmogenic isotope analysis Bierman andSteig (1996) concluded that it provides an effective means of estimating denudationrates in basins in isotopic steady state and where the sampled sediments are wellmixed However care has to be taken where quartz grains are being analysed (as isfrequently the case for cosmogenic 10Be and 26Al) since the relative resistance of quartzto dissolution means that its residence time in regolith will be longer than the averagefor all mineral grains (Small et al 1999) although the resulting bias is probably modestcompared with the other uncertainties in cosmogenic denudation rate estimates (Riebeet al 2001a)
The ability to use cosmogenic nuclide concentrations to characterize basin-wide aswell as site-specific denudation rates has provided the opportunity to compare areallyaveraged denudation rates with those for specific landform elements and subcatch-ments within basins For instance Granger et al (2001b) showed that in the DiamondMountains batholith in California exposed granite bedrock has been eroding moreslowly than the average rate for catchments in which they are found Similarly Biermanand Caffee (2001) found that denudation rates for bedrock samples in Namib Desertwere lower than catchment-averaged rates from channel sediment samples In theYuma Wash basin in southwest Arizona Clapp et al (2002) used channel sedimentsamples to compare sediment generation rates for subcatchments as well as the basinas a whole They found that in the upland subcatchments cosmogenic nuclide concen-trations reflect rates of sediment generation from bedrock weathering whereassediment in the main channel also includes the long-term effects of sediment storage
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
22 Geomorphological applications of cosmogenic isotope analysis
Table 3
Site-specific den
udation rates determined
from in situ-produced cosmog
enic nuclides in
bed
rock
sam
ples
Sour
ceLo
cati
onLi
thol
ogy
Fiel
d se
ttin
g an
d co
mm
ents
Isot
ope
nR
ate
(mm
kandash1
)
Mea
nR
ange
Nishiizum
i et
al
Alla
n Hills sou
thern
sand
ston
eSamples from bou
lders an
d be
droc
k ou
tcrops
907
03ndash
13
1991
bVictoria La
nd
from
Bea
con Su
pergroup
Antarctica
Soumlr Ron
dane
Mts
Mea
n rate and
ran
ge exc
lude
two samples w
ith10Be
6017
006
ndash045
Droning
Mau
d La
nd
complex
exp
osure history
26Al
Antarctica
Wrigh
t Valley sou
thern
sand
ston
eBed
rock from horizon
tal platform
s7
09
05ndash
13
Victoria La
nd
Antarctica
Summerfie
ld eta
l Dry Valleys region
gran
ite
Rectilinea
r slop
e samples
4056
026
ndash102
1999
asouthe
rn Victoria La
nd
sand
ston
ePlateau surfac
e samples
21Ne
4015
013
ndash016
Antarctica
Brown et
al
Icac
os River Lu
quillo
quartz-diorite
Bed
rock ridge
crest sam
ples
10Be
225
ndash19
95a
Mts P
uerto Rico
Small et
al
Wind River W
yoming
gran
ite gn
eiss
775
3ndash12
1997
USA
Bea
rtoo
th
Mon
tana
USA
gran
iteTo
r an
d large bo
ulde
r samples from sum
mit
10Be
510
56ndash
19Fron
t Ran
ge Colorad
ogran
ite schist
flats (2ndash
10degslop
e) sho
wing no
evide
nce of prior
26Al
474
6ndash9
USA
glaciatio
nSierra N
evad
agran
ite3
30
2ndash5
Califo
rnia USA
Small et
al
Wind River Ran
ge
gran
ite gn
eiss
Samles from
regolith
profiles and
buried
10Be
1813
712
16
1999
Wyo
ming U
SAbe
droc
k26Al
Heimsath eta
l Marin Cou
nty northern
gree
nstone
Isolated
bed
rock outcrop
s on
hillslop
es10Be
324
715
ndash39
1997
19
99Califo
rnia USA
grey
wacke
From
sub
soil be
droc
k samples on hillslope
s26Al
1146
521
ndash105
sand
ston
e che
rtestim
ated
assum
ing steady
-state soil thickn
ess
Heimsath eta
l Coa
st Ran
ge
sand
ston
eFrom
sub
soil be
droc
k on
sam
ples on hillslope
s20
01a
Orego
n U
SAsiltstone
estim
ated
assum
ing steady
-state soil thickn
ess
10Be
3112
25
15ndash3
59(alth
ough
field ev
iden
ce sug
gests tempo
ral
26Al
variation in loc
al soil de
pth)
Grang
er eta
l Diamon
d Mts
hornblen
de
382
6ndash12
2001
bCalifo
rnia USA
gran
odiorite
Bed
rock sam
ples from exp
osures along
10Be
Fort Sag
e Mts
biotitie-gran
itecatchm
ent ridg
es26Al
119
ndashCalifo
rnia USA
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
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Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
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32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
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rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
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Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
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Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
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Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
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Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
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Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
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Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
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Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
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Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
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36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
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Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 23
Weissel and
Seidl
Mac
leay River System
gran
iteGorgehe
ad erosion
10Be
6~10
052
ndash195
1998
eastern New
Sou
thPlatea
u surfac
e ab
ove go
rge
26Al
140
ndashWales A
ustralia
Bierm
an and
Eyre Pen
insula south-
Bed
rock sam
ples from in
selberg summits
2708
03ndash
25
Turner 1
995
central A
ustralia
gran
iteinclud
ing bo
ulde
rs and
slabs on summit surface
10Be
Bierm
an and
Expo
sed bo
ulde
rs and
bed
rock
sam
ples from
26Al
Caffee 200
2inselberg fla
nks
2121
05ndash
50
Heimsath eta
l Upp
er Beg
a Valley
gran
ite
From
sub
soil be
droc
k saprolite
sam
ples on
2000
New
Sou
th W
ales
gran
odiorite
slop
es at ba
se of esca
rpmen
t estim
ated
10Be
1428
69ndash
57Australia
assuming stea
dy-state soil thickn
ess
26Al
From
sides and
top
s of tors
715
89ndash
26Heimsath eta
l Bread
ho River Valley
gran
iteTo
rs on platea
u hillslope
s10Be
1010
04ndash
2820
01b
southe
astern H
ighlan
ds
26Al
New
Sou
th W
ales
Australia
Bierm
an and
Northern Territo
ry
gran
iteBed
rock sam
ples from to
ps of large bo
ulde
rs7
196
07ndash
37
Caffee 200
2Australia
and inselberg summits
10Be
Bed
rock sam
ples from lo
w lying
roc
k platform
s26Al
and fla
nks of inselbe
rgs
626
12ndash
38
Coc
kburn et
al
Cen
tral N
amib D
esert
gran
iteBed
rock sam
ples from bornh
ardts som
e10Be
651
3ndash7
1999
Nam
ibia
eviden
ce of co
mplex
exp
osure
26Al
Coc
kburn et
al
Gam
sberg cen
tral
gran
ite-gne
iss
Samples from ridges extend
ing be
low
672
2ndash15
2000
Nam
ibian esca
rpmen
tescarpmen
t face
10Be
Nam
ibia
sand
ston
eEscarpmen
t face
sam
ples
26Al
472
5ndash12
Gam
sberg (escarpm
ent) summit
4044
035
ndash050
Bierm
an and
Cen
tral N
amib D
esert
gran
ite gn
iess
Bed
rock sam
ples from to
ps and
flan
ks of
10Be
4735
11ndash
75
Caffee 200
1Nam
ibia
quartz veins
inselbergs and
smaller rocky ou
tcrops
26Al
schist
Van
der W
ateren
Cen
tral N
amib D
esert
Expo
sed veins on
gravel an
d sand
-cov
ered
4
046
011
ndash104
and Dun
ai 20
01Nam
ibia
quartz veins
pedimen
t surface
21Ne
River cut bed
rock surfaces 6
m and
0m abo
ve2
09
041
ndash14
presen
t dry ch
anne
l respec
tively
Flem
ing et
al
Drake
nsbe
rgba
salt
Escarpmen
t face
36Cl
255
48ndash6
219
99Esca
rpmen
tFlat-lying
escarpm
ent sum
mit
36
1ndash10
Not
es rates are mea
n values from all isotop
es used U
ncertaintie
s on
den
udation rates from
ana
lytic
al and
produ
ction rate errors are typically
5ndash2
0
Most de
nuda
tion rate estim
ates assum
e a lsquostead
y-statersquo erosion
mod
el
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
Albrecht A Herzog GF Klein J Dezfouly-Arjomandy B and Goff F 1993 Quaternaryerosion and cosmic-ray erosion history derivedfrom 10Be and 26Al produced in situ anexample from the Pajarito plateau Vallescaldera region Geology 21 551ndash54
Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
24 Geomorphological applications of cosmogenic isotope analysis
and reworking Further west in the Mojave Desert Nichols et al (2002) have measuredcosmogenic 10Be and 26Al in sediment samples to document rates and processes ofpiedmont modification
As well as exploring the spatial variability of denudation rates catchment-averagedrates derived from cosmogenic nuclide concentrations (which reflect denudation overperiods of 103ndash106 years) can usefully be compared with rates derived from modernmeasurements of river sediment yield For instance Brown et al (1998b) usedcosmogenic 10Be in fluvial sediments to assess differences between modern and pre-development rates of denudation in Puerto Rico and found evidence for a significantanthropogenic enhancement of modern sediment discharges In the Negev DesertIsrael Clapp et al (2000) compared the 33-yr sediment budget of a small intensivelystudied basin with cosmogenic 10Be and 26Al estimates of the longer-term sediment fluxand found that the modern rates of sediment transport exceed the longer-term averageby 53ndash86 thus indicating current evacuation of sediment accumulated duringprevious periods of enhanced sediment generation By contrast in the more humidsetting of western Europe Schaller et al (2001) found catchment-averaged denudationrates from cosmogenic 10Be in quartz for catchments in the Allier Meuse Neckar andRegen basins to be 15ndash4 times greater than those derived from modern river loadsThey suggest that this may be due to under-representation in the modern record of highmagnitudendashlow frequency events to inheritance of an elevated Pleistocene signal or tononuniform erosion and preferential sourcing of modern sediment from the deeper(and therefore less cosmogenically exposed) zones of the subsurface A similar rela-tionship between modern and longer-term rates was found by Kirchner et al (2001) intheir assessment of erosion rates over a range of timescales in mountainous graniticcatchments in Idaho USA Here they estimated that mean rates over the past ~10 kaderived from cosmogenic 10Be concentrations in river sediment are on average 17 timesgreater than modern stream fluxes a difference that they interpret as arising from theunderestimation of rare but catastrophic erosional events in short-term stream-loadmonitoring Clearly even these few studies both caution against simple generalizationsabout anthropogenic enhancements of modern sediment discharges and question thereliability of short-term records of river sediment load as indicators of longer-termprocess rates
The growing application of catchment-averaged denudation rates from cosmogenicnuclide concentrations has gone beyond the simple documentation of rates andcomparison of different timescales to the testing of assumptions about the efficacy offactors controlling denudation and landscape development For example measure-ments of cosmogenic 10Be and 26Al in stream sediments in the Sierra Nevada havedemonstrated a strong augmentation of denudation rates in the proximity of faultscarps (Riebe et al 2000) but a lack of correlation with climate (Riebe et al 2001b)Moreover by combining estimates of long-term rates of mechanical denudation fromcosmogenic nuclide concentrations in sediment with estimates of solute loss from theenrichment of insoluble elements in regolith Riebe et al (2001c) have shown a strongcorrelation between rates of mechanical and chemical denudation but a lack ofcorrelation between chemical denudation rates and climate
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 25
3 Accumulation and ablation of ice surfaces
A specific application of cosmogenic isotope analysis of relevance to glacial geomor-phology involves the use of 10Be and 14C produced in situ in ice by neutron spallationof oxygen nuclei as recorders of glacier accumulation and ablation rates (Lal et al 1987Lal and Jull 1990 Jull et al 1994a) This is analogous to the use of cosmogenic isotopesto record sediment deposition and denudation except that it is the accumulation or lossof ice that is being recorded by cosmogenic nuclide concentrations However differen-tiating the in situ component from atmospheric cosmogenic nuclides trapped in airduring the firnndashice transition and those deposited by wet precipitation is complex Thisis particularly so for 10Be since atmospheric sources exceed the in situ component by anorder of magnitude and this kind of application is therefore limited to special cases (Laland Jull 1992) For instance using 14C Lal et al (1990) estimated ice ablation rates of 58plusmn 7 and 76 plusmn 8 mm yrndash1 for two locations in the Allan Hills main ice field Antarcticathese rates being in agreement with those determined using stakes Similarly the 14C-based estimates by Lal et al (1987) of accumulation rates for the Greenland Ice Sheetwere also found to be in line with recent model estimates
4 Regolith and soil development
The depth-dependence of cosmogenic nuclide production rates provides a valuablemeans of quantitatively monitoring those processes in soil and regolith in which thereis a vertical component to the movement of material relative to the surface Using thisapproach data from cosmogenic isotope analysis have started to provide the means toevaluate models of soil and regolith development that were previously untestable withreference to the usually lengthy timescales over which the relevant processes operateAn elegant example is provided by the testing by Wells et al (1995) of a model of stone(desert) pavement formation In contrast to the idea of stone pavements resulting froma progressive concentration of gravel at the surface as a result of the swelling andshrinkage of surrounding fines or through the removal of fines through deflation orsheet wash the similarity of surface exposure ages derived from cosmogenic 3He con-centrations in their pavement gravel and adjacent bedrock samples demonstratedcontinuous exposure of both components As also shown in a similar study by Shepardet al (1995) these data are inconsistent with the gradual emergence of individual gravelclasts over an extended period of time (the lsquolagrsquo hypothesis) but accord with a modelof stone pavement formation involving vertical inflation through the infiltration of finesfrom above
The very extended time periods over which duricrusts lateritic weathering profilesand associated weathering materials typically develop mean that the processes thatform them cannot be adequately encompassed by short-term measurements ormonitoring Cosmogenic nuclides however provide a powerful means of investigatingthe long-term development of such weathering forms through their ability to recordprogressive burial or exposure of components of weathering profiles For instanceBrown et al (1994) used 10Be and 26Al measurements in quartz veins and pebbles inWest African lateritic crusts both to determine erosion rates for the weathering profilesurfaces and to distinguish between profiles that are being eroded from those that areexperiencing burial Other work on Brazilian and African lateritic profiles has used
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
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Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
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Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
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3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
26 Geomorphological applications of cosmogenic isotope analysis
cosmogenic 10Be and 26Al to differentiate between autochthonous and allochthonouscomponents of lateritic systems ndash and hence the role of in situ weathering and colluvialtransport in their development and to constrain models of stone-line formation(Braucher et al 1998a b 2000) Cosmogenic isotope analysis has also been applied tocalcretes using 36Cl with the study by Liu et al (1994) indicating through an increasein age with depth that at their site in southern Arizona calcretes develop by upwardaccumulation and that water movement is very limited once induration has occurredThe potential of cosmogenic isotope analysis to reveal complex components ofweathering profile development is illustrated by the study of Schroeder et al (2001) inthe piedmont zone of Georgia USA Here a significantly younger age (maximum ~8000yr) for 14C bound in gibbsite compared with near surface residence times for quartzbased on 10Be and 26Al inventories of at least 90 ka points to significant recrystalliza-tion of secondary minerals during weathering front propagation into bedrock
5 Soil production erosion and landscape development
The rate at which soil (regolith) is produced is a key geomorphological parameterbecause it is the entrainment and transport of unconsolidated material rather than thedirect erosion of bedrock that dominates in most environments Soil depth is a functionof the rate of soil production and the rate of removal by physical erosion and solutionalloss But it has long been recognized that the rate of soil production is itself alsoinfluenced by soil depth (Gilbert 1877) although the precise nature of this relationshiphas been disputed The relationships between slope soil depth rate of soil productionand rate of hillslope erosion are fundamental to understanding the surface processescontrolling landscape evolution and the ability of cosmogenic isotope analysis toprovide quantitative insights into these processes and their relationships is likely toprovide one of its most significant contributions to geomorphology Already theseapplications are being exploited For instance in a study of regolith production onhillslopes in an alpine environment in Wyoming USA using 10Be and 26Al concentra-tions from depth profiles Small et al (1999) have established that the rate of regolithproduction has been nearly twice as rapid under ~09 m of regolith than that previouslydetermined from erosion rates on bare rock surfaces from similar (although notidentical) alpine environments in the western USA (Small et al 1997)
Making the assumption that bedrock conversion to soil attains a steady state under aconstant soil thickness Heimsath et al (1997 1999) used cosmogenic 10Be and 26Al con-centrations in bedrock at the base of the soil column to evaluate the relationshipbetween soil production rate and soil depth For their field area in northern Californiathey found an exponential decline in production rate with increasing soil depth from77 mm kandash1 with no soil cover to 77 mm kandash1 under a soil depth of 1 m Although fromtheir data they could not rule out a maximum in soil production rate under a thin soilcover (a long-standing notion in geomorphology (Carson and Kirkby 1972)) they wereable to confirm that peak soil production does occur very close to zero soil depthResults from a similar study in southeastern Australia confirmed the exponentialdecline in rates of soil production with increasing soil depth (Heimsath et al 2000)
Extending this approach to an intensively studied field site in the Oregon CoastRange Heimsath et al (2001a) concluded from a 10Be- and 26Al-derived analysis of soil
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 27
production rates that although there may be an approximately constant rate oflandscape erosion over parts of the Oregon Coast Range smaller-scale processes suchas drainage competition and stochastic erosional events especially by biogenicprocesses lead to significant temporal and spatial variations in soil depth Furtherapplications in southeastern Australia illustrate how cosmogenic isotope data can beused to quantify long-term relationships between rates of soil production bedrockincision and regional erosion and regolith stripping (Heimsath et al 2000 2001b)
Another strategy for estimating soil accumulation and erosion rates is provided bydepth profiles of cosmogenic nuclide concentrations in soils (Phillips et al 1998Phillips 2000) Anomalously low erosion rates using this method can be produced fromthe inheritance of cosmogenic nuclides from old soils incorporated into colluviumwhile bioturbation can produce depth profiles of cosmogenic nuclide concentration thatare very similar to those associated with rapid soil accumulation Fortunately thedistinctive profile produced through the rapid radioactive decay of in situ-produced14C when coupled with measurements of stable (eg 21Ne) or longer-lived isotopes(eg 10Be) can resolve the effects of both bioturbation and inheritance (Phillips 2000)The potential for cosmogenic isotope data to elucidate specific processes operating insoils on hillslopes especially when combined with other techniques has beenillustrated by Heimsath et al (2002) They used cosmogenic nuclide concentrations of10Be and 26Al to measure the overall downslope flux of soil material in combinationwith single-grain OSL dating to track the movement of individual quartz grains inorder to quantify the grain-scale mechanisms involved in the process of soil creep
VI Palaeoaltimetry
A fundamental difficulty in testing models of long-term landscape development is thelack of data on land surface palaeoelevation Without such data it is not possible toquantify changes in topography (in terms of elevation with respect to the geoid) overtime and therefore test this key component of landscape evolution models Sincecosmogenic nuclide production rates are a function of altitude ndash or more strictlyatmospheric pressure ndash accumulation is sensitive to changes in the elevation of a sampleduring exposure (Lal 1991) Inferring palaeoaltimetry from measured concentrations ofcosmogenic nuclides is therefore an exciting possibility (Gosse and Stone 2001) buttrue palaeoaltimetry requires independent data on the exposure age and erosion rate ofa sample since only by constraining these two unknowns can a change in surfaceelevation of a sample since it was first exposed be calculated Nonetheless it is possibleto evaluate particular combinations of surface exposure age and elevation changeduring the period of exposure Such an application has been used in the TransantarcticMountains Antarctica to test the assertion of substantial surface uplift of supposed latePliocene age Sirius Group glacial deposits and associated landscape elements at rates ofup to 1000 m Mandash1 over the past ~3 Ma (Brown et al 1991 Brook et al 1995a Ivy-Ochset al 1995 Bruno et al 1997 Schaumlfer et al 1999 Van der Wateren et al 1999) Thecosmogenic data can be interpreted as showing that either the Sirius Group deposits areof late Pliocene age or there has been substantial surface uplift over the past 3 Ma butnot both In other words the cosmogenic data provide a one-way test since within therelevant timescale high cosmogenic nuclide concentrations are incompatible with high
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
ndashndashndashndash 2002 The timing of the Last GlacialMaximum in Australia Quaternary ScienceReviews 21 159ndash73
Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
ndashndashndashndash 2002 Cosmogenic exposure and erosionhistory of Australian bedrock landformsGeological Society of America Bulletin 114787ndash803
Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
Bierman PR Gillespie AR and Caffee MW1995 Cosmogenic ages for earthquakerecurrence intervals and debris flow fandeposition Owens Valley California Science270 447ndash50
Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
Bourlegraves DL Braucher R Brown ETKalvoda J and Mercier JL 2002 YoungerDryas glacial expansion in the discontinuouslyglaciated area of Western and Central EuropeGeochimica et Cosmochimica Acta 66 S1 A98
Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
28 Geomorphological applications of cosmogenic isotope analysis
surface uplift rates whereas low concentrations do not require high surface uplift rates(because of the possibility of erosion reducing cosmogenic nuclide concentrations)(Brook et al 1995a)
Incorporating the effect of surface uplift increases apparent exposure times and thiseffect has been used to reconcile apparent differences between independent ageconstraints and cosmogenic exposure age estimates (Schaumlfer et al 1999 Kober et al2002) More accurate palaeoaltimetry from cosmogenic nuclide data in the future willrequire a better understanding of the atmospheric pressurendashaltitude relationship forproduction than is currently available (Gosse and Stone 2001) but will also requireunusual circumstances where the exposure history is independently constrained
VII Facilities for cosmogenic isotope analysis
The future expansion of applications of cosmogenic isotope analysis to geomorphologyand Quaternary science will depend to a significant extent on the availability offacilities for sample preparation and isotope measurement There are a growingnumber of such facilities worldwide with a concentration in the USA but includingAustralia Canada France Germany Japan and Switzerland In the UK there arededicated AMS target preparation laboratories for 10Be26Al and 36Cl in theDepartment of Geography at Edinburgh University but the widespread adoption ofcosmogenic isotope analysis in the UK as elsewhere will require a substantial increasein target preparation capability Sample preparation for the stable noble gas cosmogenicisotopes is less demanding and can be accomplished with standard laboratory facilities
In terms of the measurement of cosmogenic isotopes the high-sensitivity noble gasmass spectrometres capable of measuring 3He and 21Ne are relatively widely availablebut there are difficulties in using such machines where they have also been used formeasuring irradiated samples for 40Ar39Ar dating and the number of machinesdedicated to cosmogenic 3He and 21Ne is limited For the measurement of cosmogenicradioisotopes the tandem electrostatic accelerators most commonly used range inmaximum terminal voltage from less than 3 MV to 16 MV The lower voltage accelera-tors (~3 MV or less) are commonly used routinely for 14C but they can also be used tomeasure 10Be and 26Al Intermediate-sized machines (5ndash9 MV) can potentially measurethe full range of cosmogenic isotopes although the higher energies available from thelargest machines (10 MV or more) are particularly advantageous for the measurementof 36Cl (Fifield 1999) With a maximum terminal voltage of 5 MV the JointInfrastructure Fund (NERC)-financed AMS at the Scottish Universities EnvironmentalResearch Centre AMS Facility East Kilbride is in the intermediate category and willhave a capability across the range of cosmogenic isotopes commonly used in Earth andenvironmental science applications Although there are currently over 40 AMS facilitiesworldwide (Tuniz et al 1998) several specialize in radiocarbon dating and relativelyfew currently undertake significant numbers of measurements across a range ofcosmogenic isotopes for Earth and environmental science applications (Table 4)
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
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Bell JW Brune JN Liu T Zreda M and
Yount JC 1998 Dating precariously balancedrocks in seismically active parts of Californiaand Nevada Geology 26 495ndash98
Belton DX Brown RW Kohn BP and FinkD 2000 The first quantitative erosion rateestimates from lsquo the oldest persisting landforms in the world rsquo Geological Society ofAustralia Abstracts 58 24ndash28
Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
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Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
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Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
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ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 29
Table 4
AMS facilities invo
lved
in the
mea
suremen
t of cosm
ogen
ic isotop
es for Earth and
env
iron
men
tal s
cien
ce applic
ations
Facility
VT(M
V)
Principa
lCom
men
tsco
smog
enic isotope
smea
sured
Acc
elerator Lab
oratory ANU
155
10Be 14 C
26 A
l 36Cl
High vo
ltage acc
elerator w
ith an espe
cially goo
d capa
bility for 36Cl
Can
berra Australia
Expe
rien
ce w
ith env
iron
men
tal an
d geom
orph
ic app
lications
AMS Facility
510Be 14 C
26 A
l 36Cl
Ded
icated
to Earth and
env
iron
men
tal scienc
e ap
plications
SUER
C Ea
st Kilb
ride
UK
Gif-sur-Yve
tte Tan
detron
310Be 26 A
lUsed for several ap
plications employ
ing
10Be
Acc
elerator F
ranc
e
CAMS U
CLLN
L Califo
rnia
1010Be 14 C
26 A
lA facility w
ith a high-vo
ltage AMS that has produ
ced a large qu
antity of
USA
10Be an
d 26Al mea
suremen
ts and
has w
orke
d with
a w
ide rang
e of
colla
borators
ANTA
RES
ANST
O Lu
cas
1010Be 14 C
26 A
lA facility w
hich
has becom
e sign
ifica
ntly in
volved
in ge
omorph
olog
ical
Heigh
ts A
ustralia
and Qua
ternary scienc
e ap
plications since
the mid-199
0s
PRIM
E La
b Purdu
e8
10Be 14 C
26 A
l 36Cl
A facility w
hich
has w
orke
d with
a diverse ran
ge of co
llabo
rators both
Unive
rsity U
SAwith
the
USA
and
elsew
here
NSF
-Arizo
na AMS Facility
25
10Be 14 C
A m
ajor 14 C
facility tha
t ha
s be
en inv
olved in develop
ing the ap
plication
Unive
rsity
of A
rizo
na USA
of in
situ
-produ
ced
14C
VER
A V
ienn
a3
14C 26 A
l Prim
arily
kno
wn for 14C m
easuremen
ts
Austria
ETHPSI AMS Facility
610Be 14 C
26 A
l 36Cl
One
of the
first fac
ilitie
s to be invo
lved
in a rang
e of geo
morph
olog
ical
Zurich Switz
erland
and Qua
ternary scienc
e ap
plications
Not
es T
he listing is not exh
austive Fac
ilitie
s un
dertak
ing mea
suremen
ts of 1
4 C only are no
t inc
lude
d V
T m
axim
um terminal voltage A
NST
O A
ustralian
Nuc
lear Scien
ce and
Techn
olog
y Organ
isation ANTA
RES
Australian Nationa
l Tan
dem Accelerator fo
r App
lied Research ANU A
ustralian Nationa
lUnive
rsity
CAMS C
entre for AMS ETH
PSI S
wiss Fede
ral Institu
te of Techn
olog
yPaul Sch
errer Institu
te NSF N
ationa
l Scienc
e Fo
unda
tion PRIM
E La
bPu
rdue
Rare Isotop
e Mea
suremen
t La
boratory U
CLLN
L U
niversity
of C
alifo
rniaLaw
renc
e Liverm
ore Nationa
l Lab
oratory SUER
C Sc
ottish Universities
Environm
ental R
esearch Cen
tre VER
A V
ienn
a En
vironm
ental R
esea
rch Acc
elerator
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
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Ballantyne C Stone JOH and Fifield LK1998 Cosmogenic Cl-36 dating of postglaciallandsliding at the Storr Isle of Skye ScotlandThe Holocene 8 347ndash51
Barnard PL Owen LA Sharma MC andFinkel RC 2001 Natural and human-inducedlandsliding in the Garhwal Himalaya ofnorthern India Geomorphology 40 21ndash35
Barrows TT Stone JO Fifield LK andCresswell RG 2001 Late Pleistoceneglaciation of the Kosciuszko Massif SnowyMountains Australia Quaternary Research 55179ndash89
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Bierman PR 1994 Using in situ producedcosmogenic isotopes to estimate rates oflandscape evolution a review from thegeomorphic perspective Journal of GeophysicalResearch 99 13 885ndash96
Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
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Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
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Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
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Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
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Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
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Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
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Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
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Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
30 Geomorphological applications of cosmogenic isotope analysis
VIII Conclusions and future directions
Over the past decade there has been a remarkable growth in applications of cosmogenicisotope analysis in geomorphology and Quaternary science This has arisen very largelyfrom the capability to provide chronological constraints where none were possiblebefore both in terms of the timescales that can be addressed and because the techniquecan be applied to a range of minerals that are virtually ubiquitous on the Earthrsquossurface However this is still a rapidly developing technique and there are excitingprospects for the immediate future
One of these which underpins all applications of cosmogenic isotope analysis isimproved data on production rates and a better understanding of the spatial andtemporal factors that control them The importance of establishing a community-wideconsensus on cosmogenic isotope production rates used in the estimation of exposureages and denudation rates is now regarded as a major priority with the ultimateobjective of producing cosmogenic exposure ages with errors of 5 or less Coupledwith the analysis of a larger number of samples for a particular problem and themeasurement of several isotopes in the same sample this greater accuracy will providethe kind of tight chronological constraints necessary to answer key questions in recentEarth history
Another area of active research involves muon production (Heisinger et al 2002a bc) The greater attenuation length of muon interactions compared with spallation meansthat muogenic production requires more time to reach secular equilibrium with respectto losses from denudation and radioactive decay Consequently muogenic productionis less sensitive to short-timescale perturbations in denudation and therefore yieldsrates averaged over longer periods of time than the spallation-produced componentThis opens the possibility of comparing denudation rates over different timescales fromvertical sequences of samples (Stone et al 1994 Brown et al 1995b Heisinger andNolte 2000)
The issue of how rates of denudation might vary over different timescales can betaken much further by combining cosmogenic isotope analysis with other techniquesthat address both shorter and longer time ranges (Kirchner et al 2001) Suchinformation has important practical implications since denudation rates overlsquocosmogenicrsquo timescales can provide a valuable benchmark for recent anthropogenicperturbations of drainage basins The multi-timescale approach has already beenapplied in the Nanga Parbat area of the western Himalayas where the rate of incisionof the Indus River estimated from cosmogenic exposure ages of strath terraces wascompared with longer-term denudation rates derived from fission-track ther-mochronology (Burbank et al 1996) The combination of cosmogenic isotope analysisand thermochronology has also been applied to landscapes in far less active tectonicsettings (Belton et al 2000 Cockburn et al 2000 Brown et al 2002) Such comparativestudies have to be undertaken with care when using site-specific sampling forcosmogenic isotope analysis given the much larger spatial scale to which ther-mochronology applies but sampling from key landscape elements such as escarpmentfaces and summits can be fruitfully integrated with data on regional patterns ofdenudation derived from thermochronology (Cockburn et al 2000)
Finally expanded applications of catchment-averaged denudation rates studies arealso likely in the future The ability to document the exposure transport and burial of
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
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ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
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Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 31
sediment in fluvial systems over timescales of 103ndash106 yr opens up a whole suite of pos-sibilities for developing an understanding of drainage basin processes over thetimescales relevant to significant landscape change (Granger 2002) Particularlyvaluable for addressing the more recent part of this time range will be the wider use ofin-situ-produced 14C (Jull et al 1989 1992 1994b Handwerger et al 1999 Lal and Jull2001) Recent technical advances (Lifton et al 2001 2002) are now making it possible topair this short-lived radioisotope with cosmogenic nuclides with much longer half-livesin order to provide far more sensitivity in the detection of complex exposure histories
Acknowledgements
We thank Bill Phillips and Arjun Heimsath for comments on the manuscript andacknowledge financial support from the Natural Environment Research Council(HAPCMAS) the Australian Research Council (HAPC) the Leverhulme Trust(HAPC) and the Carnegie Trust for the Universities of Scotland (MAS)
References
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Anderson RS Repka JL and Dick GS 1996Explicit treatment of inheritance in datingdepositional surfaces using in situ 10Be and26Al Geology 24 47ndash51
Anthony EY and Poths J 1992 3He surfaceexposure dating and its implications formagma evolution in the Potrillo volcanic fieldRio Grande Rift New Mexico USA Geochimicaet Cosmochimica Acta 56 4105ndash108
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Bierman P and Caffee M 2001 Slow rates ofrock surface erosion and sediment productionacross the Namib Desert and escarpmentsouthern Africa American Journal of Science 301326ndash58
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Bierman P and Gillespie A 1991 Range fires ndasha significant factor in exposure age determina-tion and geomorphic surface evolution Geology19 641ndash44
Bierman P and Steig EJ 1996 Estimating ratesof denudation using cosmogenic isotopeabundances in sediment Earth Surface Processesand Landforms 21 125ndash39
Bierman P and Turner J 1995 10Be and 26Alevidence for exceptionally low rates ofAustralian bedrock erosion and the likely
32 Geomorphological applications of cosmogenic isotope analysis
existence of pre-Pleistocene landscapesQuaternary Research 44 378ndash82
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Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
Briner JP and Swanson TW 1998 Usinginherited cosmogenic 36Cl to constrain glacialerosion rates of the Cordelleran ice sheetGeology 26 3ndash6
Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
Briner JP Kaufman DS Werner A CaffeeM Levy L Manley WF Kaplan MR andFinkel RC 2002 Glacier readvance during thelate glacial (Younger Dryas) in the AhklunMountains southwestern Alaska Geology 30679ndash82
Brook EJ and Kurz MD 1993 Surface-exposure chronology using in situ cosmogenic
3He in Antarctic quartz sandstone bouldersQuaternary Research 39 1ndash10
Brook EJ Kurz MD Ackert RP DentonGH Brown ET Raisbeck GM and Yiou F1993 Chronology of Taylor glacier advances inArena Valley Antarctica using in situcosmogenic 3He and 10Be Quaternary Research39 11ndash23
Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
Brook EJ Nesje A Lehman S Raisbeck Gand Yiou F 1996 Cosmogenic exposure agesalong a vertical transect in western Norwayimplications for the height of theFennoscandian Icesheet Geology 24 207ndash10
Brown ET Edmond JM Raisbeck GMYiou F Kurz MD and Brook EJ 1991Examination of surface exposure ages ofAntarctic moraines using in situ produced 10Beand 26Al Geochimica et Cosmochimica Acta 552269ndash83
Brown ET Brook EJ Raisbeck GM Yiou Fand Kurz MD 1992 Effective attenuationlengths of cosmic rays producing 10Be and 26Alin quartz implications for exposure age datingGeophysical Research Letters 19 369ndash72
Brown ET Bourlegraves DL Colin F Sanfo ZRaisbeck GM and Yiou F 1994 Thedevelopment of iron crust lateritic systems inBurkino Faso West Africa examined with insitu produced cosmogenic nuclides Earth andPlanetary Science Letters 124 19ndash33
Brown ET Stallard RF Larsen MCRaisbeck GM and Yiou F 1995a Denudationrates determined from the accumulation of site-produced 10Be in the Luquillo ExperimentalForest Puerto Rico Earth and Planetary ScienceLetters 129 193ndash202
Brown ET Bourlegraves DL Colin F RaisbeckGM Yiou F and Desgarceaux S 1995bEvidence for muon-induced production of 10Bein near-surface rocks from the CongoGeophysical Research Letters 22 703ndash706
Brown ET Bourlegraves DL Burchfiel BCQidong D Jun Li Molnar P RaisbeckGM and Yiou F 1998a Estimation of slip
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
Bruno LA Baur H Graf T Schluumlchter CSigner P and Wieler R 1997 Dating of SiriusGroup tillites in the Antarctic Dry Valleys withcosmogenic 3He and 21Ne Earth and PlanetaryScience Letters 147 37ndash54
Burbank DW Leland J Fielding EAnderson RS Brozovic RS Reid N andDuncan C 1996 Bedrock incision rock upliftand threshold hillslopes in the northwesternHimalayas Nature 379 505ndash10
Carson MA and Kirkby MJ 1972 Hillslopeform and process Cambridge CambridgeUniversity Press
Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
Chadwick OA Hall RD and Phillips FM1997 Chronology of Pleistocene glacialadvances in the central Rocky MountainsGeological Society of America Bulletin 1091443ndash52
Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
ndashndashndashndash 2001a Reply to Comment on scaling factorsfor production rates of in situ producedcosmogenic nuclides a critical reevaluation ByDesilets D Zreda M Lifton NA Earth andPlanetary Science Letters 188 289ndash98
ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
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Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
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Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
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Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
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42 Geomorphological applications of cosmogenic isotope analysis
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Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
32 Geomorphological applications of cosmogenic isotope analysis
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Bierman PR Marsella KA Patterson CDavis PT and Caffee M 1999 Mid-Pleistocene cosmogenic minimum age limitsfor pre-Wisconsin glacial surfaces in southwest-ern Minnesota and southern Baffin Island amultiple nuclide approach Geomorphology 2725ndash40
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Bowen DQ Phillips FM McCabe AMKnutz PC and Sykes GA 2002 New data forthe last Glacial Maximum in Great Britain andIreland Quaternary Science Reviews 21 89ndash101
Braucher R Bourlegraves DL Colin F Brown ETand Boulange B 1998a Brazilian lateritedynamics using in situ produced 10Be Earth andPlanetary Science Letters 163 197ndash205
Braucher R Colin F Brown ET BourlegravesDL Bamba O Raisbeck GM Yiou F andKoud JM 1998b African laterite dynamicssuing in situ produced 10Be Geochimica etCosmochimica Acta 62 1501ndash507
Braucher R Bourlegraves DL Brown ET ColinF Muller JP Braun JJ Delaune M EdouMinko A Lescouet C Raisbeck GM andYiou F 2000 Application of in situ producedcosmogenic 10Be and 26Al to the study oflateritic soil development in tropical foresttheory and examples from Cameroon andGabon Chemical Geology 170 95ndash111
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Briner JP Swanson TW and Caffee M 2001Late Pleistocene cosmogenic Cl-36 glacialchronology of the southwestern Ahklunmountains Alaska Quaternary Research 56148ndash54
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Brook EJ Brown ET Kurz MD AckertRP Raisbeck GM and Yiou F 1995aConstraints on age erosion and uplift ofNeogene glacial deposits in the TransantarcticMountains determined from in situ cosmogenic10Be and 26Al Geology 23 1063ndash66
Brook EJ Kurz MD Ackert RP RaisbeckG and Yiou F 1995b Cosmogenic nuclidesexposure ages and glacial history of lateQuaternary Ross Sea drift in McMurdo SoundAntarctica Earth and Planetary Science Letters131 41ndash56
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HAP Cockburn and MA Summerfield 33
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Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
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Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
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Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
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Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
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Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 33
rates in the southern Tien Shan using cosmicray exposure dates of abandoned alluvial fansGeological Society of America Bulletin 110 377ndash86
Brown ET Stallard RF Larsen MC BourlegravesDL and Raisbeck GM 1998b Determinationof predevelopment denudation rates of an agri-cultural watershed (Cayaguas River PuertoRico) using in-situ-produced Be-10 in riverborne quartz Earth and Planetary Science Letters160 723ndash28
Brown RW Cockburn HAP Kohn BPBelton DX Fink D Gleadow AJW andSummerfield MA 2002 Combining lowtemperature apatite thermochronology andcosmogenic isotope analysis in quantitativelandscape evolution studies Geochimica etCosmochimica Acta 66 S1 A106
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Cerling TE 1990 Dating geomorphic surfacesusing cosmogenic 3He Quaternary Research 33148ndash56
Cerling TE and Craig H 1994a Geomorpho-logy and in-situ cosmogenic isotopes AnnualReview of Earth and Planetary Science 22 273ndash317
ndashndashndashndash 1994b Cosmogenic 3He production ratesfrom 39 to 46 degrees latitude western USAand France Geochimica et Cosmochimica Acta 58249ndash55
Cerling TE Poreda RO and Rathburn SL1994 Cosmogenic 3He and 21Ne age of the BigLost River flood Snake River Plain IdahoGeology 22 227ndash30
Cerling TE Webb RH Poreda RJ RigbyAD and Melis TS 1999 Cosmogenic 3Heages and frequency of late Holocene debrisflows from Prospect Canyon Grand CanyonUSA Geomorphology 27 93ndash111
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Clapp EM Bierman PR Schick AP Lekach
J Enzel Y and Caffee M 2000 Sedimentyield exceeds sediment production in aridregion drainage basins Geology 28 995ndash98
Clapp EM Bierman PR Nichols KKPavich M and Caffee M 2001 Rates ofsediment supply to arroyos from uplanderosion determined using in situ producedcosmogenic Be-10 and Al-26 QuaternaryResearch 55 235ndash45
Clapp EM Bierman PR and Caffee M 2002Using 10Be and 26Al to determine sedimentgeneration rates and identify sediment sourceareas in an arid region drainage basinGeomorphology 45 89ndash104
Clark DH Bierman PR and Larsen P 1995Improving in situ cosmogenic chronometresQuaternary Research 44 367ndash77
Cockburn HAP and Summerfield MA 2000Landscape evolution in Namibia constrainingdenudation with in-situ cosmogenic nuclidesCommunications of the Geological Survey ofNamibia 12 403ndash408
Cockburn HAP Seidl MA andSummerfield MA 1999 Quantifyingdenudation rates on inselbergs in the centralNamib Desert using in situ-producedcosmogenic 10Be and 26Al Geology 27 399ndash402
Cockburn HAP Brown RW SummerfieldMA and Seidl MA 2000 Quantifyingpassive margin denudation and landscapedevelopment using a combined fission-trackthermochronology and cosmogenic isotopeanalysis approach Earth and Planetary ScienceLetters 179 429ndash35
Craig H and Poreda R 1986 Cosmogenic 3Hein terrestrial rocks The summit lavas of MauiNational Academy of Science Proceedings 831970ndash74
Davis PT Bierman PR Marsella KACaffee MW and Southon JR 1999Cosmogenic analysis of glacial terrains in theeastern Canadian Arctic a test for inheritednuclides and the effectiveness of glacialerosion Annals of Glaciology 28 181ndash88
Davis R and Schaffer OA 1955 Chlorine-36 innature Annals of the New York Academy of Science62 105ndash22
Desilets D Zreda M and Lifton NA 2001Comment on scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation By Tibor Dunai Earthand Planetary Science Letters 188 283ndash87
Dickin AP 1995 Radiogenic isotope geologyCambridge Cambridge University Press 490pp
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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ndashndashndashndash 2001b Influence of secular variation of thegeomagnetic field on production rates of in-situproduced cosmogenic nuclides Earth andPlanetary Science Letters 193 197ndash212
ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
Dunne J Elmore D and Muzikar P 1999Scaling factors for the rates of production ofcosmogenic nuclides for geometric shieldingand attenuation at depth on sloped surfacesGeomorphology 27 3ndash12
Elmore D and Phillips FM 1987 Acceleratormass spectrometry for measurement of long-lived radioisotopes Science 236 543ndash50
Eppes MC and Harrison JBJ 1999 Spatialvariability of soils developing on basalt flowsin the Potrillo volcanic field southern NewMexico prelude to a chronosequence studyEarth Surface Processes and Landforms 241009ndash24
Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
Fink D Middleton R Klein J and Sharma P1990 41Ca measurement by accelerator massspectrometry and applications NuclearInstruments and Methods in Physics Research B 4779ndash96
Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
Fleming A Summerfield MA Stone JOFifield K and Cresswell RG 1999Denudation rates for the southern Drakensbergescarpment SE Africa derived from in-situ-produced cosmogenic 36Cl initial resultsJournal of the Geological Society London 156209ndash12
Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
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Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
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Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
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Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
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Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
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Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
34 Geomorphological applications of cosmogenic isotope analysis
Dunai TJ 2000 Scaling factors for productionrates of in situ produced cosmogenic nuclidesa critical reevaluation Earth and PlanetaryScience Letters 176 157ndash69
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ndashndashndashndash 2002 Scaling factors for in-situ cosmogenicproduction an attempt to reach a workingconsensus Geochimica et Cosmochimica Acta 66S1 A200
Dunai T and Wijbrans JR 2000 Long-termcosmogenic 3He production rates (152 kandash135Ma) from 40Ar39Ar dated basalt flows at 29degrees N latitude Earth and Planetary ScienceLetters 176 147ndash56
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Fabel D and Harbor J 1999 The use of in-situproduced cosmogenic radionuclides inglaciology and glacial geomorphology Annalsof Glaciology 28 103ndash10
Fabel D Stone J Fifield LK and CresswellR 1997 Deglaciation of the Vestfold Hills EastAntarctica preliminary evidence fromexposure dating of three subglacial erratics InRicci CA editor The Antarctic region geologicalevolution and process Siena Terra AntarticaPublications 823ndash34
Fabel D Stroeven AP Harbor J Kleman JElmore D and Fink D 2002 Landscapepreservation under Fennoscandian ice sheetsdetermined from in situ produced 10Be and26Al Earth and Planetary Science Letters 201397ndash406
Fenton CR Webb RH Pearthree PACerling TE and Poreda RJ 2001
Displacement rates on the Toroweap andhurricane faults implications for Quaternarydowncutting in the Grand Canyon ArizonaGeology 29 1035ndash38
Fifield LK 1999 Accelerator mass spectrometryand its applications Reports on Progress inPhysics 62 1223ndash74
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Finkel RC and Suter M 1993 AMS in the EarthSciences techniques and applications Advancesin Analytical Geochemistry 1 1ndash114
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Froumlhlich K and Luumlbert J 1973 Uber dieMoumlglichkeit der Messung von Erosionsgesh-windigkeiten an oberflaumlchengesteinen mit dennatuumlrlichen Radionuckliden 41Ca und 39ArZeitschrift fuumlr Angewandte Geologie 19 550
Gilbert GK 1877 Report on the geology of theHenry Mountains (Utah) Washington DCUnited States Geological Survey
Gosse JC and Phillips FM 2001 Terrestrial insitu cosmogenic nuclides theory andapplication Quaternary Science Reviews 201475ndash560
Gosse JC and Stone JO 2001 Terrestrialcosmogenic nuclide methods passing mile-stones toward palaeo-altimetry Eos 82 82ndash89
Gosse JC and Willenbring J 2002 Glaciererosion factory using 26Al10Be soils and geo-morphology to study relief developmentGeochimica et Cosmochimica Acta 66 S1 A287
Gosse JC Evenson EB Klein J Lawn B andMiddleton R 1995a Precise cosmogenic 10Bemeasurements in western North Americasupport fort a global Younger Dryas coolingevent Geology 23 877ndash80
Gosse JC Klein J Evenson J Lawn B andMiddleton R 1995b 10Be dating of theduration and retreat of the last Pinedale Glacialsequence Science 268 1329ndash33
Gosse JC Reedy RC Harrington CD andPoths J 1996 Overview of the workshop onsecular variations in production rates ofcosmogenic nuclides on Earth Radiocarbon 38135ndash47
Granger DE 2002 Spatially averaged erosion
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
ndashndashndashndash 1997 Quaternary downcutting rate of theNew River Virginia measured from differen-tial decay of cosmogenic 26Al and 10Be in cave-deposited alluvium Geology 25 107ndash10
Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
Gualtieri L and Brigham-Grette J 2001 Theage and origin of the Little Diomede Islandupland surface Arctic 54 12ndash21
Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
Jull AJT Donahue DJ Linick TW andWilson GC 1989 Spallogenic 14C in high-altitude rocks and in Antarctic meteoritesRadiocarbon 31 719ndash24
Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 35
rates from cosmogenic nuclides in sedimentsten years later Geochimica et Cosmochimica Acta66 S1 A288
Granger DE and Muzikar PF 2001 Datingsediment burial with in situ-producedcosmogenic nuclides theory techniques andlimitations Earth and Planetary Science Letters188 269ndash81
Granger DE and Smith AL 2000 Datingburied sediments using radioactive decay andmuogenic production of 26Al and 10Be NuclearInstruments and Methods in Physics Research B172 822ndash26
Granger DE Kirchner JW and Finkel RC1996 Spatially averaged long-term erosionrates measured from in situ-producedcosmogenic nuclides in alluvial sediment TheJournal of Geology 104 249ndash57
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Granger DE Fabel D and Palmer AN 2001aPliocenendashPleistocene incision of the GreenRiver Kentucky determined from radioactivedecay of cosmogenic 26Al and 10Be inMammoth Cave sediments Geological Society ofAmerica Bulletin 113 825ndash36
Granger DE Riebe CS Kirchner JW andFinkel RC 2001b Modulation of erosion onsteep granitic slopes by boulder armouring asrevealed by cosmogenic 26Al and 10Be Earthand Planetary Science Letters 186 269ndash81
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Gualtieri L Glushkova O and Brigham-Grette J 2000 Evidence for restricted ice-extent during the last glacial maximum in theKoryak Mountains of Chukotka far easternRussia Geological Society of America Bulletin 1121106ndash18
Hallet B and Putkonen J 1994 Surface datingof dynamic landforms young boulders onageing moraines Science 265 937ndash40
Hancock GS Anderson RS Chadwick OAand Finkel RC 1999 Dating fluvial terraceswith 10Be and 26Al profiles application to theWind River Wyoming Geomorphology 2741ndash60
Handwerger DA Cerling TE and Bruhn RL1999 Cosmogenic 14C in carbonate rocksGeomorphology 27 13ndash24
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 1997 The soil production
function and landscape equilibrium Nature388 358ndash61
ndashndashndashndash 1999 Cosmogenic nuclides topographyand the spatial variation of soil depthGeomorphology 27 151ndash72
Heimsath AM Chappell J Dietrich WENishiizumi K and Finkel RC 2000 Soilproduction on a retreating escarpment insoutheastern Australia Geology 28 787ndash90
Heimsath AM Dietrich WE Nishiizumi Kand Finkel RC 2001a Stochastic processes ofsoil production and transport erosion ratestopographic variation and cosmogenic nuclidesin the Oregon Coast Range Earth SurfaceProcesses and Landforms 26 531ndash52
Heimsath AM Chappell J and Dietrich WE2001b Late Quaternary erosion in southeasternAustralia a field example using cosmogenicnuclides Quaternary International 83 169ndash85
Heimsath AM Chappell J Spooner NA andQuestiaux DG 2002 Creeping soil Geology30 111ndash14
Heisinger B and Nolte E 2000 Cosmogenic insitu production of radionuclides exposure agesand erosion rates Nuclear Instruments andMethods in Physics Research B 172 790ndash95
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Neumaier S Knie K Lazarev Vand Nolte E 2002a Production of selectedcosmogenic radionuclides by muons 1 Fastmuons Earth and Planetary Science Letters 200345ndash55
Heisinger B Lal D Jull AJT Kubik P Ivy-Ochs S Knie K and Nolte E 2002bProduction of selected cosmogenic radio-nuclides by muons 2 Capture of negativemuons Earth and Planetary Science Letters 200357ndash69
Heisinger B Lal D Jull AJT Kubik PWIvy-Ochs S Neumaier S Knie K LazarevV and Nolte E 2002c Production of selectedcosmogenic radionuclides by muonsGeochimica et Cosmochimica Acta 66 S1 A558
Hermanns RL Trauth MH Niedermann SMcWilliams M and Strecker MR 2000Tephrochronologic constraints on temporal dis-tribution of large landslides in northwestArgentina Journal of Geology 108 35ndash52
Hermanns RL Niedermann S VillanuevaGarcia A Sosa Gomez J and Strecker MR2001 Neotectonics and catastrophic failure ofmountain fronts in the southern intra-AndeanPuna Plateau Argentina Geology 29 619ndash23
Hetzel R Niedermann S Ivy-Ochs S KubikPW Tao M and Gao B 2002a 21Ne versus10Be and 26Al exposure ages of fluvial terraces
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
Ivy-Ochs S Schluumlchter C Kubik P Dittrich-Hannen B and Beer J 1995 Minimum 10Beexposure ages of early Pliocene for the TableMountain plateau and the Sirius Group atMount Fleming Dry Valleys AntarcticaGeology 23 1007ndash19
Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
Jackson J Ritz JF Siame L Raisbeck GYiou Y Norris R Youngson J and BennetE 2002 Fault growth and landscapedevelopment rates in Otago New Zealandusing in situ cosmogenic 10Be Earth andPlanetary Science Letters 195 185ndash93
Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
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Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
Klein J Middleton R and Tang H-Q 1982Modifications of an FN Tandem for quantita-tive measurements of 10Be Nuclear Instrumentsand Methods in Physics Research B 193 601ndash16
Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
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Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
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Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
36 Geomorphological applications of cosmogenic isotope analysis
the influence of crustal Ne in quartz Earth andPlanetary Science Letters 201 575ndash91
Hetzel R Niedermann S Tao M Kubik PIvy-Ochs S Gao B and Strecker MR 2002bLow slip rates and long-term preservation ofgeomorphic features in Central Asia Nature417 428ndash32
Hindmarsh RCA van der Wateren FW andVebers ALLM 1998 Sublimation of icethrough sediment in Beacon Valley AntarcticaGeografiska Annaler Series A Physical Geography80 209ndash19
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Ivy-Ochs S Schluumlchter C Kubik P Synal H-A Beer J and Kerschner H 1996 Theexposure age of an Egesen moraine at JulierPass Switzerland measured with thecosmogenic nuclides 10Be 26Al and 36Cl Eclogaeund Geologie Helvetica 89 1049ndash63
Ivy-Ochs S Schluumlchter C Prentice M KubikP and Beer J 1997 10Be and 26Al exposure agesfor the Sirius Group at Mount Fleming MountFeather and Table Mountain and the PlateauSurface at Table Mountain In Ricci CAeditor The Antarctic region geological evolutionand process Siena Terra Antartica Publications1153ndash58
Ivy-Ochs S Heuberger H Kubik PWKerschner H Bonani G Frank M andSchluumlchter C 1998 The age of the Koumlfelsevent Relative 14C and cosmogenic isotopedating of an early Holocene landslide in thecentral Alps (Tyrol Austria) Zeitschrift fuumlrGletscherkunde und Glazialgeologie 34 57ndash68
Ivy-Ochs S Schluumlchter C Kubik PW andDenton GH 1999 Moraine exposure datesimply synchronous Younger Dryas glacieradvance in the European Alps and in theSouthern Alps of New Zealand GeografiskaAnnaler Series A Physical Geography 81 313ndash23
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Jackson LE Phillips FM Shimamura K andLittle EC 1997 Cosmogenic 36Cl dating of theFoothills erratics train Alberta CanadaGeology 25 195ndash98
Jackson LE Phillips FM and Little EC 1999Cosmogenic 36Cl dating of the maximum limitof the Laurentide Ice Sheet in southwesternAlberta Canadian Journal of Earth Science 361347ndash56
James LA Fabel D Dahms D and Elmore D2002 Late Pleistocene glaciation in the north-western Sierra Nevada California QuaternaryResearch 57 409ndash19
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Jull AJT Wilson AE Burr GS Toolin LJand Donahue D 1992 Measurements ofcosmogenic 14C produced by spallation in highaltitude rocks Radiocarbon 34 737ndash44
Jull AJT Lal D Donahue DJ Mayewski PLorius C Raynaud D and Petit JR 1994aMeasurements of cosmic-ray-produced 14C infirn and ice from Antarctica NuclearInstruments and Methods in Physics Research B 92326ndash30
Jull AJT Lifton N Phillips WM andQuade J 1994b Studies of the production rateof cosmic ray produced 14C in rock surfacesNuclear Instruments and Methods in PhysicsResearch B 92 308ndash10
Kaplan MR Miller GH and Steig EJ 2001Low-gradient outlet glaciers (ice streams)drained the Laurentide ice sheet Geology 29343ndash46
Karhu JA Tschudi S Saarnisto M Kubik Pand Schluumlchter C 2001 Constraints for thelatest glacial advance on Wrangel Island Arcticocean from rock surface exposure dating Globaland Planetary Change 31 447ndash51
Kelly MA von Blanckenburg F Kubik PWand Schluumlchter C 2002 Surface exposure agesof high elevation glacial erosion landforms anattempt to date deglaciation of the Last GlacialMaximum ice cap in the western Swiss AlpsGeochimica et Cosmochimica Acta 66 S1 A392
Kirchner J Finkel RC Riebe C GrangerDE Clayton JL King JG and MegahanWF 2001 Mountain erosion over 10 yr 10 kyand 10 my timescales Geology 29 591ndash94
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Klein J Giegengack R Middleton RSharma P Underwood JR and Weeks RA1986 Revealing histories of exposure using insitu produced 26Al and 10Be in Libyan DesertGlass Radiocarbon 28 547ndash55
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 37
Klinger Y Avouac JP Abou Karaki NDorbath L Bourlegraves D and Reyss JL 2000Slip rate on the Dead Sea transform fault innorthern Araba valley (Jordan) GeophysicalJournal International 142 755ndash68
Kober F Schlunegger F Ivy-Ochs S andWeiler R 2002 The dependency of cosmogenicnuclides to climate and surface uplift intransient landscapes Geochimica etCosmochimica Acta 66 S1 A408
Kubik PW Ivy-Ochs S Schluumlchter CMasarik J and Frank M 1998 10Be and 26Alproduction rates deduced from an instanta-neous event within the dendro-calibrationcurve the landslide of the Koumlfels Otz ValleyAustria Earth and Planetary Science Letters 161231ndash41
Kurz MD 1986a Cosmogenic helium in aterrestrial igneous rock Nature 320 435ndash39
ndashndashndashndash 1986b In situ production of terrestrialcosmogenic helium and some applications togeochronology Geochimica et Cosmochimica Acta50 2855ndash62
ndashndashndashndash 1987 Erratum in situ production ofterrestrial cosmogenic helium and some appli-cations to geochronology Geochimica etCosmochimica Acta 51 1019
Kurz MD and Brook EJ 1994 Surfaceexposure dating with cosmogenic nuclides InBeck C editor Dating in exposed and surfacecontexts Albuquerque NM University of NewMexico Press 139ndash59
Kurz MD Colodner D Trull TW MooreRB and OrsquoBrien K 1990 Cosmic rayexposure dating with in situ producedcosmogenic 3He results from young Hawaiianlava flows Earth and Planetary Science Letters 97177ndash89
Lal D 1988 In-situ-produced cosmogenicisotopes in terrestrial rocks Annual Reviews inEarth and Planetary Science 16 355ndash88
ndashndashndashndash 1991 Cosmic ray labelling of erosionsurfaces in situ nuclides production rates anderosion models Earth and Planetary ScienceLetters 104 424ndash39
Lal D and Arnold JR 1985 Tracing quartzthrough the environment Proceedings of theIndian Academy of Science Earth and PlanetaryScience 94 1ndash5
Lal D and Jull AJT 1990 On determining iceaccumulation rates in the past 40000 yearsusing in-situ cosmogenic C-14 GeophysicalResearch Letters 17 1303ndash306
ndashndashndashndash 1992 Cosmogenic nuclides in ice sheetsRadiocarbon 34 227ndash33
ndashndashndashndash 2001 In-situ cosmogenic C-14 productionand examples of its unique applications instudies of terrestrial and extraterrestrialprocesses Radiocarbon 43 731ndash42
Lal D and Peters B 1967 Cosmic ray producedradioactivity on the Earth In Sitte K editorHandbuch der Physik XLVI2 (462) SpringerVerlag Berlin 551ndash612
Lal D Nishiizumi K and Arnold J 1987 In-situ-produced cosmogenic 3H 14C and 10Be fordetermining the net accumulation and ablationof ice sheets Journal of Geophysical Research 924947ndash52
Lal D Jull AJT and Donahue DJ 1990 Polarice ablation rates measured using in-situcosmogenic C-14 Nature 346 350ndash52
Laughlin AW Poths J Healy HA ReneauS and WoldeGabriel G 1994 Dating ofQuaternary basalts using the cosmogenic 3Heand 14C methods with implications for excess40Ar Geology 22 135ndash38
Leland J Reid MR Burbank DW Finkel Rand Caffee M 1998 Incision and differentialbedrock uplift along the Indus River nearNanga Parbat Pakistan Himalaya from 10Beand 26Al exposure age dating of bedrockstraths Earth and Planetary Science Letters 15493ndash107
Licciardi JM Kurz MD Clark PU andBrook EJ 1999 Calibration of cosmogenic 3Heproduction rates from Holocene lava flows inOregon USA and effects of the Earthrsquosmagnetic field Earth and Planetary ScienceLetters 172 261ndash71
Licciardi JM Clark PU Brook EJ PierceKL Kurz MD Elmore D and Sharma P2001 Cosmogenic 3He and 10Be chronologies ofthe late Pinedale northern Yellowstone ice capMontana USA Geology 29 1095ndash98
Lifton NA Jull AJT and Quade J 2001 Anew extraction technique and production rateestimate for in situ cosmogenic 14C in quartzGeochimica et Cosmochimica Acta 65 1953ndash69
Lifton N Pigati J Jull AJT and Quade J2002 Altitudinal variation of in situcosmogenic 14C production rates preliminaryresults from the Southerwestern USAGeochimica et Cosmochimica Acta 66 S1 A457
Liu BL Phillips FM Elmore D and SharmaP 1994 Depth dependence of soil carbonateaccumulation based on cosmogenic 36Cl datingGeology 22 1071ndash74
Liu BL Phillips FM Pohl MM and SharmaP 1996 An alluvial surface chronology basedon cosmogenic 36Cl dating Ajo Mountains(Organ Pip Cactus National Monument)
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
38 Geomorphological applications of cosmogenic isotope analysis
southern Arizona Quaternary Research 4530ndash37
Loosli H 1983 A dating method with argon-39Earth and Planetary Science Letters 63 51ndash62
Marchant DR Lewis AR Phillips WMMoore EJ Souchez RA Denton GHSugden DE Potter N and Landis GP 2002Formation of patterned ground andsublimation till over Miocene glacier ice inBeacon Valley southern Victoria LandAntarctica Geological Society of America Bulletin114 718ndash30
Marsella KA Bierman PR Davis PT andCaffee MW 2000 Cosmogenic Be-10 and Al-26 ages for the Last Glacial Maximum easternBaffin Island Arctic Canada Geological Societyof America Bulletin 112 1296ndash312
Marti K and Craig H 1987 Cosmic-ray-produced neon and helium in the summit lavasof Maui Nature 325 335ndash37
Masarik J 2002 Numerical simulation of in-situproduction of cosmogenic nuclides Geochimicaet Cosmochimica Acta 66 S1 491 1
Masarik J and Reedy RC 1995 Terrestrialcosmogenic-nuclides production systematicscalculated from numerical simulations Earthand Planetary Science Letters 136 381ndash95
Masarik J Frank M Schaumlfer JM and WielerR 2001 Correction of in situ cosmogenicnuclides production rates for geomagnetic fieldintensity variation during the past 800000years Geochimica et Cosmochimica Acta 652995ndash3003
McKean JA Dietrich WE Finkel RCSouthon JR Caffee MW 1993 Quantifi-cation of soil production and downslope creeprates from cosmogenic 10Be accumulations on ahillslope profile Geology 21 343ndash46
Miller GH Wolfe AP Steig EJ Sauer PEKaplan MR and Briner JP 2002 TheGoldilocks dilemma big ice little ice or lsquojustrightrsquo ice in the Eastern Canadian arcticQuaternary Science Reviews 21 33ndash48
Mitchell SG Matmon A Bierman PREnzel Y Caffee M and Rizzo D 2001Displacement history of a limestone fault scarpnorthern Israel from cosmogenic 36Cl Journal ofGeophysical Research 106 4247ndash64
Molnar P Brown ET Burchfiel C QidpongD Xianyue F Jun L Raisbeck GMJianbang S Zhangming W Yiou F andHuichuan Y 1994 Quaternary climate changeand the formation of river terraces acrossgrowing anticlines on the north flank of theTien Shan China The Journal of Geology 102583ndash602
Nichols KK Bierman PR Hooke RLClapp EM and Caffee M 2002 Quantifyingsediment transport on desert peidmonts using10Be and 26Al Geomorphology 45 105ndash25
Niedermann S Graf T Kim JS Kohl CPMarti K and Nishiizumi K 1994 Cosmic-ray-produced 21Ne in terrestrial quartz theneon inventory of Sierra Nevada quartzseparates Earth and Planetary Science Letters 125341ndash55
Nishiizumi K Lal D Klein J Middleton Rand Arnold JR 1986 Production of 10Be and26Al by cosmic rays in terrestrial quartz in situand implications for erosion rates Nature 319134ndash36
Nishiizumi K Winterer EL Kohl CP KleinJ Middleton R Lal D andArnold JR 1989Cosmic ray production rates of 10Be and 26Al inquartz from glacially polished rocks Journal ofGeophysical Research 94 17 907ndash15
Nishiizumi K Klein J Middleton R andCraig H 1990 Cosmogenic 10Be 26Al and 3Hein olivine from Maui lavas Earth and PlanetaryScience Letters 98 263ndash66
Nishiizumi K Kohl CP Shoemaker EMArnold JR Klein J Fink D andMiddletonR 1991a In-situ 10Be and 26Al exposure age atMeteor Crater Arizona Geochimica etCosmochimica Acta 55 2699ndash703
Nishiizumi K Kohl CP Arnold JR Klein JFink D and Middleton R 1991b Cosmic rayproduced 10Be and 26Al in Antarctic rocksexposure and erosion history Earth andPlanetary Science Letters 104 440ndash54
Nishiizumi K Kohl CP Arnold JR DornR Klein J Fink D Middleton R and LalD 1993 Role of in-situ cosmogenic nuclides10Be and 26Al in the study of diversegeomorphic processes Earth Surface Processesand Landforms 18 407ndash25
Nishiizumi K Finkel RC Klein J and KohlCP 1996 Cosmogenic production of 7Be and10Be in water targets Journal of GeophysicalResearch 101 22 225ndash32
Noller JS Sowers JM and Lettis WReditors 2000 Quaternary geochronology methodsand applications Washington DC AmericanGeophysical Union 582 pp
Oberholzer P Schaumlfer JM Baroni C Ivy-Ochs S Orombelli G Baur H and WielerR 2002 Limited Pleistocene glaciation in DeepFreeze Range Northern Victoria LandAntarctica derived from in situ cosmogenicnuclides Geochimica et Cosmochimica Acta 66 S1A565
Owen LA Gualtieri L Finkel RC Caffee
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 39
MW Benn DI and Sharma MC 2001Cosmogenic radionuclide dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 16555ndash63
Owen LA Finkel RC and Caffee MW2002a A note on the extent of glaciationthroughout the Himalya during the global LastGlacial Maximum Quaternary Science Reviews21 89ndash101
Owen LA Finkel RC Caffee MW andGualtieri L 2002b Timing of multiple lateQuaternary glaciations in the Hunza ValleyKarakoram Mountains northern PakistanDefined by cosmogenic radionuclide dating ofmoraines Geological Society of America Bulletin114 593ndash604
ndashndashndashndash 2002c Reply cosmogenic radionuclidesdating of glacial landforms in the LahulHimalya northern India defining the timing ofLate Quaternary glaciation Journal ofQuaternary Science 17 279ndash81
Perg LA Anderson RS and Finkel RC 2001Use of a new 10Be and 26Al inventory method todate marine terraces Santa Cruz CaliforniaUSA Geology 29 879ndash82
Phillips FM 2000 Muogenic nuclides a methodfor dating rapidly eroding landformsGeochimica et Cosmochimica Acta 66 S1 A599
Phillips FM and Bowen DQ 2002 Acomparison of cosmogenic chronologies fordeglaciation in western North America andEurope Geochimica et Cosmochimica Acta 66 S1A598
Phillips FM Leavy BD Jannick NOElmore D and Kubik PW 1986 The accumu-lation of cosmogenic chlorine-36 in rocks amethod for surface exposure dating Science231 41ndash43
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW and Sharma P 1990Cosmogenic chlorine-36 chronology for glacialdeposits at Bloody Canyon Eastern SierraNevada Science 248 1529ndash32
Phillips FM Zreda MG Smith SS ElmoreD Kubik PW Dorn RI and Roddy DJ1991 Age and geomorphic history of MeteorCrater Arizona from cosmogenic 36Cl and 14Cin rock varnish Geochimica et Cosmochimica Acta55 2695ndash98
Phillips FM Zreda MG Benson LVPlummer MA Elmore D and Sharma P1996 Chronology for fluctuations in LatePleistocene Sierra Nevada glaciers and lakes
Science 274 749ndash51Phillips FM Zreda MG Evenson EB HallRD Chadwick OA Sharma P 1997Cosmogenic 36Cl and 10Be ages of Quaternaryglacial and fluvial deposits of the Wind RiverRange Wyoming Geological Society of AmericaBulletin 109 1453ndash63
Phillips WM 2000 Estimating cumulative soilaccumulation rates with in situ producedcosmogenic nuclide depth profiles NuclearInstruments and Methods in Physics Research B172 817ndash21
ndashndashndashndash 2001 A review of cosmogenic nuclidesurface exposure dating new challenges forScottish geomorphology Scottish GeographicalJournal 117 1ndash15
Phillips WM McDonald EV Reneau SLand Poths J 1998 Dating soils and alluviumwith cosmogenic 21Ne depth profiles casestudies from the Pajarito Plateau New MexicoUSA Earth and Planetary Science Letters 160209ndash23
Phillips WM Sloan VF Shroder JF SharmaP Clarke M and Rendell HM 2000Asynchronous glaciation at Nanga Parbatnorthwestern Himalaya Mountains PakistanGeology 28 431ndash34
Poreda RJ and Cerling TE 1992 Cosmogenicneon in recent lavas from the Western UnitedStates Geophysical Research Letters 19 1863ndash66
Pratt B Burbank DW Heimsath A andOjhaT 2002 Impulsive alluviation during earlyHolocene strengthened monsoons centralNepal Himalaya Geology 30 911ndash14
Repka JL Anderson RS and Finkel RC1997 Cosmogenic dating of fluvial terracesFremont River Utah Earth and Planetary ScienceLetters 152 59ndash73
Reynolds RW Geist D and Kurz MD 1995Physical volcanology and structuraldevelopment of Sierra Negra Volcano Isabella-Island Galapagos Archipelago GeologicalSociety of America Bulletin 107 1398ndash410
Riebe CS Kirchner JW Granger DE andFinkel RC 2000 Erosional equilibrium anddisequilibrium in the Sierra Nevada inferredfrom cosmogenic 26Al and 10Be in alluvialsediment Geology 28 803ndash806
Riebe CS Kirchner JW and Granger DE2001a Quantifying quartz enrichment and itsconsequences for cosmogenic measurements oferosion rates from alluvial sediment andregolith Geomorphology 40 15ndash19
Riebe CS Kirchner JW Granger DE andFinkel RC 2001b Strong tectonic and weak
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
40 Geomorphological applications of cosmogenic isotope analysis
climatic control of long-term chemicalweathering Geology 29 511ndash14
ndashndashndashndash 2001c Minimal climatic control on erosionrates in the Sierra Nevada California Geology29 447ndash50
Ritz JF Brown ET Bourlegraves DL Philip HSchlupp A Raisbeck GM Yiou F andEnkhtuvshin B 1995 Slip rates along activefaults estimated with cosmic ray exposuredates applications to the Bogd Faults Gobi-Altai Mongolia Geology 23 1019ndash22
Sarda P Staudacher T Allegravegre CJ andLecomts A 1993 Cosmogenic neon andhelium at Reacuteunion measurement of erosionrate Earth and Planetary Science Letters 119405ndash17
Schaumlfer JM Ivy-Ochs S Wieler R Leya IBaur H Denton GH and Schluumlchter C1999 Cosmogenic noble gas studies in theoldest landscape on earth surface exposureages of the Dry Valleys Antarctica Earth andPlanetary Science Letters 167 215ndash26
Schaumlfer JM Baur H Denton GH Ivy-OchsS Marchant DR Schluumlchter C and WielerR 2000 The oldest ice on Earth in BeaconValley Antarctica new evidence from surfaceexposure dating Earth and Planetary ScienceLetters 179 91ndash99
Schaumlfer JM Tschudi S Zhao ZZ Wu XIvy-Ochs S Wieler R Baur H Kubik PWand Schluumlchter C 2002a The limited influenceof glaciations in Tibet on global climate over thepast 170000 yr Earth and Planetary ScienceLetters 194 287ndash97
Schaumlfer JM Ivy-Ochs S Denton GHSchluumlchter C Weiler R Kubik PW andSchlosser P 2002b Rise and fall of the LastGlacial Maximum Geochimica et CosmochimicaActa 66 S1 672
Schaller M von Blanckenburg F Hovius Nand Kubik PW 2001 Large-scale erosion ratesfrom in situ-produced cosmogenic nuclides inEuropean river sediments Earth and PlanetaryScience Letters 188 441ndash58
ndashndashndashndash 2002 Palaeo-erosion rate record in a 16 Materrace sequence of the Meuse river Geochimicaet Cosmochimica Acta 66 S1 673
Schildgen T Dethier DP Bierman P andCaffee M 2002 26Al and 10Be dating of latePleistocene and Holocene fill terraces a recordof fluvial deposition and incision Coloradofront range Earth Surface Processes andLandforms 27 773ndash87
Schroeder PA Melear ND Bierman PKashgarian M and Caffee M 2001 Apparentgibbsite growth ages for regolith in the Georgia
Piedmont Geochimica et Cosmochimica Acta 65381ndash86
Seidl MA Finkel RC Caffee MW HudsonGB and Dietrich WE 1997 Cosmogenicisotope analyses applied to river longitudinalprofile evolution problems and interpretationsEarth Surface Processes and Landforms 22195ndash210
Shanahan TM and Zreda M 2000 Chronologyof Quaternary glaciations in East Africa Earthand Planetary Science Letters 177 23ndash42
Shepard MK Arvidson RE Caffee MFinkel R and Harris L 1995 Cosmogenicexposure ages of basalt flows Lunar Cratervolcanic field Nevada Geology 23 21ndash4
Siame LL Bourlegraves DL Seacutebrier M BellierO Castano JC Araujo M Perez MRaisbeck GM and Yiou F 1997 Cosmogenicdating ranging from 20 to 700 ka of a series ofalluvial fan surfaces affected by the El Tigrefault Argentina Geology 25 975ndash78
Siame LL Bellier O Seacutebrier M BourlegravesDL Leturmy P Perez M and Araujo M2002 Seismic hazard reappraisal fromcombined structural geology geomorphologyand cosmic-ray exposure dating analyses theEastern Precordillera thrust system (NWArgentina) Geophysical Journal International 150241ndash60
Small EE Anderson RS Repka JL andFinkel R 1997 Erosion rates of alpine bedrocksummit surfaces deduced from in situ 10Be and26Al Earth and Planetary Science Letters 150413ndash25
Small EE Anderson RS and Hancock GS1999 Estimates of the rates of regolithproduction using 10Be and 26Al from an alpinehillslope Geomorphology 27 131ndash50
Srinivasan B 1976 Barites anomalous xenonfrom spallation and neutron-induced reactionsEarth and Planetary Science Letters 106 87ndash102
Stanford SD Seidl MA and Ashley GM2000 Exposure ages and erosional history of anupland planation surface in the US AtlanticPeidmont Earth Surface Processes and Landforms25 939ndash50
Staudacher T and Allegravegre CJ 1993 Ages of thesecond caldera of Piton de la Fournaise volcano(Reacuteunion) determined by cosmic ray produced3He and 21Ne Earth and Planetary Science Letters119 395ndash404
Steig EJ Wolfe AP and Miller GH 1998Wisconsinan refugia and the glacial history ofeastern Baffin Island Arctic Canada coupleevidence from cosmogenic isotopes and lakesediments Geology 26 835ndash38
Stone JO 2000 Air pressure and cosmogenic
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
HAP Cockburn and MA Summerfield 41
isotope production Journal of GeophysicalResearch 105 23753ndash59
ndashndashndashndash 2002 Calibration and scaling of cosmogenicnuclides production rates Geochimica etCosmochimica Acta 66 S1 746
Stone J Allan GL Fifield LK Evans JMand Chivas AR 1994 Limestone erosion mea-surements with cosmogenic 36Cl in calcite ndashpreliminary results from Australian NuclearInstruments and Methods in Physics Research B 92311ndash16
Stone J Lambeck K Fifield LK Evans JMand Cresswell RG 1996 A Lateglacial age forthe Main Rock Platform Western ScotlandGeology 24 707ndash10
Stone JOH Evans JM Fifield LK AllanGL and Cresswell RG 1998a Cosmogenicchlorine-36 production in calcite by muonsGeochimica et Cosmochimica Acta 62 433ndash54
Stone JO Ballantyne CK and Fifield LK1998b Exposure dating and validation ofperiglacial weathering limits northwestScotland Geology 26 587ndash90
Stone JO Balco G Sugden DE CaffeeMW Siddoway C Cowdery S and Sass L2002 103ndash106 year history of the West Antarcticice sheet Geochimica et Cosmochimica Acta 66S1745
Stroeven AP Fabel D Hattestrand C andHarbor J 2002 A relict landscape in the centreof the Fennoscandian glaciation cosmogenicradionuclide evidence of tors preservedthrough multiple glacial cycles Geomorphology44 145ndash154
Sugden DE Marchant DR Potter N JrSouchex R Denton GH Swisher CC andTison J-L 1995 Miocene glacier ice in BeaconValley Antarctica Nature 376 412ndash16
Summerfield MA Stuart FM CockburnHAP Sugden DE Denton GH Dunai Tand Marchant DR 1999a Long-term rates ofdenudation in the Dry Valleys TransantarcticMountains southern Victoria Land Antarcticabased on in-situ produced cosmogenic 21NeGeomorphology 27 113ndash29
Summerfield MA Sugden DE DentonGH Marchant DR Cockburn HAP andStuart FM 1999b Cosmogenic data supportprevious evidence of extremely low rates ofdenudation in the Dry valleys region southernVictoria Land Antarctica In Smith BJWhalley WB and Warke PA editors Uplifterosion and stability perspectives on longtermlandscape development London GeologicalSociety of London Special Publications 162255ndash67
Taylor PJ and Mitchell WA 2002 Commentcosmogenic radionuclides dating of glaciallandforms in the Lahul Himalaya northernIndia defining the timing of Late Quaternaryglaciation Journal of Quaternary Science 17277ndash78
Trull TW Kurz MD and Jenkins WJ 1991Diffusion of cosmogenic 3He in olivine andquartz ndash implications for surface exposuredating Earth and Planetary Science Letters 103241ndash56
Trull TW Brown ET Marty B RaisbeckGM and Yiou F 1995 Cosmogenic 10Be and3He accumulation in Pleistocene beach terracesin Death Valley California USA Implicationsfor cosmic-ray exposure dating of youngsurfaces in hot climates Chemical Geology 119191ndash207
Tschudi S Ivy-Ochs S Schluumlchter C KubikP and Rainio H 2000 Be-10 dating of YoungerDryas Salpausselka I formation in FinlandBoreas 29 287ndash93
Tuniz C Bird JR Fink D and Herzog GF1998 Accelerator mass spectrometry ultrasensitveanalysis for global science Boca Raton FL CRCPress 371 pp
Van der Wateren FM and Dunai TJ 2001 LateNeogene margin denudation history ndashcosmogenic measurements from the centralNamib Desert Global and Planetary Change 30271ndash307
Van der Wateren FM Dunai TJ Van BalenRT Klas W Verbers ALLM Passchier Sand Herpers U 1999 Contrasting Neogenedenudation histories of different structuralregions in the Transantarctic Mountains riftflank constrained by cosmogenic isotope mea-surements Global and Planetary Change 23145ndash72
Van der Woerd J Ryerson FJ Tapponier PGaudemer Y Finkel R Meriaux ASCaffee M Guoguang Z and Qunlu H 1998Holocene left-slip rate determined bycosmogenic surface dating on the Xidatansegment of the Kunlun fault (Qinghai China)Geology 26 695ndash98
Van der Woerd J Tapponier P Ryerson FJMeriaux A-S Mayer B Gaudemer YFinkel RC Caffee MW Guoguang Z andZhiqin X 2002 Uniform postglacial slip-ratealong the central 600 km of the Kunlun Fault(Tibet) from 26Al 10Be and 14C dating of riseroffsets and climatic origin of the regionalmorphology Geophysical Journal International148 356ndash88
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
42 Geomorphological applications of cosmogenic isotope analysis
Weissel JK and Seidl MA 1998 Inlandpropagation of erosional escarpments and riverprofile evolution across southeast Australianpassive continental margin In Tinkler KJ andWohl EE editors Rivers over rock fluvialprocesses in bedrock channels AGU GeophysicalMonograph Series 107 Washington DCAmerican Geophysical Union 189ndash206
Wells SG McFadden LD Poths J andOlinger CT 1995 Cosmogenic 3He surfaceexposure dating of stone pavements implica-tions for landscape evolution in desertsGeology 23 613ndash16
Zehfuss PH Bierman PR Gillespie ARBurke RM and Caffee MW 2001 Slip rateson the Fish Springs fault Owens ValleyCalifornia deduced from cosmogenic 10Be and26Al and soil development on fan surfacesGeological Society of America Bulletin 113 241ndash55
Zimmerman SG Eveson EB Gosse JC andErskine CP 1994 Extensive boulder erosionresulting from a range fire on the Type-PinedaleMoraines Fremont Lake Wyoming QuaternaryResearch 42 255ndash65
Zreda M and Noller JS 1998 Ages of
prehistoric earthquakes revealed by cosmo-genic chlorine-36 in a bedrock fault scarp atHebgen Lake Science 282 1097ndash99
Zreda M and Phillips FM 1995 Insights intoalpine moraine development from cosmogenic36Cl build up dating Geomorphology 14 149ndash56
ndashndashndashndash 2000 Cosmogenic nuclides build-up insurficial materials In Noller JS Sowers JMand Lettis WR editors Quaternary geochronol-ogy methods and applications AGU ReferenceShelf Series Washington DC AmericanGeophysical Union 61ndash76
Zreda M Phillips FM Kubik PW Sharma Pand Elmore D 1993 Cosmogenic 36Cl datingof a young basaltic eruption complex LathropWells Nevada Geology 21 57ndash60
Zreda MG Phillips FM and Elmore D 1994Cosmogenic 36Cl accumulation in unstablelandforms 2 Simulations and measurement oneroding moraines Water Resources Research 303127ndash36
Zreda M England J Phillips F Elmore Dand Sharma P 1999 Unblocking of the NaresStrait by Greenland and Ellesmere ice sheetretreat 10000 years ago Nature 398 139ndash42
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