sea-level change: past, present, future

View of NY harbor from the !JOIDES Resolution in an ice-free world (64 m rise)!

Onshore ODP-EAR-ICDP!Legs 150X & 174AX !

Kenneth G. Miller (& friends)!Dept. Earth & Planetary Sci., Rutgers University, AAPG Distinguished Lecturer!

ODP/IODP!Legs 150 & 174A!

Sea-level Change: Past, Present, Future!

My shore house!Dec. ‘91 nor’easter!

NJ shallow shelf!IODP Exp 313, L/B Kayd!

2008 (Miller)

3 ft sea-level rise ~2100 CE 1 ft sea-level rise ~2040 CE

Oct. 31, 2012 (AP) N

N

N N

Ship Bottom, Long Beach Island, NJ

http://slrviewer.rutgers.edu

Causes of global average sea-level change Global average sea level (=eustasy) raised by:

•  Temperature: warming expands seawater (less dense) •  Ice volume: melt ice (mountain glaciers & ice sheets) •  Ocean volume (ocean crust production, etc.; 107 yr)

Department of Earth and Planetary Sciences

Causes of relative sea-level change Regional sea level:

1) Subsidence (sinking) or uplift tectonics (e.g., Alaska uplift) includes glacial isostatic adjustment (GIA)

2) Oceanographic effects (e.g., El Nino, Gulf Stream changes)

Local sea level: Compaction due to natural processes & water or oil extraction


Un-Vailing eustasy: An ad-Haq hypothesis?!Vail et al.(1977)! Haq et al. (1987)!

400 m! m!!

160 m m!!

How is sea-level change reconstructed?!

1)  Date the record!!

2)  Determine changes in water depth (local)!

!!!3)  Remove local and regional subsidence/uplift !

Challenge!

Artful!

Reference frame?!

Geologic approaches studying sea-level change!

•  Drill reefs on atolls and uplifted terraces!e.g., Barbados, Tahiti, N. Guinea, Sunda shelf, Enewetak!

•  Drill continental margins!e.g., IODP New Jersey offshore & onshore, !New Zealand, !Bahamas, !NE Australia!

COSODII (1987), Sea level workshop (1990), ODP-SLWG (1992), IODP-ICDP-DOSECC workshop (2008) !

•  Drill deep-sea sections glacioeustatic proxy!e.g., δ18O, Mg-Ca with astronomical time control!

D/V Ranger!

JOIDES Resolution!

L/B Kayd!Sandy Hook NJ!Oct. 2014!

Sea-level records (Miller et al., 2011)!

Above: scaled deep sea δ18O!Left: backstripped onshore core!

NJ/MAT sea-level transect (Legs 150, 150X, 174A, 174AX, 313)!Develop eustatic estimates & evaluate stratigraphic response!

excellent seismic grid; simple tectonics (thermal);!excellent age control (Sr-isotope, bio-, magneto-stratigraphy); paleodepth control (litho- & biofacies); previous data!

29!27 28!

Why NJ: !

New Jersey outcrop sequence boundary!

Campanian/Maastrichtian unconformity!Matawan, NJ�

Sequence: stratigraphic unit of relatively conformable, genetically related strata bounded by unconformities and correlative surfaces associated with baselevel lowering (tectonic & eustatic)!

Identifying marine sequence boundaries in cores!Physical evidence

•  Sharp unconformable contacts •  Lag gravels, phosphorites •  Shell beds/hash •  Rip-up clasts •  Extensive burrowing and bioturbation •  Geophysical log characteristics •  Overstepping of lithofacies successions •  Facies succession (model dependent) •  Dramatic paleodepth changes

Must show geographic distribution (not local surface)

Temporal Hiatuses •  Sr-isotopic stratigraphy •  Biostratigraphy (e.g., planktonic

foraminiferal zones)

Oligocene!(~ 26.6 Ma)!

Mid-Miocene!(M4)!(18.0-18.4 Ma)!

Seismic profiles image unconformities!Red lines are seismic unconformities recognized by onlap,

downlap, erosional truncation, and toplap!

Sequence boundaries = sea-level falls!

Sequence boundaries subdivide onshore record!14 Miocene, 8 Oligocene, 12 Eocene, 7 Paleocene 15-17 Late K!!

Offshore prograding Miocene sequences!

Expedition 313! M27 M28 M29!

Onshore: Predictable facies!

Characteristics!• erosional boundaries!• shoaling upwards,

paleodepth from litho- and biofacies!

• each ends near shore!• ages Sr-isotopic dating &

biostrat. ±0.3-0.5 Ma !• ~1.5 Ma duration!

Lower Miocene example!onshore sequences, !

Leg 150X Cape May, NJ!!

Onshore !sequences!

T1T0 T3 T4 T5T2

R1

TheoreticalThermal

Subsidence<-

Dept

h

T0

T3

T4

T5

T1

T2

T0

T1

ObservedSedimentThickness

DecompactedSediment

Thickness, S*

T0

T1

FirstReduction

R1

T0

T1

equivalentbasin forsedimentthickness S*

paleo-waterdepth

T2 T2 T2

T0

T3

T1

T2

T3 T3

MeasuredSection

R1 =T.S.

ΔSL ρa -ρ

w+ a

ρ

ρa s*aρw

-S* - =ρρ

+ WD

T1T0 T3 T4 T5T2

Sea Level Change & Non-Thermal TectonicsHe

ight

->

ρa -ρ

wR2 = R1 - T.S. ΔSLρa

=

Backstripping Method for Determining Sea-Level

Backstripping: remove compaction, loading, thermal!

Slide from M. Kominz!

Benthic foraminifers:!Neritic zone!

Inner: 0-30 m ± 15!Middle: 30-100 m ± 30!Outer: 100-200 m ± 50!

Better relative error!

Paleowater Depth: Largest Error Source!Lithofacies:!

Excellent for shoreface to 20-30 m ± 5-10 m error !

Backstripping provides eustatic estimate!

Backstripping onshore NJ!!

1-D backstripping accounts for!•  compaction !•  loading (Airy)!•  thermal subsidence fit !McKenzie stretching !exponential curve!

!

2-D (Oligocene) accounts for !flexural loading !

!

Residual R2 eustatic estimate & non-thermal subsidence!

ρa - ρw

T.S. = Φ ρa ρs*ρ

a ρw

-ΔSL

ρwρa - ρw

+ WD - ΔSLS* - -

BACKSTRIPPING EQUATIONS

Φ = the basement response function to loadingS* = the decompacted sediment thicknessρ = densitya = asthenospherew = water∆SL = change in eustatic (global) sea-levelWD = paleo-water depth of the sediments

T.S. = tectonic subsidence, or the subsidence of the basin floor in water without any sediment load.

R1 = T.S. ρa ρs*ρ

a ρw

-ΔSL

ρρa - ρw

S* -+ a = + WD

R2 = R1 - T.S. ΔSLρa

=

Backstripped sea level New Jersey onshore R2!

Kominz et al. (2008) update of Miller et al. (2005)!!Thick black = best estimate,!Thin black = lowstand guestimates !Orange = error!!!Download data !!http://geology.rutgers.edu/people/faculty/19-people/faculty/242-kenneth-g-miller!

•  late Pliocene-Recent: Antarctic and large, variable Northern Hemisphere ice 30-120 m sea-level!

!•  Oligocene-early Pliocene:

large, variable Antarctic ice ! 30-60 m sea-level changes!!•  Late Cretaceous-Eocene:

Ephemeral Antarctic ice 15-30 m sea-level changes!

δ18O and sea level 105-106 yr scale!

Large (>25 m), rapid (<1 Myr) sea-level changes only explained by glacioeustasy, yet high latitudes were warm!

Cretaceous-Eocene: An ice-free greenhouse? !

Left: An Ice-Free World: !Shoreline assuming 64 m higher sea level!

~15 Ma = modern, permanent EAIS!

Greenhouse ice sheets restricted to Antarctic interior !

Antarctic Ice Sheet!

~70 Ma, largest Cretaceous, 40 m!

~33 Ma, e. Oligocene, 55-80 m!

~92 & 96 Ma, big Cretaceous, 25 m!

~93 Ma, typical Cretaceous, 15 m!

Maps: models of Deconto & Pollard (2002) Sea-level: Miller et al. (2011)!

The Icehouse Cometh:!Heartbeat of the Greenhouse-Icehouse transition!

Animation courtesy of D. Pollard after DeConto and Pollard (2002)!!Beginning illustrates Greenhouse ice growth and decay (~3x CO2)!!End illustrates Oligocene Icehouse (<2.8 CO2 )!

!

Timing falls ± correct!!

Long-term 100 vs. 250 m!!

Myr-scale amplitudes 30-80 m, not 100+ m!!

Sahagian Russian platform backstripping overlaps & extends to Early Jurassic!!!

�It has been said that ours is the worst form of [sea-level curves] except all the others that have been tried.” Churchill, 1947

Comparison with Exxon estimates!

•  NJ sat high in Cretaceous due to subducting Farallon plate (Müller et al., Science, 2008; Moucha et al., EPSL, 2008; Spasojevic et a., GRL, 2008; Rowley et al., 2013)

•  estimate of 150 ± 50 m for Late Cretaceous peak

No such thing as a stable continent!

Kominz et al. (2008)!

Continental flooding & backstripped estimates !Late Cretaceous estimates!

NJ: 50-70 m (now 100 m)!Exxon: 250 m!Müller (2008): 175 m!Kominz Ridge: 45-365 m (230 m)!Scotian backstrip: 120 m !Continental flooding:!!Harrison (1990): 150 m!

Bond (1979): ~140 m (80-200 m) !QED: 150 ± 50 !Consistent with small changes!!in spreading rates!

Müller !

Miller et al. (2011)!!

Posted at http://geology.rutgers.edu/miller.shtml!

Scale δ18O to sea-level!Late Miocene ice volume

similar to today, δ18O 0.5‰ lower due to 2°C cooling!

0.1 ‰/10 m calibration!Miller et al. (2011) update using

Lisiecki & Raymo (2005) stack and 67:33 ice:temperature attribution !

δ18O and sea level 105-106 yr scale!

Deep-sea Mg/Ca paleotemperatures Mg/Ca δ18O + = Paleotemperature + δ18Osw

Cramer et al. (2011) smoothed > 2 Myr! δ18Osw / 0.1‰/10 m = water volume change in meters ~ eustasy!

Cramer et al. (2011)

Miller et al. (in prep.)!

Deep sea benthic foraminiferal δ18O records All astronomically tuned Cibicidoides records!

Pacific !Sites 574!

Pisias et al., 1985 ! 7 kyr rez!

!

Indian Site 751 this study 10 kyr rez

Atlantic Site 929

Pälike et al.,2006 4 kyr rez

Pacific Site 1218

Lear et al., 2004 40 kyr rez

Different scales reflect different bottom water temperatures, δ18sw Miller et al. (in prep.)!

Deep sea temperature estimates

δ18Obenthic normalized to Pacific values ~Pacific temperatures Temperature subtracted from δ18Obenthic -0.25‰/°C (Shackleton)

δ18Oseawater converted to sea level 0.1‰/10 m (Fairbanks and Matthews, 1977; deConto and Pollard, 2002; Pekar et al., 2002)


A deep sea δ18O/Mg-Ca based eustatic estimate

No tectonoeustatic correction

This scale may shift Miller et al. (in prep.)!

Deep sea versus NJ onshore eustatic estimate


No such thing as a stable continent

Moucha et al. (2008)

on

off

200 m change since 30

Ma Onshore

50 m different

IODP Ex. 313: NJ/Mid-Atlantic Transect!

Summer 2009!

Offshore Expedition 313: Example from Site 28

Miller et al. (2013a) Geosphere

Age control:!(Browning et al., 2013)!nannofossils!diatoms (Barron et al.)!dinocysts (McCarthy et al.)!Sr-isotopes (Browning et al.)!

Paleodepth: !benthic foraminifera! (Katz et al., 2013) + lithofacies! (Miller et al., 2013b)!!

!

mud

m-c sand

v-f

Onshore vs. offshore R2 offset: Moucha is right!

R2 = eustasy + non-thermal

tectonism

Offsets between R2 onshore and

offshore indicates non-

thermal tectonism

Onshore


Dynamic topo: modern view of arches, epeirogeny

Rowley et al. (2012)!!

Explains Yorktown problem!Pliocene marine in VA!

Upland gravels NJ !

-20

-15

-10

-5

0

5

10

15

20

25

2468101214 0

high sea levelrelative subsidence

Age, Ma

Langeley, VA

NJ hiatus

NJ eustatic estimate

Exmore, VA

low sea levelrelative uplift

Site 1308 N. Atlantic!

Integration of atoll, margin, deep-sea records!Pliocene ca. 3 Ma peak sea level 22±10 m CO2 ~400 ppm, !

global T = 1-2°C warmer (Miller et al., Geology, 2012)!

Eyreville, VA!

Enewetak Atoll!

Wanganui Basin!New Zealand!

�likely� (68%) peak sea-levels 17-27 m higher than modern �extremely likely� (95%)� was 12-32 m higher !

Purple: averages ±1 σ of ! Virginia (red points)! New Zealand (black line)! Enewetak (green points)! Mg-Ca δ18O!

Barbados Acropora palmata (fossil sunshine) !

!120 m ± 5 m lowstand!Last Glacial Maximum!Fairbanks, 1989, 1990)!

!MWP1A rate >40 m/1000 yr!

!(rates from Fairbanks, 1990; Stanford et al., 2006; Miller et

al., 2009; Dechamps et al., 2012; Abdul et al., submitted)!

Barbados ~ global average sea level !D

epth

(m)

Age (ka)

Δδ Ο

(‰)

18

Th/U Age

C Age14

120

110

100

90

80

70

60

50

40

30

20

10

0

1.1

1.0

0.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

1.2

161514131211109876543210 17 18 19 20

Younger DryasChronozone

after Fairbanks (1990)

last glaciation 120 m

7-5 ka, 2 mm/yr

Meltwater pulse 1B 36 mm/yr

Meltwater pulse 1A >40 mm/yr

11-7ka, 8 mm/yr

5-2 ka, 1 mm/yr; 0.75±0.25 mm/yr

!1st millenium 0 rise; Medieval Warm 2.3 inches/century (0.6 mm/yr); !

Little Ice Age ~0 rise; 20th century 7 inches/century (1.7 mm/yr)!!

!

Kemp et al. (2011)

Little ice age Roman

Warm Period

0.65

-0.65

Sea

leve

l fee

t

Is modern sea-level rise part of a natural cycle?

Medieval Warm Period


Global sea level is rising and accelerating Tide Gauges 1880-2006

6.7 inches per century 1.7 ± 0.4 mm/yr

Church & White (2006)

Satellite data 1993-2013 12 inches per century 3.2 ± 0.4 mm/yr http://sealevel.colorado.edu/


Why Is global sea level is rising today?

Thermal Expansion: Ocean has gained heat Warmer water is less dense

Global temperature increase explains about 1/3 modern rise

Melting Glaciers & Ice Caps Melting land ice raises sea

level, but not sea ice

Alpine

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

Why Is global sea level Is rising today?

.

~ 30% rise is due to melting mountain glaciers Prior to 2003, < 15% sea level rise was from

melting ice sheets, now greater (Cazenave & Le Cozanne, 2014)

How much sea level is stored in ice sheets? Greenland ~23 ft (7 m) W. Antarctica ~16 ft (5 m) E. Antarctica 170 ft (52 m)

Mountain glaciers

Change of surface elevation Pritchard et al. (2009)

IPCC (2001)

Length

Revised mass loss figures from ice sheets Mass loss from Greenland and West Antarctica appears to be accelerating

Shepherd et al. (2012)

National Research Council projections 2012

Scenario-based projections of global sea-level rise by 2100 of 2.7 ft (range 1.7-4.6 feet)


Global versus Regional Effects 12 inches/century = 3 mm/yr

global global

16 inches/century = 4 mm/yr

Mid-Atlantic tide gauges; blue = data, green = smoothed fit. Kopp (2013) & Miller et al. (2013)

Global average tide gauges (pink) 6.7 inches/century (1.7 mm/yr) Church & White (2006)

global


http://www.dreamstime.com/royalty-free-stock-photos-3d-people-seesaw-image15520048

GIA: Glacial Isostatic Adjustment Melting of ice sheets results in a regional adjustment:

sinking (blue) in some areas, uplift (red) in others


Ice sheet us

Fall (red) line separates bedrock & coastal plain

Bedrock sites NYC/Bayonne, Phil./Camden, Baltimore, D.C.

12 inches/century (3 mm/yr) = global + GIA regional

Coastal plain sites Sandy Hook–Norfolk 16-18 in./century (4.0-4.5 mm/yr) = global + regional + compaction

Regional vs. local sea level from tide gauges


~3 ~3.5 ~4 ~4.5

mm/yr

Miller et al. (2013c)

Future sea-level rise mid-Atlantic US


Miller et al. (2013)

Shore = Atlantic City, Cape May 43 cm by 2050, 103 cm by 2100 Bedrock = NYC, Phil., Baltimore, D.C.: 38 cm by 2050, 93 cm ft by 2100

Miller et al. (2013c)

Future sea-level rise mid-Atlantic US


Miller et al. (2013c) Shore = Atlantic City, Cape May 43 cm by 2050, 103 cm by 2100

Bedrock = NYC, Phil., Baltimore, D.C.: 38 cm by 2050, 93 cm ft by 2100

Effects of sea-level rise: Coastal flooding By 2100, a “5 to 10-yr storm” will have the flooding of a modern

“100-yr storm”

My house Dec. 1992 nor’easter

My block Sandy 4 PM

Typical nor’easter Nov. 8, 2012


Miller et al. (2013)

•  Late Cretaceous-Eocene (100-33 Ma): Ephemeral Antarctic ice sheets ~15-30 m sea-level changes!

•  Oligocene-early Pliocene (33-2.7 Ma): Large, variable Antarctic ice sheets 30-60 m sea-level changes!

•  Late Pliocene-Recent (2.5-0 Ma): Antarctic & Northern Hemisphere ice ages 30-120 m sea-level changes!

!

105-106 yr scale!

104 yr scale!•  Globally rising 5-2 ka, 0.75±0.25 mm/yr!•  Stable in the Common Era, last 2000 yr!•  20th century, 1.7 mm/y!•  Today, 3.2 mm/yr, largely anthropogenic!

Conclusions!

•  Long-term sea level 150 ± 50 m 100-60 Ma!107 yr scale!

Should I sell my shore house?!

Don�t sell: insure!!global >80 cm (2.4 ft) by 2100!NJ >-100 cm (>3 ft)!!

!!

View of NY harbor in an ice-free world (65 m rise)!

More beach erosion, rollback!More cost to replenish!Loss of marshland!Increased storm intensity?!What about those coming behind?!

Vanuatu!

Carteret Is.!

Tuvalu !

sea-level change: past, present, future

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