7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 1/11

Basin Analysis - Principles & ApplicationsFriday, May 17, 20133:25 PM

 LI!"#P!$%I M$!A'I#

 Lit(ostatic stress - t(e si)plest *ie+ o applied orces si)ple to t(e+ei(t o t(e o*erlyin roc. col/)nse*iatoric stresses - t(e dierence et+een t(e act/al stress and t(elit(ostatic stress is a tectonic contri/tion .no+n as de*iatoric stress Itcan e eit(er tensile or co)pressi*e In an elastic solid t(ere is a clear relations(ip et+een t(e stresses andres/ltant strains (e e4act relations(ip depends on )aterial properties.no+n as o/n6s )od/l/s and Poissons6s ratio (ere only one o t(eprincipal a4es is non-8ero, a /nia4ial state o stress is said to occ/r and

t(e relation et+een stress and strain is called !oo.e6s La+ I t(ere aret+o non-8ero co)ponents o principal stress, +e (a*e t(e conditionter)ed plane stress. In an analoo/s as(ion, uniaxial strain and planestrain reer to t(e coordinate syste) o principal strains

 (e endin )o*e)ent is related to t(e local radi/s o c/r*at/re y acoe9cient called fexural rigidity. 

 (e te)perat/re radient in a con*ectin /id s(o/ld e adiabatic, t(atis, t(e te)perat/re increase +it( dept( is ca/sed p/rely y co)pressiond/e to t(e o*erlyin roc. col/)n 'or)al stresses: t(ose t(at act perpendic/lar to a s/race#(ear stresses: t(ose t(at act parallel to t(e s/race

 (e press/re is t(e )ean *al/e o t(e nor)al stresses#train: deor)ation o a solid'or)al strain is si)ply t(e ratio o t(e c(ane in lent( o a solid to itsoriinal lent(#(ear strain is de;ned as one (al o t(e decrease in a ri(t anle in asolid +(en it is deor)ed

#%$## & #%AI' Isostacy: s/pport o t(e oceanic and continental plates y t(e )antlest(r/ (ydrostatic e</iliri/) =Arc(i)edes Principle>'o s(ear stresses e4ist on s/races oriented perpendic/lar to t(eprinciple a4es, and nor)al stresses in t(e principal a4is coordinatesyste) are .no+n as principal stresses

$lastic deor)ation:For relati*ely lo+ te)perat/res, press/res and applied orces,al)ost all solid )aterials e(a*e elastically (e relation et+eenstress and elastic strain is linear !o+e*er, at (i( te)perat/resand press/res or (i( le*els o stress roc.s do not e(a*eelastically

Fle4/re in t+o di)ensions:

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 2/11

1 Fle4/re res/lts ro) *ertical orces, (ori8ontal orces and tor</es?edin )o)ents> in co)ination !ori8ontal loads are co))onlynelected in eodyna)ical prole)s

2 (e endin )o*e)ent in t(is interation o t(e ;re =nor)al>stresses on cross-sections o t(e plate actin o*er t(e distance tot(e )idline o t(e plate (e endin )o*e)ent is related to t(elocal radi/s o c/r*at/re o t(e plate y a coe9cient called t(ee4/ral riidity Fle4/ral riidity is proportional to t(e c/e o t(eelastic t(ic.ness

3 A eneral e4/ral e</ation can e deri*ed +(ic( e4presses t(edeection o t(e plate in ter)s o t(e *ertical and (ori8ontal loads,endin )o)ent and e4/ral riidity (is e</ation can readily eadapted or /se in t(e st/dy o eoloical prole)s

 (e e4/re o t(e plate depends on its t(ic.ness, elastic properties andt(e nat/re o t(e applied load

!$A FL" !i( (eat o+ reions on continents: enerally correspond to acti*e*olcanic areas, reions o e4tensional tectonicsLo+ (eat o+ reions: continental collision 8onesIn areas de*oid o acti*e tectonics and */lcanicity, t(e (eat o+appears to e in*ersely correlated to ae o t(e roc.s (is can ee4plained y t(e decreasin a/ndance +it( ae o t(e radioacti*e(eat-prod/cin isotopes o /rani/), t(ori/) and potassi/)

-(e process o cond/ction and con*ection are dierin i)portance indierent 8ones In t(e lit(osp(ere (eat is transported pri)arily t(ro/(

cond/ction, +(ereas t(e )antel /ses con*ection o (eat ro) deepinterior on*ection is a )/c( aster process o (eat transer t(ancond/ction

In areas de*oid o acti*e tectonics and */lcanicity, t(e (eat o+appears to e in*ersely correlated to t(e ae o t(e roc.s

@ranites prod/ce lare a)o/nts o radioenic (eat, +(ereas asaltsand peridotites prod/ce al)ost no radioenic (eat

@eot(er):ariation o te)perat/re +it( dept(Lateral *ariations in te)perat/res )i(t e d/e to toporap(ic

eects o sea-land o/ndaries (e prole) also arises +(ere t(e lit(osp(ere is stretc(ed o*er arelati*ely narro+ 8one, as is co))on in stri.e-slip asins, so t(att(ere is ot( /p+ard and lateral loss o (eat y cond/ction As is it )o*ed a+ay ro) t(e ride crest, t(e oceanic lit(osp(erecools and contracts (is increases t(e density o t(e oceaniclit(osp(ere and ca/ses a (i(er lit(ostatic stress on t(e /nderlyin)antle

 e)perat/re c(anes ca/se lare c(anes in stress /t relati*elys)all c(anes in density 

@%AI & I#"#A#

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 3/11

 Bo//er ra*ity ano)aly 

CHAPTER 3: Basins due to lithospheric stretching #CMMA%:%its are areas o cr/stal t(innin, de)onstrated y t(e s(allo+dept( o t(e Mo(o, (i( s/race (eat o+s, *olcanic acti*ity,seis)ic acti*ity +it( predo)inantly e4tensional ocal )ec(anis)sol/tions, neati*e Bo//er ra*ity ano)alies and co))onlyele*ated rit )arin toporap(y

At (i(er strain rates, locali8ed rits )ay e*ol*e into passi*e)arins

Passi*e continental )arins are inacti*e, and tectonics aredo)inated y ra*ity-dri*en collapse, (alo.inesis and ro+t(a/ltin !eat o+s near nor)al

2 types: olcanic and non-*olcanic Ineo/s acti*ity is a co))on eat/re o so)e continental rit andpassi*e )arins are t(e point o rea.-/p =*olcanically acti*epassi*e )arins and continental rits stand ele*atedtoporap(ically co)pared to non*olcanic e</i*alents> (ea)o/nt o )elt enerated and its co)position is related to platet(ic.ness, e4cess te)perat/re, stretc( actor and percentae o*olatiles

%its: rittle e4tension o t(e cr/st, ca/sin e4tensional a/ltarrays and a/lt-controlled s/sidence, and t(er)al rela4ationollo+in d/ctile e4tension o t(e lit(osp(ere leadin to reionalpostrit s/sidence

@$"L"@IAL A' @$"P!#IA "B#$%AI"'# I' %$@I"'# "F"'I'$'AL $D$'#I"'

 %its:In areas de*oid o acti*e tectonics and *olcanicity, continental(eat o+ *al/es appear to e stronly correlated +it( t(e type o/nderlyin cr/st %it 8ones c(aracteri8ed y (i( le*els o eart(</a.e acti*ity#eis)ic st/dies s(o+ t(at t(e Mo(o is ele*ated eneat( rit 8ones%it 8ones (a*e c(aracteristic ra*ity sinat/res - typically a lon+a*elent( Bo//er ra*ity lo+, +it( so)eti)es a secondary(i( located in t(e center o t(e rit 8one

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 4/11

%it 8ones are typi;ed y nor)al dip-slip a/lts +it( a *arialen/)er o stri.e-slip a/lts dependin on t(e orientation o t(e rita4is in relation to t(e /l. e4tension direction

PA##I$ "'I'$'AL MA%@I'#

 Passi*e )arins in*ol*e stronly atten/ated continental cr/ststretc(ed o*er a reion o 50-150.), and e4ceptionally as )/c(as E00-500.), o*erlain y t(in or t(ic. sedi)ent pris)s@enerally seis)ically inacti*e and in )at/re e4a)ples (eat o+sare near-nor)al (aracteri8ed y sea+ard t(ic.enin pris)s o)arine sedi)ents o*erlyin a a/lted ase)ent +it( synritsedi)entary se</ences, oten o continental oriin

Arc(etypes o passi*e )arins: olcanically-acti*e )arins: c(aracteri8ed y e4tr/si*e

asalts, lo+er cr/stal ineo/s accretions, and sini;cant/plit at t(e ti)e o rea.-/p ontinental e4tension andocean spreadin are t(o/(t to e inti)ately related to)antle pl/)e acti*ity

'on-*olcanic )arins: lac. e*idence o (i( t(er)al acti*ityat t(e ti)e o rea.-/p Marins )ay e sedi)ent star*ed+it( t(in sedi)ent *eneers or sedi)ent-no/ris(ed +it( *eryt(in. post rit sedi)entary pris)s o*erlyin a s)all n/)ero tilted /pper cr/stal a/lt loc.s and a +ide reion o )id-lo+er cr/stal e4tension

I'%"CI"' " M"$L# "F "'I'$'AL $D$'#I"' Acti*ePassi*e %itin Acti*e %itin: deor)ation is associated +it( t(e i)pine)ent ont(e ase o t(e lit(osp(ere o a t(er)al pl/)e or s(eetond/cti*e (eatin ro) t(e )antle pl/)e, (eat transer ro))a)a eneration on con*ecti*e (eatin )ay ca/se t(elit(osp(ere to t(in I (eat /4es o/t o t(e ast(enosp(ere arelare eno/(, relati*ely rapid t(innin o t(e continental

lit(osp(ere ca/ses isostatic /plit ensional stresses enerated/t /plit )ay t(en pro)ote ritin

Passi*e %itin: tensional stresses in t(e continental lit(osp(ereca/se it to ail, allo+in (ot )antle roc.s to penetrate t(elit(osp(ere r/stal do)in and *olcanic acti*ity are onlysecondary processes %itin ta.es place ;rst, and do)in )ayollo+ /t not precede it %itin is t(ereore a passi*e response toa reional stress ;eld

%eal +orld e4a)ples )ay e4(iit aspects o eac( 

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 5/11

Main )ec(anis) or s/sidence is coolin ollo+in lit(osp(erict(innin: t(e /p+ellin o ast(enosp(ere is ollo+ed y t(er)alcontraction#/sidence )ay also res/lt ro) p(ase c(anes =aro toecloite> in t(e lo+er cr/stal or )antle-lit(osp(ere roc.s

%(eoloy o t(e lit(osp(ere: controlled y te)perat/re and)ineraloy

C'IF"%M #%$!I'@ "F !$ "'I'$'AL LI!"#P!$%$ Mid-ocean ride crests are enerally at ao/t 25 .) +ater dept(,s/estin t(at 8ero-ae oceanic lit(osp(ere /nder 25.) o+ater is in e</iliri/) +it( a standard continental lit(osp(ericcol/)n (ereore, d/rin ritin, t(e ast(enosp(ere s(o/ldt(eoretically not e ale to rea. t(ro/( t(e t(inned continentallit(osp(ere as lon as initial s/sidence is less t(an 25.)"ceanic cr/sts s(o/ld not e o/nd at s(allo+er +ater dept(s

M"IFIAI"'# " !$ C'IF"%M #%$!I'@ M"$L Ass/)ptions:

1 #tretc(in is /nior) +it( dept(2 #tretc(in is instantaneo/s3 #tretc(in is y p/re s(earE (e nec.in dept( is 8ero

5 Airy Isostacy is ass/)ed to operate t(ro/(o/tG (ere is no radioenic (eat prod/ction7 !ear o+ is in one di)ension =*ertically> y cond/ctionH (ere is no )a)atic acti*ity? (e ast(enosp(ere (as a /nior) te)perat/re at t(e ase o

t(e lit(osp(ere 'on-/nior) )odels =dept(-dependent> stretc(in: discontin/o/s andcontin/o/s P/re *s #i)ple #(ear

 #i)ple: t(e lit(osp(ere y e4tend asy))etrically +(ere t(e 8one od/ctile s/ cr/stal stretc(in is relayed laterally ro) t(e 8one orittle cr/stal stretc(in %es/lts in a p(ysical separation o t(e 8one o a/lt-controlled e4tension ro) t(e 8one o /p+elled ast(enosp(ere=3 8ones to t(is s(ear> an e4pect tectonic /plit in t(e reiono*erlyin t(e lo+er cr/st and )antle t(innin

#tretc(in o t(e lit(osp(ere co)ined +it( /nloadin alon )aordetac()ent a/lts can res/lt in t(e /prootin o )antle roc.s in t(eir

ootalls (ese are called core co)ple4es and neissic do)es

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 6/11

Lateral (eat loss d/rin proloned period o ritin is ca/sed y t(elare lateral te)perat/re radients set /p y lit(osp(eric t(innin (eloner t(e ritin e*ent, t(e )ore i)portant lateral (eat loss and /plito a asin )arins are li.ely to e Lateral (eat cond/ction is alsoi)portant in narro+ asins s/c( as p/ll-aparts in stri.e-slip 8ones

$ects o lateral (eat o+ are reatest near t(e asin ede +(ere(ori8ontal te)perat/re radients are larest (e eects decreaseto+ards t(e center o t(e asin

#o)e (a*e ar/ed t(at continental stretc(in is in so)e casesassociated +it( )antle pl/)e acti*ity #/c( acti*ity raises t(e localast(enosp(eric te)perat/res

Lare a)o/nts o stretc(in are li.ely to pro)ote t(e sereation o)elts and t(eir )iration into t(e o*erlyin cr/st (is )eltsereation )odel ass/)es t(at a asaltic )elt sereated ro)ast(enosp(ere t(at (as /p+elled to replace stretc(ed lit(osp(ere (esereated )elt can e considered to eit(er constit/te ne+ oceaniccr/st or to e intr/ded into or to /nderplate t(e stretc(ed lit(osp(ere

'ec.in is t(e *ery lare scale t(innin o t(e lit(osp(ere ca/sed yits )ec(anical e4tension 'ec.in s(o/ld ta.e place aro/nd one o itsstrin layers

$#IMAI"' "F !$ #%$! FA"% A' #%AI' %A$ !I#"% 

Jno+in t(e strain rate (istory or total stretc( actor is i)portant as aasis or predictin t(e eot(er)al radient and (eat o+ (istory oasin sedi)ents, as +ell as in s(o+in t(e role o rit str/ct/res inacco))odatin asin sedi)ents

CHAPTER 4: BASINS DE T! "#E$RE #/))ary:Fle4/re is t(e lon +a*elent( o ;nite strent( ca/sed y t(eapplication o an e4tensional orce syste)Fle4/re o t(e lit(osp(ere is )ost clearly de)onstrated at oceanicislands, sea)o/nt c(ains, ocean trenc(es and oreland asinsLit(osp(eric e4/re also s/pports sedi)ent loads in )ost sedi)entaryasins (e c(aracteristic sinat/re o lit(osp(eric e4/re is aneati*e ree air ra*ity ano)aly =at sea> or a neati*e Bo//erano)aly =on land>

 (e oceanic lit(osp(ere appears to eco)e stroner as it aes andcools, /t it does not +ea.en in its aility to s/pport loads +it( ti)esince loadin

BA#I "B#$%AI"'# I' %$@I"'# "F LI!"#P!$%I FL$DC%$

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 7/11

 Fle4/re o t(e oceanic lit(osp(ere ta.e place at: "ceanic trenc(es, )i-ocean rides, sea)o/nt c(ains and

indi*id/al oceanic *olcanic islandsFle4/re o t(e continental cr/st ta.es place at:

 - sites o ritin, stri.e-slip a/lts, at passi*e )arins and )oste)p(atically at sites o plate con*erence  (e )a4i)/) deection or a ro.en plate o t(e sa)e e4/ralriidity and /nder t(e sa)e *ertical load is trice t(at o an /nro.enplate

 (e continental elastic lit(osp(ere responds dierently to t(e oceaniclit(osp(ere on all scales o deor)ation (e continents appear toacc/)/late strains o*er lon periods o eoloic ti)e +(ereas t(eoceanic lit(osp(ere re)ains relati*ely intact o*er its s(ort lieti)e o/p to ao/t 1H0 Myr

"t(er )ec(anis)s aectin t(e e4/re o t(e continental lit(osp(ereare t(e possile deco/plin o a stron /pper cr/st ro) a stron/nderlyin )antle d/rin plate endin

'AMI# "F "%"@$'I $@$# Foreland asins are dyna)ically lin.ed to associate oroenic elts3 possile )ec(anis)s or t(e dri*in orces responsile or cr/stal

s(ortenin:1: ra*ity slidin2: ra*ity spreadin3: (ori8ontal de*iatoric p/s( 

ritical taper t(eory:Belie t(at t(e oroenic +edes e(a*e as plastic entities as a res/lto t(e inter;nerin o a lare n/)er o t(r/st s(eets into a)ec(anically interdependent syste)

Predicted patters o deor)ation in t(e oroenic +ede res/ltin ro)

e4ternally i)posed c(anes in its eo)etry (e )ost i)portantc(ane res/lts ro) accretion +o types:

1: rontal accretion2: /nderplatin

 

CHAPTER %: E""ECTS !" &ANT#E D'NA&ICS yna)ic toporap(y: t(e toporap(y re)ainin ater t(e re)o*al oisostatic eects ro) t(e oser*ed toporap(y

t(e *ertical displace)ent o t(e $art(6s s/race enerated in

response to o+ in t(e )antle It is t(ereore distinct ro)

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 8/11

isostatic toporap(y enerated y near-s/race density contrastss/c( as cr/stal t(ic.ness c(anes

E(tra notes:on*ection is *ertical =/p-do+n> )otions t(at res/lt ro) t(e densityc(anes t(at occ/r +(en part o a /id is (eated and e4pands

#o it depends on t(e /idKs density, ra*ity =eca/se *ertical )otion>,t(e a)o/nt o e4pansion t(e /id /nderoes, t(e a)o/nt o (eatdierence, t(e t(ic.ness o t(e /id layer, t(e e9ciency y +(ic( t(e/id cond/cts (eat =perect cond/ction +o/ld neate t(e need tocon*ect> and (o+ resistant t(e /id is to o+#trent( is a )eas/re o a )aterialKs aility to +it(stand an appliedstress +it(o/t rea.in =r/pt/rin> in so)e +ay

 (e res/lts o t(e /p+ellin o t(e ast(enosp(ere are (i( (eat o+,neati*e Bo//er ano)alies, and oten s/race *olcanis)

Floatin:Isostasy is all ao/t oatin@ra*itational stress =t(e +ei(t> o a oatin oect ca/sesdisplace)ent o t(e /id, so parts o t(e oect s/)ere (e s/)ered parts e4perience /oyancy eca/se o t(e press/redierence et+een t(eir tops and otto)sFloatin (appens +(en t(ese t+o orces are e</ally alanced

"roenic +ede e*ol/tion can e )odelled /sin ritical aper (eoryritical aper (eory descries t(e alance o orces +it(in a +ede oroc.s ein t(r/st alon an inclines detac()entPratt isostasy : !eatin y a (ot pl/)e in t(e ast(enosp(ere decreasedt(e lit(osp(eric density and estalis(ed lon +a*elent( toporap(yat t(e s/race (is toporap(y is static, as t(e isostatic calc/lationdescries stale oatin B/t t(e (ot pl/)e is not static Its *iscosity)eans t(e /oyancy-related stresses t(at dri*e its rise can etrans)itted into t(e lit(osp(ere ao*e it (is )eans an additionalp/s( at t(e ase o t(e lit(osp(ere, litin it /p (i(er still (is iscalled dyna)ic toporap(y

ontinental collision is /nli.e s/d/ction in t(at t(econ*erent plates (a*e to do +or. aainst ra*ity, rat(er t(an einassisted y it =sla allin>

 (e continental lit(osp(ere is also )ore (eteroeneo/s, ot(laterally and *ertically, introd/cin additional constraints on t(eo/ndary style

As a res/lt, continental collision styles *ary )assi*ely, andconictin ideas ao/t eodyna)ic processes can e inerred ro)t(e)

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 9/11

 se)ul De*nitions: Euler Poles: $/ler poles descrie instantaneo/s rates o rotation oone plate or continental ra)ent +it( respect to anot(er

Ridge Push "orce: or slidin plate orce is a proposed )ec(anis) orplate )otion in plate tectonics Beca/se )id-ocean rides lie at a(i(er ele*ation t(an t(e rest o t(e ocean oor, ra*ity ca/ses t(eride to p/s( on t(e lit(osp(ere t(at lies art(er ro) t(e ride Ra+leigh nu,-er: or a /id is a di)ensionless n/)er associated+it( /oyancy dri*en o+ =also .no+n as ree con*ection or nat/ralcon*ection> (en t(e %aylei( n/)er is elo+ t(e critical *al/e ort(at /id, (eat transer is pri)arily in t(e or) o cond/ction +(en ite4ceeds t(e critical *al/e, (eat transer is pri)arily in t(e or)o con*ection Serpentini.ation: #erpentini8ation is a eoloical lo+-te)perat/re)eta)orp(ic process in*ol*in (eat and +ater in +(ic( lo+-silica )a;c and /ltra)a;c roc.s are o4idi8ed =anaeroic o4idation o Fe2N yt(e protons o +ater leadin to t(e or)ation o !2> and (ydroly8ed +it( +ater into serpentinite (e density c(anes ro) 33 to 27c)3 +it( a conc/rrent *ol/)e increase on t(e order o 30-E0O (ereaction is (i(ly e4ot(er)ic and roc. te)perat/res can e raised yao/t 2G0 =500 F>,Q1R pro*idin an enery so/rce or or)ation o

non-*olcanic (ydrot(er)al *ents

 'oung/s &odel:also .no+n as t(e tensile ,odulus or elastic ,odulus, is a)eas/re o t(e stiness o an elastic )aterial and is a </antity /sed toc(aracteri8e )aterials It is de;ned as t(e ratio o t(e stress alonan a4is o*er t(e strain alon t(at a4is in t(e rane o stress in+(ic( !oo.e6s la+ (olds Plastic de)or,ation: (is type o deor)ation is irre*ersile !o+e*er, an oect in t(e

plastic deor)ation rane +ill ;rst (a*e /nderone elasticdeor)ation, +(ic( is re*ersile, so t(e oect +ill ret/rn part +ay toits oriinal s(ape #ot t(er)oplastics (a*e a rat(er lare plasticdeor)ation rane as do d/ctile )etals s/c( as copper, sil*er,and old #teel does, too, /t not cast iron !ard t(er)osettinplastics, r/er, crystals, and cera)ics (a*e )ini)al plasticdeor)ation ranes "ne )aterial +it( a lare plastic deor)ationrane is +et c(e+in /), +(ic( can e stretc(ed do8ens o ti)es itsoriinal lent(Cnder tensile stress plastic deor)ation is c(aracteri8ed y a strain

(ardenin reion and a nec.in reion and ;nally, ract/re =also calledr/pt/re> /rin strain (ardenin t(e )aterial eco)es stroner

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 10/11

t(ro/( t(e )o*e)ent o ato)ic dislocations (e nec.in p(ase isindicated y a red/ction in cross-sectional area o t(e speci)en'ec.in eins ater t(e /lti)ate strent( is reac(ed /rin nec.in,t(e )aterial can no loner +it(stand t(e )a4i)/) stress and t(estrain in t(e speci)en rapidly increases Plastic deor)ation ends +it(

t(e ract/re o t(e )aterial De0iatoric 1tectonic2 stresses:In eoloy t(e de*iatoric stress is a )eas/re o t(e stress actin todeor) a roc. #tress is t(e orce per /nit area on a s/race +it(in a)aterial I t(e stress in e*ery direction is e</al t(e stress is(ydrostatic and t(e stress in any direction is e</al to t(e )ean stressA de*iatoric stress is not e</al in e*ery direction and represents ade*iation ro) t(e )ean (e larest de*iation ro) t(e )ean is t(eprinciple stress and (as ot( direction and )anit/de Fold a4es andoliations in reional )eta)orp(ic roc.s are oriented roadlyperpendic/lar to t(e principle stress direction e*iatoric stress (as a partic/larly i)portant application in t(ederi*ation o stress orientation and )anit/de ro) a/lt slip data 

Bouguer Ano,al+: is a ra*ity ano)aly, corrected or t(e (ei(t at+(ic( it is )eas/red and t(e attraction o terrain (e (ei(tcorrection alone i*es a ree-air ra*ity ano)aly 

"ree air ano,al+: is t(e )eas/red ra*ity ano)aly ater a )reeaircorrection is applied to correct or t(e ele*ation at +(ic( a)eas/re)ent is )ade (e ree-air correction does so y ad/stint(ese )eas/re)ents o ra*ity to +(at +o/ld (a*e een )eas/red atsea le*el Bacstripping:  is a eop(ysical analysis tec(ni</e /sedon sedi)entary roc. se</ences - t(e tec(ni</e is /sed to</antitati*ely esti)ate t(e dept( t(at t(e ase)ent +o/ld e in t(easence o sedi)ent and +ater loadin (is dept( pro*ides a)eas/re o t(e /n.no+n tectonic dri*in orces t(at are responsile

or asin or)ation =ot(er+ise .no+ as tectonic s/sidence or /plit>By co)parin ac.stripped c/r*es to t(eoretical c/r*es or asins/sidence and /plit it is possile to ded/ce inor)ation on t(e asinor)in )ec(anis)s Air+ Isostac+: calc/lated y ass/)in t(e press/re at t(e top o t(e/id ast(enosp(ere is t(e sa)e eneat( t(e (i(land as it is eneat(t(e lo+landPratt Isostac+: Lateral density *ariations can )a.e toporap(y too=Pratt isostasy) (e toporap(y (ere is t(e sa)e as eore /t its

ca/se is a red/ction in lit(osp(eric )antle density res/ltin ro)(eatin y a pl/)e in t(e ast(enosp(ere

7/24/2019 Basin Analysis Notes

http://slidepdf.com/reader/full/basin-analysis-notes 11/11

 Intraplate strain:eco)paction: