第八節(jié)垂直構(gòu)造

底辟構(gòu)造

Diapirsstructure

地下較深處的密度相對(duì)小的高塑性巖層或巖體在差異重力等機(jī)制作用下向上拱起或刺穿上覆巖層形成的一種構(gòu)造。是垂直構(gòu)造類型的一種。

一、底辟構(gòu)造結(jié)構(gòu)要素及基本特征：

（1）.底辟核

（2）.核上構(gòu)造

（3）.核下構(gòu)造

第八節(jié)垂直構(gòu)造

底辟構(gòu)造

Diapirsstruc1－底辟核；2－核上構(gòu)造；3－核下構(gòu)造1.底辟構(gòu)造的結(jié)構(gòu)要素1－底辟核；2－核上構(gòu)造；3－核下構(gòu)造1.底辟構(gòu)造的結(jié)構(gòu)要小型底劈構(gòu)造小型底劈構(gòu)造小型底劈構(gòu)造小型底劈構(gòu)造盆地中的底劈構(gòu)造？？盆地中的底劈構(gòu)造？？泥底劈鹽底劈（硫酸鹽、碳酸鹽、石鹽）巖漿底劈2.底劈構(gòu)造核部巖性類型泥底劈鹽底劈（硫酸鹽、碳酸鹽、石鹽）巖漿底劈2.底劈構(gòu)造核部鹽底劈鹽底劈TopTagluStructuremapshowingtherelationshipbetweenthepresent-daycompressional泥底劈ReleasingBend釋放彎曲ReatrainningBend約束彎曲TopTagluStructuremapshowin3.底劈構(gòu)造核上部的正斷層常呈環(huán)狀或放射狀3.底劈構(gòu)造核上部的正斷層常呈環(huán)狀或放射狀樂(lè)東氣田——樂(lè)東l5-1構(gòu)造是鶯歌海盆地諸多泥底辟構(gòu)造之一樂(lè)東氣田——樂(lè)東l5-1構(gòu)造是鶯歌海盆地諸多泥底辟構(gòu)造之一油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure放射狀平形狀放射狀平形狀鹽構(gòu)造可以由以下6種機(jī)制觸發(fā)引起：①浮力作用;②差異負(fù)載作用;③重力擴(kuò)張作用;④熱對(duì)流作用;⑤擠壓作用;⑥伸展作用。核部由鹽類組成的底劈構(gòu)造稱為鹽丘。4.鹽丘的形成機(jī)制鹽構(gòu)造可以由以下6種機(jī)制觸發(fā)引起：核部由鹽類組成的底劈構(gòu)造稱撒哈拉穹窿——理查德構(gòu)造撒哈拉穹窿——理查德構(gòu)造油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure理查德構(gòu)造——相當(dāng)于非洲之眼的眼球理查德構(gòu)造——相當(dāng)于非洲之眼的眼球非洲之眼是晚白堊紀(jì)堿性巖漿熱液上侵，沿灰質(zhì)白云巖陸架的環(huán)狀同生斷裂上侵，引發(fā)地表穹隆侵蝕和熱液卡斯特作用，由此而形成一個(gè)直徑40公里的眼珠狀構(gòu)造。巖漿上侵穹窿？非洲之眼是晚白堊紀(jì)堿性巖漿熱液上侵，沿灰質(zhì)白云巖陸架的環(huán)狀同含巖鹽盆地的鹽丘是是最常見(jiàn)的一類底劈構(gòu)造，與油氣關(guān)系密切。世界含鹽盆地分布含巖鹽盆地的鹽丘是是最常見(jiàn)的一類底劈構(gòu)造，與油氣關(guān)系密切。世鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)構(gòu)造位置與鹽構(gòu)造類型構(gòu)造位置與鹽構(gòu)造類型Asillustratedonthisseismicline,itisquiteobviousthesaltandoverburdenhavebeenshortened(compressionstillisgoingon)byacompressionaltectonicregimethatsomeassociatewithridgepushingforces.Thefaultsinthetopoftheantiformsarestrike-slipandnotnormalfaults.Timeslicesbetween3.0and3.2seconds,stronglysuggestthatsuchafaultselongatetheanticlineaxisalongthes2

二、鹽底劈構(gòu)造類型及特征鹽背斜1.擠壓鹽構(gòu)造AsillustratedonthisseismicFig.25-Thesaltweldinthecentralpartofthelinesuggeststhatbeforedeformationthesaltlayerwascontinuousbetweentheyellowandbrowninterval.Then,theinfra-saltstratawerelengthenedbynormal-faultscreatingpotentialvoidsthatwerefilledbysalt(“saltgrabens”)duetoalateralsaltflowage,whichcreatedawindowinthesaltlayer.Finally,acompressionaltectonicregimeshortenedthecoverinvertingthesaltgrabens.Fig.25-ThesaltweldintheItisinterestingtonoticethatindepth,thedistalthrustfaultcorrespondstotheseawardlimitofasaltbasin.Seaward,thesaltisallochthonousandformsasaltnappe,whichhasbeenreactivatedandshortenedprobablybyridgepushforces.Itisquiteobviousthatthethicknessofthesaltisapparentandduetothrusting.Somearguedthatthesaltbeingthickerintheultradeepoffshorewastheproofofanuniquepristinesaltbasinthatwaslatersplitintwo.Recently,suchaerroneouslyhypothesishasbeensystematicallyfalsified.推覆體

外來(lái)鹽ItisinterestingtonoticethTheregionalgeologicalsettingofthislinestronglysuggeststhesesaltstructureswerecreatedbyacompressionaltectonicregime.Themappingofthefaultsonthetopoftheoverburdenstructuresshowsthattheyaresmallstrike-slipfaultswhichelongatetheaxisoftheanticlinealongthe2.

TheregionalgeologicalsettinRidgepushforcesseemtoberesponsibleoftheshorteningofthecoverindeepwater,wheresaltdiapirshavebeensqueezedandbackthrusted,aswellasthe

mini-basinsbetweenthem.Thegeometricalrelationshipsbetweentheseismicreflectors(seismicsurfaces)andthemorphologyoftheseafloorstronglysuggestthatshorteningstillisgoingon.擠入底劈Ridgepushforcesseemtober該測(cè)線上，有微型盆地在外來(lái)巖層上，只能用原生鹽抽真空作用來(lái)解釋。在測(cè)線的中部，沿著陡沖斷層，鹽向上移動(dòng)。右下角可見(jiàn)鹽下地層和裂縫型盆地）鹽排出盆地該測(cè)線上，有微型盆地在外來(lái)巖層上，只能用原生鹽抽真空作用來(lái)解ThisinterpretationtakesintoaccounttheRayleigh-Taylorinstability.Duringlongtime,inthisarea,erroneouslylargediapiricstructures(>30kmwide)wereproposed.Withsuchlargesaltstructuresexplorationistsgiveuptheareaduetoabsenceofsignificanttraps(indepth,suchstructureswere3-4timesthickerthanthebasinitself).Itisobviousthatinterpretationswithsaltcanopystructuresstronglychangethepetroleumpotential,atleastthetrappingparameter.鹽蓋

SaltWeld-鹽連接；鹽頸ThisinterpretationtakesintoThe

primarysaltweldrecognizedinthecentralpartofthethelineemphasizesthetectonicdisharmonyassociatedwiththebottomofthesaltlayer.Theoverburdenandsub-saltstratashowquitedifferentdeformations.Saltrollerarerecognizedonthebottomofpre-raftstructures.

(原生的鹽焊接被公認(rèn)為在線的中部，強(qiáng)調(diào)構(gòu)造不整合與鹽層底部有關(guān)。蓋層和鹽下地層表現(xiàn)出不同的突變，巖鹽隆起被認(rèn)為在預(yù)流體結(jié)構(gòu)的底部）鹽滑脫

TheprimarysaltweldrecognizFig.12-Thisseismicline,fromtheNeuquenbasin(onshoreArgentine),illustratesacompressivestrike-slipshorteningoftheforedeepsediments,inwhichaCretaceousevaporiticlayer(Hutrimformation)wasdeformedinconcordancewithallotherintervals.Similarly,butnosoevident,anOxfordiansaltlayer(Auquilcoformation)wasinverted(invertedrift-typebasininlowermiddlepartoftheline)withdevelopmentof

“enechelonfolds”intheup-thrownfaultedblock.Notice,thattwodifferentcompressionaltectonicregimes,onewiththebasementinvolvedandayoungerwithoutinvolvementofthebasementcanalsoexplainedthedeformationrecognizedonthisline.壓扭性鹽構(gòu)造Fig.12-Thisseismicline,frFig.13-Compressivestrike-slipstructures(faultedconical-folds)inducedbyreactivationoffracturezonesarefrequentinSouthAtlanticmargins.Loemesalt(KwanzaandSouthCongobasins)formsoftenthecoreofanticlinestructures.Similarly,theOligoceneunconformityisupliftedandlocallyerodedbeforebeingfossilisedbyTertiarydeepwaterdeposits.壓扭性鹽構(gòu)造Fig.13-Compressivestrike-slInspiteofthestretchedhorizontalscale,thesaltflats,atthebottomoftheallochthonoussaltsheet,arequitewellrecognizedonthisline.

斷坪

外來(lái)鹽2.伸展鹽構(gòu)造InspiteofthestretchedhoriStretchingfaultsstrikeinalldirections.Theyareinducedbylocalextensiontectonicregimes,inwhich2and

3areequal.Astheyelongatethesedimentstoaccommodatethemtonewvolumeconditions,Onseismiclinestheyhaveoppositevergences.Theoretically,thesumofthrowswithoppositevergencemustbezero.伸展斷層StretchingfaultsstrikeinalOnthisseismicline,adeep

primarysaltweld(around6seconds)underlinestheevacuationofautochthonoussalt.Intheupperstratigraphiclevels,allochthonoussaltisquiteobvious.Takingintoaccountthedimensionsofthecentralsaltbodyaswellasthegeometryoftheupperandlowercontacts,itcanbeconsideredasasaltlaccolith.鹽蓋

Onthisseismicline,adeeppSeismicexpressionoftheSigsbeeEscarpment.Themaindrivingmechanismofsuchbathymetricfeaturesiswellillustratedonthisprofile.SeismicexpressionoftheSigsInoffshoreBrazil,fromwherethislinecomes,thesourcesaltlayer,i.e.,autochthonoussaltoverliesthepotentialsourcerocks.ContrariwisetoWestAfricansaltbasins,wherethemajormarinesourcerocksisintheoverburden,here,thepotentialmarinesourcerocksneverreachedmaturation.Indeed,asillustrated,theoverburdenisrelativelythin.Itsmaximumthicknessisaround3seconds.

InoffshoreBrazil,fromwhereSalttonguesastheoneillustratedonthisseismiclinearequitedifficulttodistinguishofsaltlaccoliths

orsaltsheets

鹽舌

鹽斜坡SalttonguesastheoneillustAsillustratedonthisseismicline,thelateralflowage

ofthesaltisthemainresponsibleforthecreationofspaceavailableforthesediments,thatistosay,itinducesacompensatorysubsidence.Indeed,inthelowerintervalsoftheoverburden,thethicknessvariations(thinabovethebulgeandthickabovethesaltsynforms)canonlybeexplainbysaltflowage,inspiteofthefact,thatthegeometryoftheupperintervalsoftheoverburdensuggestsalateshortening.側(cè)向流動(dòng)

AsillustratedonthisseismicSaltrollersarecharacteristicofpre-raftdomain,whichgenerallyareassumedtobelocatedinupperslopeorplatform.ThislinecomesfromthedeepwaterofAngola,wheresaltrollersarequiteobvious.Suchanoccurrencehasimportantimplicationsfortheoriginofthehighqualitycalcareousreservoirs.鹽隆起SaltrollersarecharacteristiThissaltsheetstillisconnectedwiththe

mothersourcelayer,whichispartiallyrepresentbyprimarysaltwelds.Thefeederortheramp,whichlaterwillbecomeacounter-regionalfault,iswellrecognized.Noticenthetopofthesaltsheet

several

Rohofaults.鹽片

ThissaltsheetstillisconneAtthebottomofthissaltsill(i)basalcutoffs,(ii)saltflatand(iii)saltrampsareeasilyrecognized.However,thesesaltrampsshouldnotbeconfusedwiththesaltrampssynonymoffeeders.鹽床AtthebottomofthissaltsilThesynkinematiclayers,asthoseillustratedabove,thickeningtowardthegrowth-faults.Theyrecordsedimentationduringsaltfloworduringanyothertypeofdeformation.Thelightgreenandblueintervalsareprekinematic,whichareroughlyisopach.同運(yùn)動(dòng)層Thesynkinematiclayers,asthFig.24-Thelengtheningofthesedimentsisevident.Thetectonicregimeischaracterizedby1vertical.Theantiformmorphologyoftheseabottomisquitesignificant.Themajorityofthenormal-faultsdieonthetectonicdisharmonyassociatedwiththesaltlayer(topofthesalt)

Fig.24-ThelengtheningofthFig.26-SaltridgesandgrowthfaultsarefrequentinSantosbasin(offshoreBrazil).Takingintoaccountthatthedeformationoftheinfra-saltstrataisapparentandduetovelocity-inducedlateralpull-ups,onecansaythatbelowthetectonicdisharmonythesedimentsarealmostundeformed.Aboveit,saltridgesandgrowthfaultsextendedtheoverburden.Fig.26-SaltridgesandgrowtFig.27-IndeepwaterAngola,CretaceoussedimentsandparticularlythePindaformation,whichisapotentialreservoirintervalintheoffshoreshelf,wereextendedbygrowth-faultsdevelopedonthetopofthesaltlayerduetoanextensionaltectonicregimecharacterizedby1vertical,2horizontalstrikingmoreorlesN-Sand3horizontalandW-E.Fig.27-IndeepwaterAngola,Thesaltpillowiscompletelydisconnectedofthemothersourcelayer.Itislimitedbytwo

primarysaltwelds.Thisantiformsaltstructure,recognizedin1968,onSeffellines,became,recently,wellknownofallexplorationistsworkinginWestAfricaoffshores.Indeed,majoroilfieldshavebeenfoundaroundthetopoftheantiform.Noticetheslightpull-upofthetectonicdisharmonyinducedbythesaltpillow.鹽枕

3.差異壓實(shí)鹽構(gòu)造ThesaltpillowiscompletelyFig.18-InNordkapbasin(BarentsSea),thebasementisnotinvolvedindeformation(atleastintheareawherethislinewasshot).Inabsenceofsignificanttectonicstress,thethickPermiansaltlayerflowedupwardformingquitelargesaltdiapirs,whichdeformedtheoverburden.Notethattheflanksofthediapiricstructuresarenotvertical(physicalimpossibility)andtheoverburdenismainlyprekinematic(regionally,theoverburdenshowsanorthwardthickening).Fig.18-InNordkapbasin(BareFig.20-Halokinesisisnotasimpleupwardflowageofthesubstratum.Indeed,averticalsediment/saltinterfaceisphysicalinstability.Asillustrated,onthisseismicline,aboveagivenpoint(inversionpoint),thedensityofthesaltishigherthanthedensityofthejuxtaposedsediments(seelater).Therefore,abovetheinversionpoint,saltflowslaterally.Indeed,thesedimentconfiningpressureisnotbigenoughtobalancetheconfiningpressureinducedbysalt.鹽構(gòu)造作用Fig.20-HalokinesisisnotaOnthisline,thesaltweldisquiteobvious.The

saltmotherlayerisrecognizedinbothsidesofthe

saltweld.Thedepocenterlocatedabovethesaltweldcanonlybeexplainedbycompensatorysubsidence,thatistosay,bywithdrawalofthesalt.Onthisline,thesaltweldisSaltweltsarenotsynonymofsaltanticlines.Theyareextensionalsaltstructures,generally,createdbysaltflowage.Sometimestheycorrespondtosaltupwellings,asillustratedonthisline.Theinternalconfigurationofthelowermostintervaloftheoverburdenisdivergenttowardthesynforms,whatsuggeststhatitisasynkinematiclayer.Thesaltstartedtoflowatquiteshallowdepth.SaltweltsarenotsynonymofThegeometricalrelationshipsbetweentheoverburdenreflectorsandthetopofthesalt,aswellasthethicknesschangesaremainlyinducedbysaltwithdrawal,whatcreatesasignificantdifferentialcompensatorysubsidence.Thegeometry,andtheinternalconfiguration,ofthelightgreenseismicinterval(outcroppingjustabovethesaltstructure)indicatesthatthesaltdiapirwasreactivatednotlongtimeago.ThegeometricalrelationshipsSecondaryperipheralsinksareoftenassociatedwithtectonicinversionswhetherduetoareactivationofthediapirorlateregionalcompression.SecondaryperipheralsinksareOnthisseismicline,theoverburdenisquitedeformed,whilethesub-saltstrataismainlyundeformed.Theundulationsofthesub-saltstrataareapparent.Theyareinducedbylateralchangesinthevelocityoftheoverburden.Indeed,attheverticalofeachsaltdome,thesub-saltstrataarepulled-up.Themajorityofthesaltdomesisdisconnectedofthe

mothersourcelayer.Infact,theyareseparatedby

primarysaltwelds

鹽帽O(jiān)nthisseismicline,theoverAsillustratedabove,onecansaysaltplugsarecomposedbyastemandabulb.Onthisline,thesaltstockisdisconnectedfromthemothersourcelayer.Twoprimarysaltweldsseparatethesaltstockfromthemothersaltlayer.鹽株Asillustratedabove,onecanOnthisseismicline,thestemisrelativelynarrow,incircumference,inproportiontotheheightofthediapir,whichseemscompletelydisconnectedofthemothersourcelayer.Indeed,twoprimarysaltweldscanberecognizedaroundthediapir.莖Onthisseismicline,thestemSaltstocksareformedbyastemandabulb.Theycanbeconnectedordisconnectedofthe

mothersourcelayer.鹽干球莖柱莖SaltstocksareformedbyastThelateralsaltflowageorsaltreduction,i.e,theevacuationofthesaltcreateda

primarysaltweldandalocaldepocentersintheoverburden.Thesaltreductionstronglyincreasedthespaceavailableforthesediments(accommodation),whichgeneratedthreelocalbutanobviousdepocentersinthesynkinematicintervalsoftheoverburden.Thelightblueintervalseemsprekinematic.

鹽消減

ThelateralsaltflowageorsaThesuturesbetweenthedifferentsaltstockstoformasalt-stockcanopystillareeasyrecognizedonthistimeslice,whichdepthislessthan0.5secondbelowseafloor.鹽株頂蓋

ThesuturesbetweenthedifferAllochthonoussaltsheetsorsaltstockscangatheredtoformlarge

saltnapesorsalt-stockcanopies.Here,itisobviousthatsalt-stocksarecoalescingtoformasalt-stockcanopy.

鹽接合線

AllochthonoussaltsheetsorsSecondarysaltweldshaveoftenaverticalgeometry,orundatedwhenlateregionalcompressionstakeplace.Aprimaryandatertiarysaltweldsarealsoeasilyrecognized.再生的鹽連接4.復(fù)雜成因鹽構(gòu)造SecondarysaltweldshaveofteFig.16-IntheCaspianSea,nearbythehugeKasaghanoildiscovery(darkblue),saltridgesstrikeperpendicularlytothethrust-faultsandcylindrical-foldsofthefold-belt(intheleftendoftheline).Therefore,isquitepossiblethantheywerecreatedbythelesseningtectonicregime(seetablesIandII).張扭性鹽構(gòu)造Fig.16-IntheCaspianSea,nFig.19-Thisantiformstructureisatypicalextensionalstructurecreatedbyhalokinesis.Thelateraldepocentersisasynkinematicintervalsdepositedinassociationwithacompensatorysubsidencecreatedbysaltflowage.Thecoreofthestructure,whichismainlyprekinematic,wasinvertedbyhalokinesis.Thenormal-faults(withoppositevergence)neartheapexofthestructurestronglyextendtheoverburden.鹽構(gòu)造作用Fig.19-ThisantiformstructuTectonicinversions,astheoneillustratedonthisseismicline,implylengtheningoftheuppersedimentarylayers.Therefore,normalfaultingisalwaysassociatedwith.Thepresenceorabsenceofnormalfaults,neartheapexofdomalstructures,canbeusedtodifferentiateinversionsfromanticlines.構(gòu)造反轉(zhuǎn)Tectonicinversions,astheonInoffshoreAngola,aswellasinonshore,thesaltsourcelayeristheAptiansaltwhich,stratigraphicallyspeaking,itwasdepositedabovetheCretaceousbasalsandstones(yellow,CuvoandChelaformation)ofthedivergentmarginandbelowtheAlbianlimestones(green,BingaandPindaformations).InAngola-GabonandBrazil,thesourcelayersaredifferent.Indeed,andcontrariwisetoanerroneoushypothesis,stillfollowedbysomegeologists,theseAptiansaltbasinswerealwaysindividualizedbysubaerialandoceanicspreadingcenter.InoffshoreAngola,aswellasOnthisseismic,wherethe

autochthonousandallochthonoussaltlayersareeasilyrecognize,secondorderdiapirsareindividualized.Onthisseismic,wheretheautShearzonesandparticularlyfaultzonesareoftenfeedersofsaltextrusionasillustratedonthisseismicline.Actually,onthisarea,someofthesefault,smoreorlessinjectedbysalt,areseismicallyactivesandhavebeenthesourceofmajorearthquakes.ShearzonesandparticularlyfIntheGulfCoast,asillustratedabove,themajorityoftheallochthonoussaltstructurehavebeeninflatedmainlyduetodifferentialloading.

席狀或舌狀增厚IntheGulfCoast,asillustraFig.21-Halokinesiscancreatecomplexstructuresparticularlywhenthereissuperimpositionofautochthonousandallochthonoussaltstructures,asisthecaseonthisseismiclinefromGardenBanks(deep-waterGulfofMexico),where,atleasttwosalt-inducedtectonicdisharmoniesordécollementsurfacescanpredicted.鹽構(gòu)造作用外來(lái)鹽Fig.21-HalokinesiscancreatOnthisline,itisquiteevidentthattheallochthonoussalt

structurewascreatedbysaltinjectionunderrelativethinsedimentarycover(thinnerthanpresently).鹽床注入Onthisline,itisquiteevidAsillustratedonthisseismicline,theoriginalsaltsheet

issplittingupbyaprogressivewestwarddevelopmentofsaltexpulsionbasins.Thecounter-regionalfaults,inthecentralpartoftheline,istheramp

orthefeederofthe

saltsheet.席狀分裂AsillustratedonthisseismicThedepocenterabovethesaltdomecanbeexplainedasaconsequenceofasaltcollapsefollowingthesubsurfaceerosionduetosaltdissolution.潛蝕作用ThedepocenterabovethesaltOnthisseismicline,

sub-saltstrataiscomposedbythebasalCretaceoussandstoneofthemargin(inyellow)andrift-typebasinsediments(inbrown).Theinfrastructureofthesub-saltstrataisthePrecambrian

basement.Onthisseismicline,sub-saltGenerally,inacontinentaldivergentmargin,thesubstratumisformedbyinfra-saltmarginsediments,whichoverlyeitherarift-typebasinsediments,aPaleozoicfoldbeltoraPrecambrianbasement.Onthisparticularexample,inwhichtheinfra-saltmarginsedimentsareunderseismicresolution,thesubstratumofthesaltisaPrecambrianbasement.底部層Generally,inacontinentaldiSalt-tonguecanopiesarequitedifficulttorecognizeonseismiclines.However,theycaneasilytoberecognizedonshallowtimeslicesknowingtheabovegeologicalmodel.Indeed,seismicinterpreterscanonlyrecognizeonseismicdatawhattheyknown,i.e.,inseismicinterpretationTheoryprecedesObservation.三、鹽構(gòu)造空間特征舌狀鹽蓋縫合線葉狀生長(zhǎng)邊緣發(fā)育程度增加Salt-tonguecanopiesarequiteAsillustratedabove,withtime,saltwallscancoalescedandformquitelargesaltwallcanopies.Often,timeslicesallowtorecognizethesuturesbetweenthedifferentsaltwallsorthesuturesynforms,whichalloweasilydifferentiatesaltwallcanopiesfromsaltnapes.墻狀鹽蓋縫合線縫合向斜縫合交接背斜發(fā)育程度增加Asillustratedabove,withtimSaltwallsareeasilyrecognisedontimeslicesorongeologicalmaps.Onthismap,thesaltstructures(inblack)aremainlyelongated,particularlyonthesouthernpart,andparalleltotheshoreline。SaltwallsareeasilyrecognisFig.15-Thissketchillustratestheconjecturethatthetectonicstressdecreaseprogressivelyindirectionofthecraton,thatistosay,awayfromtheorogenicbelt.Indeed,thetectonicstressismoreorlessconstantwithintheconsideredlithosphericplate.However,asthestrengthtodeformationoftherockschange,deformationoccurswherethesedimentscannotstandanymoretheeffectivestresses.Insuchatectonicsetting,when1

isvertical,saltlayers,iftheyweredepositedwillbedeformedinsaltridgesstrikingperpendicularlytothecylindrical-foldsandthrustsofthefold-belt.前陸造山帶理想化的變形情況四、區(qū)域鹽構(gòu)造特征Fig.15-ThissketchillustratSomegeologistsusedtheSaltTectonicswhenanextensionaltectonicregime

isactive,and

Halokinesiswhensaltdeformationtakeplaceinabsenceofasignificanttectonicstress.However,asillustratedonthisregionalgeologicalcross-section,ataregionalscale,i.e,atthescaleofabasin,extensionalandcompressionaltectonicregimes

arealwayspresent.Locally,almostallsaltstructurescanbeexplainjustbyhalokinesis.However,atthescaleofthebasin,halokinesisplaysasecondaryifnotameaninglessrole.區(qū)域鹽構(gòu)造特征SomegeologistsusedtheSalt五、沉積盆地構(gòu)造體制應(yīng)力狀態(tài)基底卷入型蓋層滑脫型區(qū)域有效應(yīng)力缺失下部流動(dòng)層巖鹽流動(dòng)層泥巖流動(dòng)層擠壓脫頂構(gòu)造減薄平衡牽引構(gòu)造不協(xié)調(diào)裂谷-伸展走滑五、沉積盆地構(gòu)造體制應(yīng)力狀態(tài)基底卷入型蓋層滑脫型區(qū)域有效應(yīng)力沉積盆地鹽構(gòu)造與應(yīng)力狀態(tài)沉積盆地鹽構(gòu)造與應(yīng)力狀態(tài)油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structureFig.14-Whenanevaporiticintervalispresentinastratigraphiccolumnundergoneatectonicregimewith1verticalcreatedbyat>0,itisdeformedintomoreorlessparallelsaltridges.Indeed,saltridgesareextensionalstructures(antiforms),whichoftenformthecoreofregionalextensionaldepressions(grabens)strikingperpendiculartotheaxesofthefoldsandreverse-faultsofthefoldedbelt.Therefore,saltdeformationandnormalfaultingarecoeval.Fig.14-WhenanevaporiticinFig.17-Asillustratedintheblockdiagram,thefaultingassociatedwiththistectonicregimeischaracterizedbynormal-faultsstrikinginalldirections(2=Thisfaultpatternisalsooftenrecognizedonantiformstructurescreatedbydifferentialcompaction.When,athickmobilelayer(saltorunder-compactedshale)ispresent,eveninabsenceofasignificanttectonicstress,itcanflowbyitself.Halokinesisdesignatesthesaltandoverburdendeformationstakingplaceinsuchatectonicsetting(absenceofatectonicstress),whileargilokinesisdenotesthedeformationsassociatedwithanunder-compactedshaleinterval.限制應(yīng)力上覆地層壓力Fig.17-AsillustratedintheFig.22-Saltridgesareparallelto2,whichgenerallyismoreorlessparalleltotheshorelineofthedivergentmarginswherethistectonicregimeiscommon(fig.24).Fig.22-SaltridgesareparalFig.23-Growthfaultsareoftencreatedbylateralsaltflowage.Residualsaltcanisfrequentlyrecognisedintheup-thrownfaultedblockundertheformofsaltrollers.Fig.23-Growthfaultsareoft三種伸展應(yīng)力狀態(tài)下的鹽脊形態(tài)三種伸展應(yīng)力狀態(tài)下的鹽脊形態(tài)1.構(gòu)造應(yīng)力小于01.構(gòu)造應(yīng)力小于02.構(gòu)造應(yīng)力等于0（重力作用下）2.構(gòu)造應(yīng)力等于0（重力作用下）3.構(gòu)造應(yīng)力大于03.構(gòu)造應(yīng)力大于0第八節(jié)垂直構(gòu)造

底辟構(gòu)造

Diapirsstructure

地下較深處的密度相對(duì)小的高塑性巖層或巖體在差異重力等機(jī)制作用下向上拱起或刺穿上覆巖層形成的一種構(gòu)造。是垂直構(gòu)造類型的一種。

一、底辟構(gòu)造結(jié)構(gòu)要素及基本特征：

（1）.底辟核

（2）.核上構(gòu)造

（3）.核下構(gòu)造

第八節(jié)垂直構(gòu)造

底辟構(gòu)造

Diapirsstruc1－底辟核；2－核上構(gòu)造；3－核下構(gòu)造1.底辟構(gòu)造的結(jié)構(gòu)要素1－底辟核；2－核上構(gòu)造；3－核下構(gòu)造1.底辟構(gòu)造的結(jié)構(gòu)要小型底劈構(gòu)造小型底劈構(gòu)造小型底劈構(gòu)造小型底劈構(gòu)造盆地中的底劈構(gòu)造？？盆地中的底劈構(gòu)造？？泥底劈鹽底劈（硫酸鹽、碳酸鹽、石鹽）巖漿底劈2.底劈構(gòu)造核部巖性類型泥底劈鹽底劈（硫酸鹽、碳酸鹽、石鹽）巖漿底劈2.底劈構(gòu)造核部鹽底劈鹽底劈TopTagluStructuremapshowingtherelationshipbetweenthepresent-daycompressional泥底劈ReleasingBend釋放彎曲ReatrainningBend約束彎曲TopTagluStructuremapshowin3.底劈構(gòu)造核上部的正斷層常呈環(huán)狀或放射狀3.底劈構(gòu)造核上部的正斷層常呈環(huán)狀或放射狀樂(lè)東氣田——樂(lè)東l5-1構(gòu)造是鶯歌海盆地諸多泥底辟構(gòu)造之一樂(lè)東氣田——樂(lè)東l5-1構(gòu)造是鶯歌海盆地諸多泥底辟構(gòu)造之一油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure放射狀平形狀放射狀平形狀鹽構(gòu)造可以由以下6種機(jī)制觸發(fā)引起：①浮力作用;②差異負(fù)載作用;③重力擴(kuò)張作用;④熱對(duì)流作用;⑤擠壓作用;⑥伸展作用。核部由鹽類組成的底劈構(gòu)造稱為鹽丘。4.鹽丘的形成機(jī)制鹽構(gòu)造可以由以下6種機(jī)制觸發(fā)引起：核部由鹽類組成的底劈構(gòu)造稱撒哈拉穹窿——理查德構(gòu)造撒哈拉穹窿——理查德構(gòu)造油區(qū)構(gòu)造解析課件--9底辟構(gòu)造：Diapirs+structure理查德構(gòu)造——相當(dāng)于非洲之眼的眼球理查德構(gòu)造——相當(dāng)于非洲之眼的眼球非洲之眼是晚白堊紀(jì)堿性巖漿熱液上侵，沿灰質(zhì)白云巖陸架的環(huán)狀同生斷裂上侵，引發(fā)地表穹隆侵蝕和熱液卡斯特作用，由此而形成一個(gè)直徑40公里的眼珠狀構(gòu)造。巖漿上侵穹窿？非洲之眼是晚白堊紀(jì)堿性巖漿熱液上侵，沿灰質(zhì)白云巖陸架的環(huán)狀同含巖鹽盆地的鹽丘是是最常見(jiàn)的一類底劈構(gòu)造，與油氣關(guān)系密切。世界含鹽盆地分布含巖鹽盆地的鹽丘是是最常見(jiàn)的一類底劈構(gòu)造，與油氣關(guān)系密切。世鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)鹽丘的幾種剖面形態(tài)構(gòu)造位置與鹽構(gòu)造類型構(gòu)造位置與鹽構(gòu)造類型Asillustratedonthisseismicline,itisquiteobviousthesaltandoverburdenhavebeenshortened(compressionstillisgoingon)byacompressionaltectonicregimethatsomeassociatewithridgepushingforces.Thefaultsinthetopoftheantiformsarestrike-slipandnotnormalfaults.Timeslicesbetween3.0and3.2seconds,stronglysuggestthatsuchafaultselongatetheanticlineaxisalongthes2

二、鹽底劈構(gòu)造類型及特征鹽背斜1.擠壓鹽構(gòu)造AsillustratedonthisseismicFig.25-Thesaltweldinthecentralpartofthelinesuggeststhatbeforedeformationthesaltlayerwascontinuousbetweentheyellowandbrowninterval.Then,theinfra-saltstratawerelengthenedbynormal-faultscreatingpotentialvoidsthatwerefilledbysalt(“saltgrabens”)duetoalateralsaltflowage,whichcreatedawindowinthesaltlayer.Finally,acompressionaltectonicregimeshortenedthecoverinvertingthesaltgrabens.Fig.25-ThesaltweldintheItisinterestingtonoticethatindepth,thedistalthrustfaultcorrespondstotheseawardlimitofasaltbasin.Seaward,thesaltisallochthonousandformsasaltnappe,whichhasbeenreactivatedandshortenedprobablybyridgepushforces.Itisquiteobviousthatthethicknessofthesaltisapparentandduetothrusting.Somearguedthatthesaltbeingthickerintheultradeepoffshorewastheproofofanuniquepristinesaltbasinthatwaslatersplitintwo.Recently,suchaerroneouslyhypothesishasbeensystematicallyfalsified.推覆體

外來(lái)鹽ItisinterestingtonoticethTheregionalgeologicalsetti