构造地质学双语joints

构造地质学双语joints公司内部档案编码：[OPPTR-OPPT28-OPPTL98-OPPNN08]Chapter4JointKeywordsBeddingjointsStrikejointsDipjointsObliquejointsFracturesDiagonaljoint层节理走向节理倾向节理斜向节理破裂斜节理JointJointSystematicNon-systematicPlumosesetssystemjoints:jointsstructure节理组节理系系统节理非系统节理羽饰构造ShearjointTensionjointen-echelonLongitudinaljointsTransversejoints剪节理张节理雁列（脉，节理）纵节理横节理HackleplumeaxistensiongashesRegionaljointStylolites羽脉羽轴张裂脉区域性节理缝合线Fracturesaresurfacesalongwhichrocksormineralshavebroken.Joints,beoneofthemostcommonlyfoundpervasivemesoscopicstructure,arethefractureswithoutapparentdisplacementinrocks.Thesediscontinuitieswillbeencounteredinmanyengineeringtasksinvolvingnationalandlocalneeds.Cracksinrockscarrygroundwaterfarmoreefficientlythanthebulkrockwithitsrelativelylowpermeability.Incontrasttherecoveryofgeothermalenergyrequirescracksinhotrocksothatheatfluidspumpedalongthecrackscanactasthemediumwithwhichheatedwateristransportedtothesurface.Therecoveryofpetroleumisbestaccomplishedwhenwellscutafracturednetworkcontaininglargeamountsofpetroleum.Theproperty,orientationanddistributionofjointsarecloselyrelatedtothefolds,faultsandregionalstructures.So,thestudiesofjointsareveryhelpfultoanalyzethegeologicalstructure.1.ClassificationofjointsTheclassificationofjointsisbasedontwomainfactors:thegeometricalrelationshipwithotherrelatedstructures.Mechanismsofthejoint'sforming.Jointsarerelativelybelongingtosmall-scalestructures.Theorientationsofjointsoftenhavegeometricalrelationshipwithotherstructures.⑴A:Therelationshipbetweenjointsstrikeandsenseofassociatedstrata.Strikejoints.Strikeofthejointisparalleltothestrikedirectionofbed.Dipjoints.Thestrikeofthejointisperpendiculartothestrikeofbed.Obliquejoints.Thestrikeofthejointisobliquetothestrikeofbed.Beddingjoints.Jointplaneisparalleltothebeddingplanes.

B:TherelationshipbetweenjointandfoldaxisLongitudinaljoints:Strikeofthejointisparalleltothefoldaxes.Transversejoints:Strikeofthejointisperpendiculartofoldaxes.Diagonaljoint:Strikeofthejointisaobliquetofoldaxes.(2)AccordingtothemechanismofjointsShearjoint.Incompression,jointsdevelopintheconjugatesheardirections(theorientationofsymmetricfractureplanes)makingtheloweranglewiththemajorprincipalstressdirection.Shearjointsareoftengrooved,striated,polishedorslickensidedbyevensmallamountsofsheardisplacement.Conjugateshearfracturesmaybeusedtomapmaximumprincipalstressinthevicinityofafaultzone.JointsetCoinpre^sioiiShearjointTensilejointShearjointIntension,jointsdevelopbystretchingnormaltothetensilestressdirectionwhichisusuallytheminorprincipalstress.Tensionjointsarerough(unlesssubsequentlyweathered).Incoarsegrainedrockssuchsurfacesmaybeveryrough.Tensionaljointincludecolumnarjointsinbasalts,dykesandsills,tensiongashes,calciteandquartzfilledveins.Extensionjointsarenotonelongdiscontinuitybutratherseveraljointsthatformend-to-endinajointzone.(3)JointsetsandjointsystemsJointsets:manyadjacentjointswithsimilargeometryandorientation.Systematicjointsroughlyplanar,sub-parallelorientations,regularspacing.Non-systematicjointscurvedandirregularingeometry,usuallyterminateagainstsystematicjoints.Jointsystemmadeupoftwoormoresetsofjoints,maybepersistentoverlargeregions.Thegeometryofjointsystemsaredescribedwiththefollowingmeasurementsandobservations:orientationscaleandshape,spacingandapertureintersectionsandterminationsspatialpatterns.

systematicjoints3.Surfacemorphologysystematicjoints3.SurfacemorphologySomejointsurfacesdisplaybeautifulsurfaceornamentation,thatisplumestructure.Plumosestructureconsistsofanumberofmorphologicalcomponents:plumeaxis,hackles,andfringezone.Curvedhacklemarksradiateoutwardfromthepoint(origin)wherethejointoriginated.Thesestructuresindicatethepropagationdirectionofthejoint.Thefringeofajointmaybemarkedbycloselyspaceden-echelonjointsobliquetothemainjointface.OnginMtrrorMistHackJafringeTvuislhacklePlume'themainjointface.OnginMtrrorMistHackJafringeTvuislhacklePlume'a.xiTraceof+wi3tFt^cklc3.EnechelonveinsVeinsarefracturefilledwithaprecipitate,commonlyquartzorcalcite,rarelymud.Enechelonveiniskindofvein

whichcanbefoundinmanyrocks,especiallyincarbonaterocks.Enechelonareparallelorsubparallel,closely-spaced,overlappingorstep-likeminorstructuralfeaturesinrock,suchasfaultsandtensionfractures,thatareobliquetotheoverallstructuraltrendSigmoidaltensiongashes,generallyS-orZ-shaped,formalongzonesofductileshear.Thistypeofextensionalfractureisusuallymineral-filledandformenechelonarraysalongtheshearzone.EnEchelontensionfractures(gashes)mayindicatethedirectionofdisplacementbytwofeatures:1)Sigmoidalprofilesoffractures,and2)offsetdirectionofvein-filledprofilesoffractures,and2)offsetdirectionofvein-filledfractures〃Thesigmoidalprofilesoffracturesarecross-sectionalThesigmoidalprofilesoffracturesarecross-sectionalviewsthataidindeterminingthedirectionofrotation.Theviewsthataidindeterminingthedirectionofrotation.TheprofilesresembleanS-shapedfeaturewiththetipspointinginprofilesresembleanS-shapedfeaturewiththetipspointinginthedirectionofrotation,eitherclockwiseorcounterclockwise.Thegashfracturesformasextensionalfracturesthatareperpendiculartotheminimumcompressivestress,sigma3(seediagram).Thefracturesmayberotatedbyductiledeformationeitherduringorafterformation.Asgashfracturesdevelopatdifferenttimesofductileshearingtheyshowdifferentamounts

ofrotation.Sincesigma3isnormaltotheunrotatedportionofthegashfracture,eitherthetipsofthesigmoidalfractureorthenewlyformedfracturestellsthestressorientation.Theyoungestfracturesmaynotshowanyorverylittlerotation.(seediagram).4.StylolitesStylolitesareirregularsurfacesthatcommonlyappearasStylolitesaredark,jaggedlinesonexposedsurfacesofcarbonaterock.Theirdark,jaggedlinesoriginisusuallyattributedtosolutionthatoccursafterthehostrockwasformed.Thedarklayersareinsolubleresidues.Stylolitesoftencrossthewholerock,cuttinggrains,matrixandcementstylolitesbelongtopressuresolutionstructuresformedatstrainlocalisationsiteswithinrocks,andcanbeusedtoindicatethestressdirection.4.RelationshipsBetweenJointsandOtherStructuresColumnarjointspolygonalfracturesformedduringcoolingoflavaflowsandshallowintrusions.Duetotensilestressessetupasigneousrockcontractsduringcooling.jointsaregenerallytensilefractures.jointsaregenerallytensilefractures.jointsaregenerallytensilefractures.jointsaregenerallytensilefractures.Sheet(orexfoliatior)joints:curvedjointsthataresubparalleltothetopography.Earthsurfacesiserodedandrelievesverticalstressbutlateralstressisnotreducedproportionally.Thereforeverticalstressbecomesminimumprincipalstressandjointsformperpendiculartolandsurface.Shrinkageofcoolingplutons(largehomogenousigneousmasses)mayalsoproducesheetingjointsorexfoliation.玲机P『*ril玲机P『*rilJointsassociatedwithfoldsSeveralsetsofjointsmaydevelopinresponsetofolding.Conjugateshearjointsobliquetothefoldaxisaredevelpoedbycompression.Tensionjointscandevelopduetobending,particularlyinthevicinityofthefoldhinge.Jointsparalleltothestrikeofthefoldaxisarecalledstrikejoints;thoseparalleltothelimbdipareknownasdipjoints.Suchexistingjoints.Becausefracturestopsatfreesurfaceofexistingjoints.Becausefracturestopsatfreesurfaceoftensionjointsstrikejointdipjointobliquejoints(cosnjugateshearjoints)maximumprincipaltensionjointsstrikejointdipjointobliquejoints(cosnjugateshearjoints)maximumprincipaldirectionJointsassociatedwithfaultshighstresslevelsinthehangingwallandfootwallofafaultcanresultintheformationofconjugateshearjoints,withonesetparalleltothefaultplaneandtheothersetatanobliqueangleofabout65?.Jointsinplutonicrocksseveraljointsetsarecommonlyobservedinplutons.Suchjointsarethoughttoberelatedtostressessetupduringcoolingoftherockmasswithinaregionalstressfield.shsetingjointsI□shsetingjointsI□ngltud1neIJointscroesJalntsRegionaljointsetsremarkablyconsistentsetsofjointsareobservedattheregionalscale,particularlyinweaklydeformedsedimentary""platformsequences".Suchjointsare

usuallytectonicjointsthatisextensionaljointsformedduetohorizontaltectoniccompressionunderconditionsofelevatedporefluidpressure.withJointsandVeinsintheFieldStudywayofjointsvarieswithdifferentpurposes,butingeneral,allofthestudiesonjointsarebasedonthemeasurement,observation,andstatistics.Localities.Theobservationlocalitiesshouldhavethefollowingfeatures:WellexposedoutcropsClearlyobservablestructureBeddingswithtableorientationClearrelationshipofjointsetsandjointsystems.ContentsofobservationGeologicalbackgr