內蒙古獲各琦地區(qū)石英閃長巖年代學、地球化學特征及地質意義

內蒙古獲各琦地區(qū)石英閃長巖年代學、地球化學特征及地質意義摘要：

內蒙古獲各琦地區(qū)地處松遼地塊西緣，是顯生宙晚期特別是中-新元古代以來巖漿作用和構造演化的重要場所之一。本研究以該區(qū)域主要巖石石英閃長巖為研究對象，通過對其年代學、地球化學特征及其地質意義的探討，對該區(qū)域的地質演化過程進行了深入研究。該區(qū)域的石英閃長巖形成時間主要為古元古代晚期至新元古代早期，顏色以灰色、粉灰色和白色為主，具有較好的工程性能。各琦地區(qū)的石英閃長巖主要由斜長石-石英-鈉長石等礦物組成，具有低MgO、高SiO2、高Na2O+K2O等特征，地球化學分析表明其為富Si、虧P、富Na的高鉀鈣堿性系列。研究認為，各琦地區(qū)石英閃長巖的形成與該區(qū)域晚古生代-中-新元古代構造-巖漿作用密切相關，各琦洼地體在晚古生代-中元古代發(fā)育較強的張扭構造過程中，于巖漿極化地區(qū)形成了廣泛的石英閃長巖巖體，并經歷了巖漿-地殼相互作用，形成了釓、鈰虧損、Eu異常等特征。該區(qū)域石英閃長巖的研究對于深入認識該區(qū)域晚古生代-中-新元古代巖漿作用和構造演化過程具有重要意義。

關鍵詞：內蒙古；各琦地區(qū)；石英閃長巖；年代學；地球化學特征；地質意義。

Abstract:

GugeqiareainInnerMongoliaislocatedonthewesternedgeoftheSongliaoBlock,anditisanimportantplaceformagmaticactivityandtectonicevolutionsincetheMesozoicandCenozoiceras.Thisstudyfocusesonthemainrocktypeinthisregion-quartzdiorite,andexploresitschronology,geochemicalcharacteristics,andgeologicalsignificancetodeepenourunderstandingoftheregion'sgeologicalevolution.ThequartzdioritesinGugeqiareamainlyformedinthelatePaleoproterozoictoearlyNeoproterozoic,withgray,pink-gray,andwhiteasthemaincolorsandexcellentengineeringproperties.Themineralcompositionofthequartzdioriteismainlycomposedofplagioclase,quartz,andsodiumfeldspar,withlowMgO,highSiO2,andhighNa2O+K2O,indicatingthatitbelongstoahigh-potassiumcalc-alkalineseries.GeochemicalanalysisofthequartzdioritesinGugeqiarearevealsthattheyarerichinSi,deficientinP,andhavehighNacontent.ThestudysuggeststhattheformationofquartzdioritesinGugeqiareaiscloselyrelatedtothelatePaleozoic-Mesozoictectonicevolutionandmagmaticactivityintheregion.DuringthestrongdeformationofthelatePaleozoic-MesozoicZhangtuotectonicprocess,theGugeqiplutonformedanextensivequartzdioriteplutoninthemagmaticpolarizationareaandunderwentmagmatic-crustalinteraction,formingcharacteristicssuchasGdandCedeficiencyandEuanomaly.ThestudyofquartzdioritesinthisareaisofgreatsignificanceforadeeperunderstandingoftheMesozoicandCenozoicmagmaticactivityandtectonicevolutionintheregion.

Keywords:InnerMongolia;Gugeqiarea;quartzdiorite;chronostratigraphic;geochemicalcharacteristics;geologicalsignificanceTheGugeqiareainInnerMongoliaisknownforitsextensivequartzdioritepluton,whichisbelievedtohaveformedduringtheMesozoicandCenozoicmagmaticactivityintheregion.Theareaunderwentmagmatic-crustalinteraction,whichledtotheformationofuniquegeochemicalcharacteristicssuchasGdandCedeficiencyandEuanomaly.

Thestudyofthesequartzdioritesisofgreatsignificanceforunderstandingthegeologicalandtectonicevolutionoftheregion.Chronostratigraphicanalysisoftheareacanrevealthetimingofthemagmaticactivityandhelpunderstandthetectoniceventsthatledtotheformationofthepluton.

Thegeochemicalcharacteristicsofthequartzdioritescanalsoprovidevaluableinformationabouttheoriginandevolutionofthemagmasthatformedthem.TheGdandCedeficiencyandEuanomalysuggestthatthemagmasmayhaveinteractedwithcrustalmaterialduringtheirascent,leadingtothedepletionoftheseelements.

Overall,thestudyofthequartzdioritesintheGugeqiareacanshedlightonthecomplexgeologicalprocessesthathaveshapedtheregionovermillionsofyears.ItcanalsohelpusbetterunderstandthebroadercontextofmagmaticactivityandtectonicevolutioninInnerMongoliaandbeyondInadditiontotheinsightsprovidedbythechemicalandisotopicanalyses,thequartzdioritesintheGugeqiareaalsooffervaluableinformationabouttheirstructuralandtexturalfeatures.Specifically,therocksexhibitaporphyritictexture,whichischaracterizedbylargercrystalsembeddedinafiner-grainedmatrix.Thistextureindicatesatwo-stagecoolingprocess,wheretheinitialmagmaslowlycoolsandformslargercrystals,followedbyafastercoolingthatcreatesthematrix.

Moreover,thequartzdioritesalsodisplayseveraldeformationfeatures,suchasfractures,shearzones,andveins.Thesestructuresprovideevidenceforthecomplextectonichistoryoftheregion,whichhasbeensubjectedtomultipleepisodesofdeformationandmayhaveplayedaroleintheformationofthequartzdiorites.

Theveinsinparticularofferinsightsintothefluiddynamicsofthemagmaticsystem.Someveinsappeartohaveformedbytheinfiltrationofhot,metal-richfluidsintocracksintherock,whichthenprecipitatedasmineralgrains.Otherveins,knownastensiongashes,werelikelyformedbythestretchingandpullingoftherockduringdeformation,andmayhaveservedasconduitsforthemovementoffluids.

Inconclusion,thequartzdioritesintheGugeqiareaofferawealthofinformationaboutthegeologicalhistoryandtectonicevolutionofInnerMongolia.Throughchemical,isotopic,structural,andtexturalanalyses,scientistscanuncovertheprocessesthathaveshapedtheregionovermillionsofyears,includingmagmaticactivity,deformation,andfluidflow.Assuch,theserocksareavaluableresourceforunderstandingboththelocalandbroadercontextofEarth'sgeologyMoreover,thestudyoffluidsingeologicalprocessesisarapidlydevelopingfieldthatcanprovideinsightintotheformationandevolutionofawiderangeofgeologicalfeatures,includingmineraldeposits,hydrothermalsystems,andvolcaniceruptions.TheroleoffluidsinshapingtheGugeqiquartzdioritesisalsoofgreatinteresttogeologists.

Fluidscanplayacrucialroleintheformationofmagmaticrocks,influencingtheircomposition,texture,andstructure.Forexample,thepresenceofwaterandothervolatilesinmagmacanresultinexplosiveeruptions,asseeninthedevastatingeruptionofMountSt.Helensin1980.Furthermore,thereleaseoffluidsfrommagmaduringcoolingandsolidificationcanleadtotheformationofveinsandmineraldeposits.

InthecaseoftheGugeqiquartzdiorites,thestudyoffluidscanhelpexplaintheunusualcompositionandtextureoftheserocks,aswellastheirrelationshiptootherrockunitsintheregion.Onepossiblescenarioisthatfluidsplayedaroleintheformationofthequartzdioritesbyinteractingwithpre-existingrocks,causingpartialmeltingandtheformationofnewmineralassemblages.

Fluidscanalsobeinvolvedindeformationprocesses,whichcanresultinthedevelopmentofcomplexfoldingandfaultingpatternsinrocks.IntheGugeqiarea,thequartzdioritesareextensivelydeformed,withavarietyofstructurespresentatdifferentscales.Understandingtheroleoffluidsinthesedeformationprocessesiscrucialforreconstructingthetectonichistoryoftheregion.

Finally,thestudyoffluidsinthecontextoftheGugeqiquartzdioriteshasbroaderimplicationsforourunderstandingofEarth'sgeologyasawhole.Byinvestigatingthechemicalandisotopicsignaturesoffluidsindifferentgeologicalsettings,scientistscanreconstructthehistoryoftheEarth'soceansandatmosphere,aswellastheevolutionoflifeonourplanet.

Insummary,thestudyoffluidsintheGugeqiquartzdioritesisafascinatingandimportantfieldofresearchthatoffersvaluableinsightsintothegeo