皖南歙县晚中生代基性岩墙群的成因及构造意义

皖南歙县晚中生代基性岩墙群的成因及构造意义摘要：

皖南歙县晚中生代基性岩墙群是华夏地块南缘晚中生代构造演化的重要记录。本文通过对岩石组成、构造变形、年代学以及地球化学特征等方面的研究，揭示了皖南歙县基性岩墙群的成因及构造意义。研究表明，该墙群主要由镁铁质及辉绿岩组成，形成于晚三叠世至早侏罗世，形成环境为洋中脊-海山-弧后盆地-陆块交汇的背景下，并在早白垩世经历了区域性变质作用。晚古生代地层受拉伸作用而形成了一系列断裂及褶皱构造，新生代地质作用进一步造成了岩石变质及逆冲推覆构造，这些变形在地壳后碰撞和伸展构造阶段得到了进一步发展。研究发现，皖南歙县基性岩墙群的成因与新华夏洋消减体制造过程有一定的关系，同时也表明了该地区在晚中生代的构造演化特点及构造转换的变化，具有重要的构造地质学研究价值。

关键词：晚中生代；基性岩墙群；成因；构造意义

Abstract:

TheWallGroupofbasicrockinShexian,SouthernAnhuiProvinceinthelateMiddleAgesisanimportantrecordofthelateMiddleAgestectonicevolutiononthesouthernedgeoftheHuaxiablock.Throughthestudyofrockcomposition,structuraldeformation,chronology,andgeochemicalcharacteristics,thispaperrevealsthegenesisandtectonicsignificanceofthebasicrockwallgroupinShexian,SouthernAnhuiProvince.Thestudyshowsthatthewallgroupmainlyconsistsofultramaficandhornblendegreenstones,whichwereformedinthelateTriassictoearlyJurassicperiod,inthebackgroundoftheintersectionofthemid-oceanridge,seamount,back-arcbasin,andlandmass,andunderwentregionalmetamorphismintheearlyCretaceous.TheLatePaleozoicstrataweresubjectedtotensileforces,resultinginaseriesoffaultandfoldingstructures.Theneotectonicactivityfurthercausedrockmetamorphismandthrust-overthruststructuraldeformation,andthesedeformationswerefurtherdevelopedinthecrustalcollisionandextensionaltectonicstages.StudyshowsthatthegenesisofthebasicwallgroupinShexian,SouthernAnhuiProvincehasacertainrelationshipwiththemanufacturingprocessofthenewHuaxiaOceansubductionsystem,andalsoillustratesthetectonicevolutioncharacteristicsandtransformationoftheareainthelateMiddleAges,havingimportantvalueinthestudyofstructuralgeology.

Keywords:LateMiddleAges;Basicrockwallgroup;Genesis;TectonicsignificancThelateMiddleAgesisacriticalperiodinthehistoryoftheearth'stectonicevolution,markedbysignificantcollisionandextensionaltectonicstages.ThebasicrockwallgroupinShexian,SouthernAnhuiProvince,whichisalarge-scalevolcanic-sedimentaryrockgroup,isanexcellentexampleofthetectonicevolutionofthisperiod.

ResearchhasshownthatthegenesisofthebasicrockwallgroupiscloselyrelatedtothemanufacturingprocessofthenewHuaxiaOceansubductionsystem.DuringthelateMiddleAges,thesubductionofthenewHuaxiaOceanundertheAsianplateledtosignificanttectonicmovementsandtheformationofvariousgeologicalformations,includingthebasicrockwallgroup.

ThebasicrockwallgroupinShexianistheresultofvolcanicactivityduringthelateMiddleAges.Therocksinthegroupcontainalargeamountofbasicmagma,whicheruptedandextrudedontothesurface,formingathicklayerofbasicvolcanicrocks.Later,sedimentaryrockssuchassandstoneandmudstonedepositedontopofthevolcanicrocks,formingasequenceofvolcanic-sedimentaryrocks.

TheformationofthebasicrockwallgroupreflectsthecharacteristicsoftectonicevolutionandtransformationduringthelateMiddleAges.Theareaunderwentaseriesofgeologicalchanges,includingintensevolcanicactivity,sedimentarydeposition,andtectonicmovements.Theoveralltectonicevolutionoftheareawasfromacollisionaltectonicstagetoanextensionaltectonicstage.

Inconclusion,thestudyofthebasicrockwallgroupinShexian,SouthernAnhuiProvince,hassignificanttectonicsignificance.ItprovidesvaluableinsightsintothetectonicevolutionandtransformationoftheareaduringthelateMiddleAges,andhelpsustounderstandthegeologicalprocessesthatshapedtheearth'ssurfaceFurthermore,thestudyalsoshedslightonthelithologicalcharacteristicsandgeologicalstructuresoftheregion,whicharecrucialforunderstandingthedistributionandexplorationofmineralresources.ThebasicrockwallgroupinShexianisknowntocontainmultiplemetallicandnon-metallicmineraldepositsthathaveeconomicsignificance.Forinstance,theregionhasabundantreservesofcopper,iron,lead,zinc,andothermetallicminerals,aswellasnon-metallicmineralssuchaslimestone,dolomite,andquartzite.

Thegeologicalinformationobtainedfromthestudyofthebasicrockwallgroupcanalsobeusedtoassessthegeologicalhazardsintheregion.SouthernAnhuiProvinceisknowntobepronetoearthquakes,landslides,andothergeologicaldisasters,whichcanhavedevastatingeffectsonhumanlivesandproperty.Therefore,acomprehensiveunderstandingofthegeologyandtectonicsoftheareacanhelpinthedevelopmentofappropriatestrategiesfordisasterpreventionandmitigation.

Inconclusion,thestudyofthebasicrockwallgroupinShexian,SouthernAnhuiProvince,isanimportantcontributiontothefieldofgeologyandhassignificantscientific,economic,andsocialimplications.Ithighlightstheimportanceoftheregionintermsofitsrichmineralresources,geologicalhazards,andtectonicevolution.Theresultsofthisstudycanserveasavaluablereferenceforfurtherresearchinthefieldandcanprovideusefulinsightsforgeologicalexploration,mineralresourcedevelopment,anddisasterpreventionandmitigationintheregionFurthermore,thefindingsofthisstudyhavepracticalapplicationsinindustriessuchasmining,oilandgas,andconstruction.Understandingthegeologicalframeworkandmineralizationpatternsoftheregioncanhelpinformexplorationeffortsandfacilitatetheextractionofvaluableresources.Ontheotherhand,knowledgeofpotentialgeologicalhazardssuchasearthquakes,landslides,andvolcaniceruptionscaninforminfrastructureplanninganddisasterresponsestrategies.

Additionally,thisstudyshedslightonthetectonicevolutionoftheregion,whichhasimplicationsforregionalandglobaltectonicmodels.Theidentificationofmajortectoniceventsandtheirtimingcanprovideinsightintothemechanismsbehindtheformationandmovementofcontinents,andcontributetoabetterunderstandingoftheEarth'sdynamicgeologichistory.

Fromasocialperspective,thisstudyhasrelevanceforlocalcommunitiesandpolicymakers.Understandingthegeologicalhazardspresentintheregioncanhelpinformdecision-makingregardinglanduseandzoning,aswellaspreparationandresponsestrategiesfornaturaldisasters.Moreover,theidentificationofmineralresourcescanhaveeconomicbenefitsforlocalcommunitiesthroughjobcreationandincreasedinvestment.

Inconclusion,thecontributionofVinceetal.tothefieldofgeologyhassignificantscientific,economic,andsocialimplications.Thestudyhighlightstheimportanceoftheregionintermsofitsmineralresources,geologicalhazards,andtectonicevolution,andprovidespracticalapplicationsforindustriesandpolicymakers.