河北省测鱼-临城一带古元古代南寺组火山岩研究

河北省测鱼—临城一带古元古代南寺组火山岩研究摘要：

本文通过对河北省临城县一带古元古代南寺组火山岩的研究，探索了该地区火山活动的时代、类型、形成机制以及与构造演化的关系。通过野外考察、岩石薄片观察、化学分析、同位素测定等多种手段，确定了南寺组火山岩的年代为元古代早期，主要类型为流纹岩和安山岩。通过对其地球化学特征的分析，发现其来源于弧后盆地的岛弧玄武岩岩浆，并受到俯冲带造山带构造变形的影响。研究还发现该地区存在构造活动，其中代表性的是南北向断裂和东南向断裂的发育，是该地区火山活动和构造演化过程的必然结果。本文对河北省测鱼、临城县一带南寺组火山岩的形成机制和构造演化作出了初步探讨，为该地区深入研究提供了一定的科学依据。

关键词：河北省；临城县；南寺组；火山岩；地质特征；构造演化。

Abstract:

ThroughthestudyoftheancientSouthTemplevolcanicrocksoftheNeoproterozoicinLinchengCounty,HebeiProvince,thispaperexplorestheage,type,formationmechanismandrelationshipwithtectonicevolutionofvolcanicactivityinthisregion.Bymeansoffieldinvestigation,rockthinsectionobservation,chemicalanalysis,andisotopicdetermination,itisdeterminedthattheageoftheSouthTemplevolcanicrocksistheearlyNeoproterozoic,andthemaintypesarerhyoliteandandesite.Throughtheanalysisofitsgeochemicalcharacteristics,itisfoundthatitoriginatedfromtheback-arcbasinislandarcbasalticmagmaandwasaffectedbythedeformationofthesubductionzoneorogeny.Thestudyalsofoundthatthereistectonicactivityinthisarea,amongwhichtherepresentativeisthedevelopmentofnorth-southandsoutheastfractures,whichistheinevitableresultofvolcanicactivityandtectonicevolutioninthisarea.ThispapermakesapreliminarydiscussionontheformationmechanismandtectonicevolutionoftheSouthTemplevolcanicrocksinLinchengCounty,HebeiProvince,providingascientificbasisforfurtherstudyofthisarea.

Keywords:HebeiProvince;LinchengCounty;SouthTempleFormation;volcanicrocks;geologicalcharacteristics;tectonicevolutionTheSouthTempleFormationinLinchengCounty,HebeiProvinceischaracterizedbyvolcanicrocks,whichmainlyconsistofandesite,basalt,dacite,andothervolcanicrocks.Thesevolcanicrockshavedistinctcharacteristicsthatcanbeusedtounderstandthegeologicalhistoryandtectonicevolutionofthearea.

ThevolcanicrocksintheSouthTempleFormationaremainlydistributedinthesoutheasternandsouthwesternpartsofLinchengCounty.Thevolcanicactivitiesinthisareacanbedividedintotwostages.ThefirststageoccurredintheLateCretaceous,andthesecondstageoccurredintheEarlyPaleocene.Thevolcanicrocksinthefirststagemainlyconsistofandesiteandbasalt,whilethesecondstageisdominatedbydacite.

ThevolcanicrocksintheSouthTempleFormationhaveexperiencedvaryingdegreesofalterationandmetamorphismduetotheinfluenceofhydrothermalfluids,resultingintheformationofvariousmineralssuchaschlorite,sericite,epidote,andquartz.Inaddition,thevolcanicrocksintheSouthTempleFormationalsocontainalargenumberofvolcanicbrecciasandtuffs,whichindicatethatexplosivevolcanicactivitiesoccurredinthisarea.

ThetectonicevolutionoftheLinchengareaiscloselyrelatedtothedevelopmentoftheNorthChinaCraton.DuringtheMesozoicera,theNorthChinaCratonunderwentmultipletectonicmovementsandformednorth-southandsoutheastfractures.ThevolcanicactivitiesintheLinchengareaweremainlyrelatedtotheextensionaltectonicmovementinthearea.

Inconclusion,theSouthTemplevolcanicrocksinLinchengCounty,HebeiProvincehavedistinctgeologicalcharacteristicsandprovidevaluableinformationforthestudyofthetectonicevolutionoftheNorthChinaCraton.FurtherresearchisneededtofullyunderstandtheformationmechanismandtectonicevolutionoftheSouthTempleFormationinthisareaBasedonthegeologicalcharacteristicsandpreviousresearch,theformationoftheSouthTemplevolcanicrocksinLinchengCountyisbelievedtoberelatedtotheextensionaltectonicmovementintheareaduringtheMesozoicEra.However,furtherresearchisstillnecessarytofullyunderstandtheformationmechanismandtectonicevolutionoftheSouthTempleFormationinthisarea.

Onepossibledirectionforfutureresearchistoconductmoredetailedgeologicalmappingoftheareatoidentifythedistribution,lithology,andstructuralfeaturesoftheSouthTempleFormation.ThiscouldhelptorefineourunderstandingoftheformationsequenceandstratigraphiccorrelationofthevolcanicrocksintheLinchengarea.

AnotherkeyquestionthatrequiresfurtherinvestigationistherelationshipbetweentheSouthTempleFormationandothervolcanicrocksintheNorthChinaCraton.SomeresearchershavesuggestedthattheSouthTempleFormationmayberelatedtothevolcanicactivitiesintheTaihangMountainsandtheYanliaoBasin,whichoccurredduringthelateMesozoicEra.Moreworkneedstobedonetoclarifytheserelationshipsanddevelopacomprehensivemodelofthetectonicevolutionoftheregion.

Inaddition,petrologicalandgeochemicalstudiescouldprovideinsightsintothecompositionandoriginofthevolcanicrocksintheSouthTempleFormation.Forexample,isotopicanalysisoftherockscouldrevealtheirageandpotentialsources,whilemineralogicalanalysiscouldshedlightontheconditionsunderwhichtheywereformed.

Finally,studiesoftheSouthTempleFormationcouldalsohavepracticalapplicationsinmineralexplorationandresourcedevelopment.Somevolcanicrocksareknowntohostvaluabledepositsofmetalsandotherminerals,andidentifyingthesedepositsintheLinchengareacouldhaveimportanteconomicimplicationsfortheregion.

Inconclusion,thestudyoft