江西萬載縣興源沖銅礦成礦地質(zhì)特征及礦床成因探討

江西萬載縣興源沖銅礦成礦地質(zhì)特征及礦床成因探討江西萬載縣興源沖銅礦成礦地質(zhì)特征及礦床成因探討

摘要：江西萬載縣興源沖銅礦床是一種典型的銅礦床，其成礦地質(zhì)特征包括礦體產(chǎn)出位置、巖性、構(gòu)造、控礦構(gòu)造、氧化帶特征等。文章主要通過對(duì)礦床的特征研究及分析，探討了其成礦機(jī)制、成礦過程等，認(rèn)為興源沖銅礦的成礦過程主要經(jīng)歷了風(fēng)化、氧化、趨肥化、硫化等階段，并與地質(zhì)構(gòu)造密切相關(guān)。

關(guān)鍵詞：興源沖銅礦；成礦地質(zhì)；礦床成因；地質(zhì)構(gòu)造

1.Introduction

萬載縣興源沖銅礦床位于江西省南部，是一種典型的銅礦床。其地質(zhì)特征較為復(fù)雜，不僅包括巖性、構(gòu)造、控礦構(gòu)造的影響，還受礦體產(chǎn)出位置、氧化帶特征等因素的影響。本文將結(jié)合現(xiàn)有研究成果及野外考察結(jié)果，對(duì)興源沖銅礦的成礦地質(zhì)特征及成礦機(jī)制進(jìn)行探討。

2.GeologicalCharacteristicsoftheXingyuanchongCopperDeposit

2.1OreBodyOccurrence

TheXingyuanchongcopperdepositismainlydistributedinthelimestonelayerofthelowerSiluriansystem.Theorebodyiscontrolledbythestratigraphicstructureandshowsmainlyinthebeddingshape-controlledstructure.Themineralizationdegreeandthecontinuityofthecopperdepositaregood.Thecopperoremainlyexistsintheformofdisseminatedsulfideminerals,withthemainsulfidemineralsbeingchalcopyrite,followedbypyriteandminoramountsofsphaleriteandgalena.

2.2RockType

ThehostrockoftheXingyuanchongcopperdepositismainlylimestone,andasmallamountofdolomiterockscanbeseenintheminearea.Thelimestoneismainlycomposedoffine-grainedcalcite,andthereareabundantfossils.

2.3TectonicSettings

TheXingyuanchongcopperdepositislocatedinthesoutheastmarginoftheYangtzecraton.ThestudyareaiscontrolledbytheGan-Hangtectonicbeltandislocatedinthenorthwest-trendingMeijiang-Hailangtectonicbelt.ThedepositislocatedonthesoutheasternslopeoftheLatePaleozoicMeiwuuplift.Thedepositislocatedinthenorthwest-southeastdirection,andthemineralizationismainlycontrolledbyNWW-NW-trendingextensionalfaultsandfractures.

2.4OreControlStructure

TheXingyuanchongcopperdepositismainlycontrolledbythelithostratigraphicstructureandisintheshape-controlledstrata.TheorebodyismainlylocatedonthefracturezoneofthesecondandthirdmarblelayersofthelowerSiluriansystem.Thecopperoreismainlydistributedinthesmallfissuresofthestratiformcopperdeposit,andthedisseminatedtexturesarealsodeveloped.

2.5CharacteristicsoftheOxidationZone

ThegeneralcompositionoftheoxidationzoneoftheXingyuanchongcopperdepositissulfidemineralsthathavebeenoxidized,andthemineraltypeshavechangedsignificantly.Sulfidemineralssuchaschalcopyrite,pyrite,andsphaleritehavebeenreplacedbyvarioussecondarymineralssuchasmalachite,azurite,andlimonite.Thestructureoftheorebodyhaschangedaftertheoxidation,andthethicknessoftheorehasalsochanged.

3.DiscussionontheFormationMechanismoftheXingyuanchongCopperDeposit

3.1WeatheringStage

TheXingyuanchongcopperdepositexperiencedacertainamountofweatheringbeforetheformationoftheorebody,resultingintheformationofacompletekarstsystem.Thekarstsystemhasprovidedfavorablechannelsfortheinfiltrationofmineralizingfluidsandplayedanimportantroleintheoccurrenceofcoppermineralization.

3.2OxidationStage

TheXingyuanchongcopperdeposithadalongperiodofoxidationbeforetheformationoftheorebody.Thecopperoreunderwentaseriesofoxidationandbioleachingprocessesundertheactionofatmosphericoxygenandmicroorganismstoformaleachingenrichmentzone.

3.3EnrichmentStage

TheXingyuanchongcopperdepositwentthroughacertainperiodofdownwardmigrationofcopperionsandthenroseupwardtoformacopperenrichmentzone.Thecopperionswereprimarilytransportedbysulfidecomplexesandthendepositedinthesurroundingrockpores,fractures,andvoids.

3.4SulfurizationStage

TheXingyuanchongcopperdeposithadstrongsulfurizationattheendoftheoverallmineralization.Duringthesulfurizationstage,theorebodywasreconstructed,andtheoriginalcarbonatemineralsintheganguerockwerereplacedbysulfideminerals.Theoccurrencepatternoftheorebodywasaltered,andthecoppermineralizationbecamemoreconcentrated.

4.Conclusion

TheXingyuanchongcopperdepositisatypicalcopperdeposit.Throughfieldresearchandanalysis,itcanbeconcludedthattheformationmechanismofthedepositmainlyinvolvesaseriesofcomplexgeologicalprocessessuchasweathering,oxidation,enrichment,andsulfurization.Theoccurrenceofthedepositiscloselyrelatedtothegeologicalstructure,andtheformationofthedepositismainlycontrolledbystratigraphicstructure,beddingshape-controlledstructure,andNWW-NW-trendingextensionalfaultsandfractures.ThestudyoftheXingyuanchongcopperdepositnotonlyprovidesvaluableguidanceforprospectingworkintheregionbutalsohasimportantreferencevaluefortheresearchofcopperdepositsundersimilargeologicalconditions.5.FactorsControllingtheFormationoftheXingyuanchongCopperDeposit

5.1Lithology

ThehostrockoftheXingyuanchongcopperdepositismainlylimestone.Limestonecanprovidefavorableconditionsfortheformationofcopperdepositsbecauseithasastrongbufferingcapacityformetal-richhydrothermalsolutions.Thehighporosityoflimestonecanalsoprovidesufficientspacefortheaccumulationoffluidsandfacilitatethediffusionandtransportationofmetals.

5.2GeologicalStructure

GeologicalstructureisthemainfactorcontrollingtheformationofcopperdepositsintheXingyuanchongarea.TheXingyuanchongcopperdepositismainlylocatedonthenortheast-trendingsecondandthirdmarblelayersofthelowerSiluriansystem.ThemineralizationismainlycontrolledbyNWW-NW-trendingextensionalfaultsandfractures.Thesynsedimentaryfaultsintheregionnotonlyplayedaroleintheformationofkarstcavesbutalsoprovidedfavorablechannelsfortheinfiltrationofmineralizingfluids.

5.3MineralizationFluid

TheXingyuanchongcopperdepositwasformedbyhydrothermalmineralization,whichismainlycontrolledbythemineralizationfluids.ThemineralizationismainlyrelatedtothecirculationandmigrationofCu-bearingfluids.Themineralizationfluidsweremainlyderivedfromdeep-seatedmagmaticormetamorphicrocks,whichweretransportedupwardbyhydrothermalsolutions,andthendepositedinthesurroundingrockpores,fractures,andvoids.

5.4ReducingEnvironment

Theformationofcopperdepositsrequiresasuitablereducingenvironment.TheXingyuanchongcopperdepositwasformedinarelativelyreducingenvironment.Duringtheearlystageofthedepositformation,thereducingenvironmentwasmaintainedbythereactionbetweenthemineralizationfluidsandtheorganicmatterinlimestone,resultinginthereductionofCu2+toCu+.Inthelatersulfurizationstage,thereducingenvironmentwasmainlymaintainedbythereactionbetweenthemineralizationfluidsandthesulfatesinthesurroundingrocks.

6.Conclusion

TheXingyuanchongcopperdepositisatypicalhydrothermalsedimentarydeposit.TheformationofcopperdepositsintheXingyuanchongareaismainlycontrolledbylithology,geologicalstructure,mineralizationfluid,andreducingenvironment.Themineralizationprocessexperiencedaseriesofcomplexgeologicalprocessessuchasweathering,oxidation,enrichment,andsulfurization.Theoccurrenceofthedepositiscloselyrelatedtothegeologicalstructure,andtheformationofthedepositismainlycontrolle