贵州锦丰_烂泥沟_超大型金矿床构造解析及构造成矿作用

20078August,2007MINERALDEPOSITS264Vol.26No.4:025827106(2007)0420380217()X1,2,1,PhillipJ.Uttley2,TonyNorman2,2,3,4,3(1,100037;2SinoGoldMiningLimited,Sydney,NSW2000,Australia;3271,541100;4,100083),,()NSNWNE3,NW4(D22T2),;(T3)NSNWNE;(J1)NE,F22F3XEW,;(J22K),422,()1000m;;;;();:P618.51:AStructureanalysisandstructuralmetallogenesisofJinfeng(Lannigou)golddepositinGuizhouProvinceCHENMaoHong1,2,MAOJingWen1,PhillipJ.Uttley2,TonyNorman2,WULiuLing2,3,ZHENGJianMin4andQINYunZhong3(1InstituteofMineralResources,ChineseAcademyofGeologicalSciences,Beijing100037,China;2SinoGoldMiningLimited,Sydney,NSW2000,Australia;3No.271GeologicalPartyofGuangxi,Lingui541100,Guangxi,China;4.ChinaUniversityofGeosciences,Beijing100083,China)AbstractJinfeng,previouslyknownasLannigou,isthelargestknownCarlin2typegolddepositinYunnan2Guizhou2GuangxitriangleareaofsouthwesternChina.Thestructuralcharacteristics,evolutionandmetallogenesisoftheJinfenggolddepositweredetailedinthispaperbasedonthelargescaleminemappingandthetheoryandmethodX(1212010634001)SinoGoldMiningLimited(Australia),,1971,,E2mail:[e-mail]2007202209;2007206220;ofstructuralanalysis.Thestructurallinesofthisdepositwereclassifiedintothreegroups,trendingnorth2south,northwestandnortheastrespectively,inwhich,theNWtrendingstructurallinecontrolthestructuralframe2workofthedeposit.Thisdepositunderwentfourstructuraldeformationstages,i.e.,splittinginthecontempo2raneousstage,compressinginthecollisionalstage,lateralcomperessinginthepost2collisionalstageandextend2ingoflithosphere.Aseriesofcontemporaneousnormalfaults,suchasF1,F7whichwerenorthwest2southeasttrendanddippedeastinthedeposit,wereformedaroundthecarbonaterockplatformduringthesplittingstageofYoujiangbasin.Thesefaultsprovidedaprimarystructuralweaknessplanforthelatestructureaction.Be2causethereexistedLaizishandomewhichwasnearnorth2southstrike,compressiondirectionincollisionalstagechangedgraduallyfromeastwesttonortheastsouthwest,andmostobviousnorth2southandnorthweststrikestructurallineswereformedinthedeposit.Thatis,afold2faultstructuralassociationexistedwhichwascom2posedofstronglyoverturnedfoldsandreversefaults.Accompaniednortheasttrenddextralshearbelts,suchasF2,wereformedinthisstage.Theearlycontemporaneousfaults,likeF1,F7,correspondinglyexperienceddex2tralshear.Thecompressiondirectioninthepost2collisionstagewasnorthwest2southeasttrend,andrefoldedthefoldsgeneratedinthecollisionalstageintonortheaststrikesuperimposedfoldswhosehingevariedwiththebed2dingofearlystagefolds.Ontheotherhand,thecompressionareainnorth2southtrendandtheextensionareaineast2westtrendwereformedrespectivelyduetothestress’distributionontheXtypefaultsystemformedintheorogenicstage.BecauseitwasthefirmrockofLaizi2shandomeinthewest,theextensiontendedtohappenintheeastareaandresultedinF2’ssinistral2normalslippingandF3’sdextral2normalslipping,withtheore2bearingfluidenteringtheextensionarealeadingtogoldprecipitation.Afterthis,lithosphereextendedintheYanshanianstageinwhichthesmallreversefaultslightlycuttheformerstructure.Theabovefourmainstruc2turaldeformationstagesmatchedtheevolutionofYoujiangbasinfromsplittingtoclosingandcollapsing.Largescalegoldmetallogenesisoccurredatthestructuraltransitionfromcollisionalcompressiontoextensiontectonics.Thestructuraltrapformedbythrustinginthecollisionalorogenystageandthesplaysettinginthetransitionprocessfromcompressiontoextensionseemtohavebeenthemaincontrollingfactorsforlargescalecongregationanddepositionofgold.Structuralmetallogenesisisthemostrestrictedfactorfortheverticalextensionofasingleorebodyfor1000m.TheviewofstructuralmetallogenywouldprovideasignificanttheoreticalbasisforthedeepexplorationofCarlin2typegolddepositsinYunnan2Guizhou2Guangxitrianglearea.Keywords:geology,post2collision,structuralmetallogenesis,Carlin2typegolddeposit,Jinfeng(Lan2nigou)golddeposit,Guizhou()(),198620,/126125tO,,,,(1993)Hodkiewicz(2004)PNorman(2005)Q,(1995),,,OSinoGoldMiningLimited.15/Feb./2006.Announcements:SinogoldannouncesJinfengresourceexceeds4millionouncesgold[EB/OL].(Australia).QNormanT.2005.StructuralgeologyofAnbao,GaoluandJinfengmappingandloggingprocedures.MemosPreparedforSinoGoldLimitedGeocentricCompany(Australia).183264:(),,,,,,1,,,(,1985;,1980),,(,1986),(,1995;,1994),(2PhuNgu)(,2001;,2003),:();;(D2T),:(1)(1)NE,NW,NS(,1994),EW(,1986)(1995)NS,NSNWNE2,NS,NS,(2),,,(3),(,1992;1993),,,11;2;3;4;5/;6;7/;8/Fig.1RegionalgeologicalmapshowingthelocationoftheJinfeng(Lannigou)golddepositinGuizhouProvince1TurbiditeofTriassicbasinphase;2CarbonaterockandsandymudstoneofTriassicplatformphase;3LatePaleozoiccarbonaterockplatform;4Pre2Triassicstrata;5Regionalfault/fault;6Nappestructure;7Jinfeng(Lannigou)golddeposit/countyorcity;8Provincialboundary/nationalboundary,,,,,,,(),,,,,2,(1),,2832007,,27kmF2,NWF3(81%)NEF2,NWF3,550m,1000m,,,2(,1992),CO2(xCO20105),w(NaCleq)319%614%,(200300)(600105Pa1400105Pa),(Zhang,19