2015第十届矿床模型大会-iocg presentation xian huayong chen

Ironoxide-Copper-Gold(IOCG)OreDeposits(铁氧化物铜金矿床）

陈华勇HuayongChen中国科学院广州地化所Model,casestudiesandexplorationguidelines（成矿模式，矿床典例研究及勘探应用）OlympicDamSouthAustralia(奥林匹克坝铜金铀矿）2015年11月西安workshopDoyouknowIOCG?

It’sveryfamousinAustralia!Howmuchweknow?(我们知道多少？）IOCGWhatcanweuse?(如何应用已知成果）What’snext?(今后研究重点）Outline(提纲）

Mantoverde,ChileOreDepositModel

(成矿模式）HistoryandDefinition（研究历史和定义）LocationandResources（分布及资源量）ModelingandProblems（模式及问题）2.CaseStudies

(典型矿床研究）OlympicDam,SouthAustraliaMantoverde,Chile3.ExplorationGuidelines

(勘探应用）Geologyfactors（地质特征应用）GeophysicsandGeochemistrymethods（地球物理及地球化学方法）ResearchHistory（研究历史）

IOCG:1992-2010Hitzmanetal.,1992(PrecambrianResearch:v.58,p.241-287)OlympicDamStudiesOreskesandEinaudi,1990,1992;Haynesetal.,1995BartonandJohnson,1996:Geology1996-2005:casestudiesCloncurry,Gawler,northernEurope,South&NorthAmerica,AfricaWilliamsetal.,2005(EconomicGeology100thAnniversaryVolume,p.371-405)Morecasestudies;modelmodificationDefinitionofIOCGDepositClan（IOCG矿床定义）

IOCG:DefinitionAclanofCu(-Au-Ag-U)depositscontainingabundanthypogeneironoxide(magnetiteand/orhematite)–含大量原生磁铁矿或赤铁矿的铜金（-银-铀等）矿床DefiningFeaturesofIOCGs(cf.Williamsetal.,2005;Skirrow,2004；Chen,2013)

Sulphur-poorCu-Au(-Fe)deposits

(贫硫铜金成矿系统)

Containlow-Tiironoxides(>10%)

(含大量低钛铁氧化物）

Hydrothermalorigin(breccia,vein,replacement)

(热液成因-角砾、脉体及交代结构发育）

Localstructuralcontrols(no“causitive”intrusions)

(受局部断裂控制，与岩体关系不明确）OthercommonfeaturesofIOCG（IOCG矿床其他主要特征）

IOCG:FeaturesRegionaltime-spaceassociationwithplutons

（与区域性侵入体有时空关系）

AssociationwithotherFeoxide-richrocks（与其他富铁建造关系密切）

Associationwithwidemetasomatism(Na,Na-Ca,K)（与大面积钠、钠-钙及钾化等交代作用相关）

VariableenrichmentinU,LREE,F,Co,Ba,Ag（具不同含量的铀，轻稀土、氟，钴，钡，银等元素）

Littlehydrothermalquartz(cf.porphyryCu)（与斑岩铜矿相比，热液石英相对较少）NotDefinitive（非定义性特征）Williams,2009,SGAIOCGshortcourseDistributionofIOCGDeposits（IOCG矿床分布）

IOCG:DistributionModifiedfromCorriveau,2007CloncurryOlympicDamNorbottenCentralAndesCarajásChina?GlobalResourcesofIOCGDeposits（IOCG矿床全球资源量）

IOCG:ResourcesDepositTonnage(Mt)Cu(%)Au(g/t)Ag(g/t)Othermetals(%)OlympicDam,Australia38101.00.53.6U(0.04)REESalobo,Brazil7890.960.5255Cristalino,Brazil5001.00.3Aitik,Sweden6060.380.21Candelaria,Chile4700.950.223.1Mantoverde,Chile4000.520.11MinaJusta,Peru3470.710.033.83ErnestHenry,Australia1671.10.54Co(0.05)ReferencesomittedIOCGModel:Alteration（IOCG蚀变模式）

IOCG:Model绢云母化（赤铁矿+绢云母+绿泥石+碳酸盐+石英）钾化

（钾长石或黑云母+磁铁矿+绿泥石+石英+阳起石）钠-钙蚀变

（钠长石或方柱石+阳起石+磁铁矿）ModifiedfromHitzmanetal.,1992HighlevelLowTemperatureLowlevelHighTemperatureOuterzone:Na-CaalterationIOCGModel:Na-Alteration（IOCG钠化蚀变特征）

IOCG:Model班状安山岩钠化蚀变序列（钠长石-阳起石-磁铁矿-磷灰石蚀变）EchoBay,Canada(Corriveau2009)Albitizedschistwithactinoliteveins钠化片岩及阳起石脉CloncurryDistrict,Australia(Williams2004)IOCGModel:Mineralization（IOCG矿化模式）

IOCG:ModelIOCGModel:Mineralization（IOCG矿化特征）

IOCG:ModelMagnetite（+hematite)–chalcopyrite-pyritebreccia磁铁矿（+赤铁矿）-黄铜矿-黄铁矿角砾ErnestHenry,Australia(Williams2009)Hematite-sericitebrecciawithchalcocite/bornite赤铁矿-绢云母角砾含辉铜矿及斑铜矿OlympicDam,Australia(Williams2004)IOCGModel:Ore-formingfluids（IOCG成矿流体）

IOCG:ModelIO+CGMagmatic-hydrothermal（岩浆热液流体）(Pollard,2001,2006;Sillitoe,2003)SimilartoPorphyry,SkarnsystemsNon-magmatichydrothermal（非岩浆热液流体）(BartonandJohnson,1996,2004;UllrichandClark,1999;Benavidesetal.,2007;Chenetal.,2010a;Chenetal.,2011)

Fe-oxidemelts（铁氧化物熔体）(NyströmandHenríquez,1994;Naslundetal.,2002;Chenetal.,2010b)Williamsetal.,2005IOCGModel:Timing（主要成矿时代）

IOCG:ModelCorriveau,2009LateArchean(晚太古代）CarajasDistrict,BrazilEarly-midProterozoic（早-中元古代）OlympicDam,CloncurryDistrict,Australia;Aitik,SwedenMesozoic(中生代）CentralAndesIOCGModel:TectonicEnvironment（IOCG成矿构造环境）

IOCG:ModelModifiedfromHitzman(2000)AoceaniccrustvolcanicrockssedimentsA:Subduction-relatedcontinentalmarginbasininversion

（俯冲板块边缘盆地闭合期）CentralAndesIOCGsBcontinentalcrustB:OrogenicBasinCollapse

（非俯冲造山带盆地闭合期）CloncurryDistrict,AustraliaCmantleunderplatingIntrusiverocksC:Anorogenicmagmatism

（非造山带陆内拉张环境）OlympicDam,AustraliaIOCGCaseStudies（矿床实例研究）OlympicDamCu-Au-USouthAustraliaMantoverdeCu(±Au)ChileAustralianIOCGDepositsWilliams,2004OlympicDamCu-Au-UDepositWilliams,2004IOCG:OlympicDam

3810Mtat1.0%Cu,0.5g/tAu,3.6g/tAg,0.04%UandabundantREE：38亿吨矿石量，品位铜1%；金0.5克/吨；银3.6克/吨，铀0.04%及大量稀土金属

Occursina7X5kmzoneofbrecciation/alterationcoredbyadiatremecomplex：矿体产于面积约为35平方公里的蚀变角砾岩中，中心为火山角砾岩筒

Majorfaultcontrol：受主断裂构造控制

HostrocksdominantlyProterozoicgranite：围岩主要为元古代花岗岩

Ultramafic,mafic,andfelsicdykesabundantinthediatremecomplex–syn-orpostdatebrecciasandmineralization：

与角砾及矿化同期或晚期的超基性、基性和酸性岩脉在矿区广泛发育

Dominantalteration-sericite+chlorite+hematite±quartz±siderite：主要蚀变组合为绢云母+绿泥石+赤铁矿及少量石英和菱铁矿

Magnetiteminor,deeper,early;Bariteandfluoriteabundant:仅含少量磁铁矿，位于深部；含大量重晶石和萤石

Stronglyzonedmineralization,chalcopyrite-bornite-chalcocitedominant:矿化分带明显，金属矿物以黄铜矿-斑铜矿-辉铜矿为主OlympicDamCu-Au-UDepositWilliams,2004IOCG:OlympicDamGawlerCratonGeologyandIOCGDepositsFromGeoscienceAustraliaOlympicDam：Structure（奥林匹克坝矿床构造）Skirrow,2006IOCG:OlympicDamOlympicDamGawlerCratonOlympicDam:DepositGeology（奥林匹克坝矿床地质）Williams,2004Hiltabagranite(1588Ma;花岗岩）Volcaniclasticrocks(火山碎屑岩）Granitebreccia(花岗岩角砾）Hematite-richbreccia(富赤铁矿角砾-矿化）Hematite-quartzbreccia(赤铁矿-石英角砾）IOCG:OlympicDamMafic,ultramaficandfelsicdykes(基性、超基性及酸性岩脉：<1592Ma

）bncpBornite-chalcopyriteinterface(斑铜矿-黄铜矿界面）ABOlympicDam:AlterationZonation（奥林匹克坝蚀变分带）IOCG:OlympicDamRegionalalteration

(区域蚀变）Skirrow,2006（钾长石-磁铁矿）（磁铁矿-阳起石-黄铁矿-碳酸盐）Incipientbrecciationofgranite

（花岗岩围岩弱角砾化-近矿区）（绿泥石-赤铁矿脉）hm-chl黄铜矿-赤铁矿角砾蚀变火山岩角砾赤铁矿-绢云母基质Hematitebreccias

（赤铁矿角砾-矿区）OlympicDam:MineralizationZonation（奥林匹克坝矿化分带）IOCG:OlympicDamSkirrow,2006Williams,2004Hematite-sericitebrecciawithchalcocite/bornite赤铁矿-绢云母角砾含辉铜矿及斑铜矿Bornite-chalcopyriteinterface(斑铜矿-黄铜矿界面）（黄铜矿-黄铁矿带）（斑铜矿-辉铜矿带）OlympicDam:Fluids/MetalsSources（奥林匹克坝流体/金属来源）IOCG:OlympicDamRegionalalteration-Early

（区域蚀变-早期）（磁铁矿-阳起石-黄铁矿-碳酸盐）Cu-Aumineralization-Late

（矿化-晚期）CAMassociatedfluids:Calcsilicate-alkalifeldspare-magnetite±sulfides钙硅酸盐-碱性长石-磁铁矿+少量硫化物HSCCassociatedfluids:Hematite-sericite-chlorite-carbonate-sulfides赤铁矿-绢云母-绿泥石-碳酸盐-硫化物Bastrakov,2002OlympicDam:Fluids/MetalsSources（奥林匹克坝流体/金属来源）IOCG:OlympicDamHowever,earlyCAMfluidscontainabundantCuBrinestoohottosaturateCu-minerals？（高温流体铜不易沉淀？）EfficientCudepositionrequirescoolingand/orgradientsinredox,pH,Cl,S

？（大量铜沉淀需要通过温度下降，以及氧化还原指数，pH值变化和Cl，S的加入？）Skirrow,2004Temperature(oC)Salinity(eq.wt.NaCl%)FluidMixing?流体混合cf.Haynesetal.,1995PIXEresultsOlympicDam:Ore-formingModel（奥林匹克坝成矿模式）IOCG:OlympicDamFluidmixingand/orfluidreplacementarea流体混合及/或流体交代区域Copperrangewebsite,2009IOCGDepositsinCentralAndes安第斯中部IOCG矿床MantoverdeChileChenetal.,2010MantoverdeCu(±Au)DepositIOCG:Mantoverde

400Mtat0.52%Cu,0.11g/tAu4亿吨矿石量，品位铜0.52%；金0.11克/吨Breccia-hostedandfaultcontrol：

矿化富集于角砾中；断裂控矿

HostrocksdominantlyJurassicvolcanicrocks：围岩主要为侏罗纪火山岩建造K-Fealterationdominated,spatiallyassociatedwithmineralizationbutpredateore主要蚀变为K-Fe交代，与矿化空间关系密切，但早于矿化

Mainhypogenemineralizationmineralassemblageishematite-chalcopyrite-calcite，strongsupergeneupgrading:主要原生矿物组合为赤铁矿-黄铜矿-方解石；次生富集显著

weakzonation,barrenmagnetitezonedeepseated

蚀变分带不明显，不含矿的磁铁矿带位于下部MantoverdeCu(±Au)DepositIOCG:MantoverdeBenavides,2006MantoverdeRegionalGeology（区域地质）IOCG:MantoverdeBenavidesetal.,2007Majorhostrocks主要赋矿围岩MantoverdeDepositGeology（矿区地质）IOCG:MantoverdeBenavidesetal.,2007mantoverdemainopenpitmineralization:specularhematiteveinsandbrecciasdominated矿化以镜铁矿脉及角砾为主MantoverdeOrebody（矿体特征）IOCG:MantoverdeBenavidesetal.,2007Cuorebodymagnetite120-126MaBarrenmagnetitebody无矿磁铁矿体Hematite-chalcopyriteorebody赤铁矿-黄铜矿矿体MantoverdeAlterationandMineralizationIOCG:MantoverdeBenavidesetal.,2007128Ma(U-Pb)117-121Ma(K-Ar)Mantoverde:RegionalAlteration（区域蚀变）IOCG:MantoverdeBenavides,2006RegionalalterationI:albitizationandhydrolysisalteration–albite+clay/illite+quartz±chlorite区域蚀变I：钠化及水解蚀变–钠长石+粘土/伊利石+石英±绿泥石RIRIIRegionalalterationII:Lowgrademetamorphism–chlorite+epidote+calcite+prehnite+pumpellyite+amphibole+quartz区域蚀变II：低级变质作用–绿泥石+绿帘石+方解石+葡萄石+绿纤石+角闪石+石英Mantoverde:Pre-oreAlteration（矿化前蚀变）IOCG:MantoverdeBenavides,2006K-Femetasomatism(StageI):K-feldspar+magnetite+apatite+amphibole+biotite钾-铁交代蚀变（StageI）：钾长石+磁铁矿+磷灰石+角闪石+黑云母Chloritebrecciation(StageII):chloritebrecciaedK-Fealteredclasts(StageI)

绿泥石化角砾（StageII）：绿泥石基质包裹早期钾-铁蚀变角砾Mantoverde:Mineralization（矿化特征）IOCG:MantoverdeBenavides,2006hematite+sulfidescementedbreccias(supergene)表生矿化赤铁矿角砾350350μHypogenemineralization:hematite+chalcopyriteafterpyriteandmagnetite原生铜矿化：赤铁矿+黄铜矿产于黄铁矿及磁铁矿之后Mantoverde:SulfurIsotope（硫同位素）IOCG:MantoverdeBenavides,2006Theδ34Svaluesofthehydrothermalfluidsincreaseddramaticallyfromearlytolateparageneticstages.流体

δ34S值从早期到晚期有很大提高，矿化阶段为最高值，达31.2‰+0.4to+3.0‰+9.1to+14.9‰+14.5to+25.1‰+21.4to+31.2‰Mantoverde:FeoxidesOxygenIsotopeIOCG:MantoverdeBenavides,2006Averageδ18Oforhematite=-0.5‰Averageδ18Oformagnetite=+2.3‰δ18Ofluidmagnetite=~+9‰(~450˚C).δ18Ofluidhematite=~+5‰(~250˚C)Magnetiteandhematiteequilibratedwithisotopicallydistinctfluids（磁铁矿与赤铁矿代表不同流体）Mantoverde:FluidEvolution（流体演化）IOCG:MantoverdeMagnetiteOrthoclaseBiotiteTourmalineTitaniteQuartzMuscoviteChloriteAnhydriteScapoliteRutileEpidoteHematitePyriteChalcopyriteGoldSideriteCalcite

STAGEI

STAGEIIORESTAGEIIISTAGEIVKandFeChlorite-Muscov.SpecularHematite-LatecalciteMetasomatism QuartzChalcopyrite veins500to550˚Cδ34Sfluid~0‰δ18Ofluid~+9‰300to350˚Cδ34Sfluid~+10to+15‰δ18Ofluid~+6to+10‰200to250˚Cδ34Sfluid~+25‰δ18Ofluid~+5‰Benavides,2006IOCG:MantoverdeMantoverde:FluidEvolution（流体演化）δ18OfluidδDfluidFluidmixinginorestageBenavides,2006IOCG:MantoverdeMantoverde:OreGeneticModel（成矿模式）Mantoverdeca.130MaBenavides,2006MantoverdeIOCG:MantoverdeMantoverde:OreGeneticModel（成矿模式）ca.117MaBenavides,2006CentralAndeanIOCGOreGeneticModel-中安第斯山IOCG成矿模式IOCG:CentralAndesChen,2008ExplorationofIOCGDeposits（IOCG矿床地质勘探）IOCG:ExplorationDiscoveryhistoriesofmajordepositsarealwaysimportantguidelinesforfutureexploration

重视主要矿床的发现过程对该类型矿床的进一步勘探大有帮助ExplorationGuidelines:Regionalgeologicalfeatures（勘探应用：区域地质特征）IOCG:ExplorationAlltemporallyassociatedwithregionalmagmatism,somespatiallyclosed

与同时期区域岩浆作用相关，部分空间关系紧密

Associatedwithregionalfaultsystem,orebodiescommonlycontrolledbyfaults(normalfaultsdominated)与区域断裂紧密相关；矿体常由断层控制（多为正断层）

RegionalNa-Caalterationcommondeveloped普遍发育区域钠-钙蚀变

commonlylocatedontheboundaryofbasins(CentralAndes)常位于盆地边缘（中安第斯山普遍）ExplorationGuidelines:StructureandIntrusions（勘探指示：断层及岩体）IOCG:ExplorationOlympicDamGawlerCratonHiltabaintrusionsOlympicDamFracturesinferredfromgravitymapSkirrow,2006ExplorationGuidelines:StructureandIntrusions（勘探指示：断层及岩体）IOCG:ExplorationWilliamsintrusionsCloncurryDistrictpmd*CRC,2005MajorIOCGdepositsareassociatedwithWilliamsgranitesandregionalstructures主要IOCG矿床与Williams花岗岩及区域断裂关系密切Alterationzonation–vectortoorebody（蚀变分带–矿体指向）IOCG:ExplorationWilliams,2009ErnestHenryKK(%)Cu>0.5wt%FeFe(%)PeripheralzoneNa-CaalterationadjacentzoneK-FealterationOrezoneCu-AumineralizationCommonbutnotalways:常见分带但非绝对标准Distal远带Ore矿带TextureZonation–vectortoorebody（矿化结构分带–矿体指向）IOCG:ExplorationMarketal.,2005Breccia(mineralization)矿化角砾岩体Veins脉状矿化Alteredhostrocks蚀变围岩Hostrocks围岩Ore矿带ErnestHenryTextureZonation–vectortoorebody（矿化结构分带–矿体指向）IOCG:ExplorationFairclough,2008OlympicDambrecciazonationHostrocksOreExplorationGuidelines:Geophysics（勘探应用：地球物理方法-物探）IOCG:ExplorationSkirrow,2006GawlerCraton-OlympicDamapplicationTotalMagneticIntensity磁异常强度分布Gravity重力异常分布ExplorationGuidelines:Geophysics（勘探应用：地球物理方法-物探）IOCG:ExplorationWilliams,2009OlympicDamDiscoveryFeaturesOlympicDamTotalMagneticIntensity奥林匹克坝地区磁异常强度分布However:Magneticanomalyhasadeeper(unknown)source磁异常来自深部未知区域Gravityanomalyiscausedbyhematiteintheorebody重力异常是由矿体中的赤铁矿导致ExplorationGuidelines:Geophysics（勘探应用：地球物理方法-物探）IOCG:ExplorationMagnetite-HematitemapinGawlerCratonSkirrow,2006OlympicDam1.5%“magnetite”

Includesallsusceptiblemineralsastheirmagnetiteequivalent1.5%磁铁矿边界线0.5%“haematite”

Includeshematite,

sulfides,gold,otherdenseminerals,andremanentmagnetisation0.5%赤铁矿边界线

3DinversionmapcombiningmagneticandgravitymapsExplorationGuidelines:Geophysics（勘探应用：地球物理方法-物探）IOCG:ExplorationCloncurryDistrict-ErnestHenryapplicationTotalMagneticIntensity磁异常强度分布ErnestHenryErnestHenryCloncurrypmd*CRC,2005ExplorationGuidelines:Geochemistry（勘探应用：地球化学方法-化探）IOCG:ExplorationHowever,neitherNa-norK-Fe-metasomatismcanbeusedasaccuratevectorforCu-Aumineralization–i.e.,canvectortobarrenmagnetitesystems但是，钠-钙蚀变或者钾-铁蚀变都不能准确定位矿体位置，因为他们可能指向不含矿的磁铁矿体AtMantoverdedistrict,K-FealterationindexcanidentifyfertileIOCGmineralization,butalsomixwithbarrenmagnetitesystems在Mantoverde地区，钾-铁蚀变指数可以鉴定出IOCG矿化区，但同时也“鉴定”出不含矿的磁铁矿体CerroNegro(249Mt@0.4%Cu0.15g/tAu)SantoDomingoSur(172Mt@0.57%Cu0.08g/tAu)Mantoverde(400Mt@0.52%Cu0.11g/tAu)PalmiraCarmenPirulaBenavidesetal.,2008ExplorationGuidelines:Geochemistry（勘探应用：地球化学方法-化探）IOCG:ExplorationWholerockδ18Ovs.alterationindexatMantoverdeBenavidesetal.,2008Mantoverde地区结合全岩氧同位素与蚀变强度指导找矿ExplorationGuidelines:Geochemistry（勘探应用：地球化学方法-化探）IOCG:ExplorationHowtotracetheexternalfluidsatMantoverde+0.4to+3.0‰+9.1to+14.9‰+14.5to+25.1‰+21.4to+31.2‰HydrolyticstageII–closelyassociatedwithmineralizationandrecordsIncursionofexoticfluids.(betweenStageIK-FemetasomatismandStageIIICumineralization)CanbetracedbyK/Al-Na/Alratioandδ18O-δDvalues:StageII与矿化紧密相关并且记录了流体混合过程，可以用地球化学手段探测ExplorationGuidelines:Geochemistry（勘探应用：地球化学方法-化探）IOCG:ExplorationHowtotracetheexternalfluidsatMantoverdeK-enrichment,Na-depletionK-depletionBenavidesetal.,2008ExplorationGuidelines:Geochemistry（勘探应用：地球化学方法-化探）IOCG:ExplorationHowtotracetheexternalfluidsatMantoverdeδD,‰(Fluid)CompositionalrangeforfluidinequilibriumwithChl-Ser-Hem-Calatca.350˚C.δ18O,‰(Fluid)IsotopiccompositionoffluidinequilibriumwithHematiteatca.200-250˚C.STAGEIIISTAGEIISTAGEICompositionalrangeforFluidinequilibriumwithMt(500˚C)Benavidesetal.,2008IOCGFutureStudies:今后研究重点IOCG:FutureOreDepositModeling（成矿模式构建）:stillalooseclanwithaconfuseddefinition,needmorecasestudiesandre-constructionofpresentmodels（定义及矿床系列不明确，需要更多的典型实例研究，已有的成矿模式需要更新；中国具有IOCG潜力，应该在该领域做出贡献，目前缺乏高水平的典例研究）Ore-formingFluidsEvolution（成矿流体演化）：

needdetailedparagenesisstudiesandmultiplemethodstotrackore-formingfluids（需要详细的成矿过程研究