2015第十屆礦床模型大會-iocg presentation xian huayong chen

Ironoxide-Copper-Gold(IOCG)OreDeposits(鐵氧化物銅金礦床）

陳華勇HuayongChen中國科學院廣州地化所Model,casestudiesandexplorationguidelines（成礦模式，礦床典例研究及勘探應(yīng)用）OlympicDamSouthAustralia(奧林匹克壩銅金鈾礦）2015年11月西安workshopDoyouknowIOCG?

It’sveryfamousinAustralia!Howmuchweknow?(我們知道多少？）IOCGWhatcanweuse?(如何應(yīng)用已知成果）What’snext?(今后研究重點）Outline(提綱）

Mantoverde,ChileOreDepositModel

(成礦模式）HistoryandDefinition（研究歷史和定義）LocationandResources（分布及資源量）ModelingandProblems（模式及問題）2.CaseStudies

(典型礦床研究）OlympicDam,SouthAustraliaMantoverde,Chile3.ExplorationGuidelines

(勘探應(yīng)用）Geologyfactors（地質(zhì)特征應(yīng)用）GeophysicsandGeochemistrymethods（地球物理及地球化學方法）ResearchHistory（研究歷史）

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礦床定義）

IOCG:DefinitionAclanofCu(-Au-Ag-U)depositscontainingabundanthypogeneironoxide(magnetiteand/orhematite)–含大量原生磁鐵礦或赤鐵礦的銅金（-銀-鈾等）礦床DefiningFeaturesofIOCGs(cf.Williamsetal.,2005;Skirrow,2004；Chen,2013)

Sulphur-poorCu-Au(-Fe)deposits

(貧硫銅金成礦系統(tǒng))

Containlow-Tiironoxides(>10%)

(含大量低鈦鐵氧化物）

Hydrothermalorigin(breccia,vein,replacement)

(熱液成因-角礫、脈體及交代結(jié)構(gòu)發(fā)育）

Localstructuralcontrols(no“causitive”intrusions)

(受局部斷裂控制，與巖體關(guān)系不明確）OthercommonfeaturesofIOCG（IOCG礦床其他主要特征）

IOCG:FeaturesRegionaltime-spaceassociationwithplutons

（與區(qū)域性侵入體有時空關(guān)系）

AssociationwithotherFeoxide-richrocks（與其他富鐵建造關(guān)系密切）

Associationwithwidemetasomatism(Na,Na-Ca,K)（與大面積鈉、鈉-鈣及鉀化等交代作用相關(guān)）

VariableenrichmentinU,LREE,F,Co,Ba,Ag（具不同含量的鈾，輕稀土、氟，鈷，鋇，銀等元素）

Littlehydrothermalquartz(cf.porphyryCu)（與斑巖銅礦相比，熱液石英相對較少）NotDefinitive（非定義性特征）Williams,2009,SGAIOCGshortcourseDistributionofIOCGDeposits（IOCG礦床分布）

IOCG:DistributionModifiedfromCorriveau,2007CloncurryOlympicDamNorbottenCentralAndesCarajásChina?GlobalResourcesofIOCGDeposits（IOCG礦床全球資源量）

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蝕變模式）

IOCG:Model絹云母化（赤鐵礦+絹云母+綠泥石+碳酸鹽+石英）鉀化

（鉀長石或黑云母+磁鐵礦+綠泥石+石英+陽起石）鈉-鈣蝕變

（鈉長石或方柱石+陽起石+磁鐵礦）ModifiedfromHitzmanetal.,1992HighlevelLowTemperatureLowlevelHighTemperatureOuterzone:Na-CaalterationIOCGModel:Na-Alteration（IOCG鈉化蝕變特征）

IOCG:Model班狀安山巖鈉化蝕變序列（鈉長石-陽起石-磁鐵礦-磷灰石蝕變）EchoBay,Canada(Corriveau2009)Albitizedschistwithactinoliteveins鈉化片巖及陽起石脈CloncurryDistrict,Australia(Williams2004)IOCGModel:Mineralization（IOCG礦化模式）

IOCG:ModelIOCGModel:Mineralization（IOCG礦化特征）

IOCG:ModelMagnetite（+hematite)–chalcopyrite-pyritebreccia磁鐵礦（+赤鐵礦）-黃銅礦-黃鐵礦角礫ErnestHenry,Australia(Williams2009)Hematite-sericitebrecciawithchalcocite/bornite赤鐵礦-絹云母角礫含輝銅礦及斑銅礦OlympicDam,Australia(Williams2004)IOCGModel:Ore-formingfluids（IOCG成礦流體）

IOCG:ModelIO+CGMagmatic-hydrothermal（巖漿熱液流體）(Pollard,2001,2006;Sillitoe,2003)SimilartoPorphyry,SkarnsystemsNon-magmatichydrothermal（非巖漿熱液流體）(BartonandJohnson,1996,2004;UllrichandClark,1999;Benavidesetal.,2007;Chenetal.,2010a;Chenetal.,2011)

Fe-oxidemelts（鐵氧化物熔體）(Nystr?mandHenríquez,1994;Naslundetal.,2002;Chenetal.,2010b)Williamsetal.,2005IOCGModel:Timing（主要成礦時代）

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成礦構(gòu)造環(huán)境）

IOCG:ModelModifiedfromHitzman(2000)AoceaniccrustvolcanicrockssedimentsA:Subduction-relatedcontinentalmarginbasininversion

（俯沖板塊邊緣盆地閉合期）CentralAndesIOCGsBcontinentalcrustB:OrogenicBasinCollapse

（非俯沖造山帶盆地閉合期）CloncurryDistrict,AustraliaCmantleunderplatingIntrusiverocksC:Anorogenicmagmatism

（非造山帶陸內(nèi)拉張環(huán)境）OlympicDam,AustraliaIOCGCaseStudies（礦床實例研究）OlympicDamCu-Au-USouthAustraliaMantoverdeCu(±Au)ChileAustralianIOCGDepositsWilliams,2004OlympicDamCu-Au-UDepositWilliams,2004IOCG:OlympicDam

3810Mtat1.0%Cu,0.5g/tAu,3.6g/tAg,0.04%UandabundantREE：38億噸礦石量，品位銅1%；金0.5克/噸；銀3.6克/噸，鈾0.04%及大量稀土金屬

Occursina7X5kmzoneofbrecciation/alterationcoredbyadiatremecomplex：礦體產(chǎn)于面積約為35平方公里的蝕變角礫巖中，中心為火山角礫巖筒

Majorfaultcontrol：受主斷裂構(gòu)造控制

HostrocksdominantlyProterozoicgranite：圍巖主要為元古代花崗巖

Ultramafic,mafic,andfelsicdykesabundantinthediatremecomplex–syn-orpostdatebrecciasandmineralization：

與角礫及礦化同期或晚期的超基性、基性和酸性巖脈在礦區(qū)廣泛發(fā)育

Dominantalteration-sericite+chlorite+hematite±quartz±siderite：主要蝕變組合為絹云母+綠泥石+赤鐵礦及少量石英和菱鐵礦

Magnetiteminor,deeper,early;Bariteandfluoriteabundant:僅含少量磁鐵礦，位于深部；含大量重晶石和螢石

Stronglyzonedmineralization,chalcopyrite-bornite-chalcocitedominant:礦化分帶明顯，金屬礦物以黃銅礦-斑銅礦-輝銅礦為主OlympicDamCu-Au-UDepositWilliams,2004IOCG:OlympicDamGawlerCratonGeologyandIOCGDepositsFromGeoscienceAustraliaOlympicDam：Structure（奧林匹克壩礦床構(gòu)造）Skirrow,2006IOCG:OlympicDamOlympicDamGawlerCratonOlympicDam:DepositGeology（奧林匹克壩礦床地質(zhì)）Williams,2004Hiltabagranite(1588Ma;花崗巖）Volcaniclasticrocks(火山碎屑巖）Granitebreccia(花崗巖角礫）Hematite-richbreccia(富赤鐵礦角礫-礦化）Hematite-quartzbreccia(赤鐵礦-石英角礫）IOCG:OlympicDamMafic,ultramaficandfelsicdykes(基性、超基性及酸性巖脈：<1592Ma

）bncpBornite-chalcopyriteinterface(斑銅礦-黃銅礦界面）ABOlympicDam:AlterationZonation（奧林匹克壩蝕變分帶）IOCG:OlympicDamRegionalalteration

(區(qū)域蝕變）Skirrow,2006（鉀長石-磁鐵礦）（磁鐵礦-陽起石-黃鐵礦-碳酸鹽）Incipientbrecciationofgranite

（花崗巖圍巖弱角礫化-近礦區(qū)）（綠泥石-赤鐵礦脈）hm-chl黃銅礦-赤鐵礦角礫蝕變火山巖角礫赤鐵礦-絹云母基質(zhì)Hematitebreccias

（赤鐵礦角礫-礦區(qū)）OlympicDam:MineralizationZonation（奧林匹克壩礦化分帶）IOCG:OlympicDamSkirrow,2006Williams,2004Hematite-sericitebrecciawithchalcocite/bornite赤鐵礦-絹云母角礫含輝銅礦及斑銅礦Bornite-chalcopyriteinterface(斑銅礦-黃銅礦界面）（黃銅礦-黃鐵礦帶）（斑銅礦-輝銅礦帶）OlympicDam:Fluids/MetalsSources（奧林匹克壩流體/金屬來源）IOCG:OlympicDamRegionalalteration-Early

（區(qū)域蝕變-早期）（磁鐵礦-陽起石-黃鐵礦-碳酸鹽）Cu-Aumineralization-Late

（礦化-晚期）CAMassociatedfluids:Calcsilicate-alkalifeldspare-magnetite±sulfides鈣硅酸鹽-堿性長石-磁鐵礦+少量硫化物HSCCassociatedfluids:Hematite-sericite-chlorite-carbonate-sulfides赤鐵礦-絹云母-綠泥石-碳酸鹽-硫化物Bastrakov,2002OlympicDam:Fluids/MetalsSources（奧林匹克壩流體/金屬來源）IOCG:OlympicDamHowever,earlyCAMfluidscontainabundantCuBrinestoohottosaturateCu-minerals？（高溫流體銅不易沉淀？）EfficientCudepositionrequirescoolingand/orgradientsinredox,pH,Cl,S

？（大量銅沉淀需要通過溫度下降，以及氧化還原指數(shù)，pH值變化和Cl，S的加入？）Skirrow,2004Temperature(oC)Salinity(eq.wt.NaCl%)FluidMixing?流體混合cf.Haynesetal.,1995PIXEresultsOlympicDam:Ore-formingModel（奧林匹克壩成礦模式）IOCG:OlympicDamFluidmixingand/orfluidreplacementarea流體混合及/或流體交代區(qū)域Copperrangewebsite,2009IOCGDepositsinCentralAndes安第斯中部IOCG礦床MantoverdeChileChenetal.,2010MantoverdeCu(±Au)DepositIOCG:Mantoverde

400Mtat0.52%Cu,0.11g/tAu4億噸礦石量，品位銅0.52%；金0.11克/噸Breccia-hostedandfaultcontrol：

礦化富集于角礫中；斷裂控礦

HostrocksdominantlyJurassicvolcanicrocks：圍巖主要為侏羅紀火山巖建造K-Fealterationdominated,spatiallyassociatedwithmineralizationbutpredateore主要蝕變?yōu)镵-Fe交代，與礦化空間關(guān)系密切，但早于礦化

Mainhypogenemineralizationmineralassemblageishematite-chalcopyrite-calcite，strongsupergeneupgrading:主要原生礦物組合為赤鐵礦-黃銅礦-方解石；次生富集顯著

weakzonation,barrenmagnetitezonedeepseated

蝕變分帶不明顯，不含礦的磁鐵礦帶位于下部MantoverdeCu(±Au)DepositIOCG:MantoverdeBenavides,2006MantoverdeRegionalGeology（區(qū)域地質(zhì)）IOCG:MantoverdeBenavidesetal.,2007Majorhostrocks主要賦礦圍巖MantoverdeDepositGeology（礦區(qū)地質(zhì)）IOCG:MantoverdeBenavidesetal.,2007mantoverdemainopenpitmineralization:specularhematiteveinsandbrecciasdominated礦化以鏡鐵礦脈及角礫為主MantoverdeOrebody（礦體特征）IOCG:MantoverdeBenavidesetal.,2007Cuorebodymagnetite120-126MaBarrenmagnetitebody無礦磁鐵礦體Hematite-chalcopyriteorebody赤鐵礦-黃銅礦礦體MantoverdeAlterationandMineralizationIOCG:MantoverdeBenavidesetal.,2007128Ma(U-Pb)117-121Ma(K-Ar)Mantoverde:RegionalAlteration（區(qū)域蝕變）IOCG:MantoverdeBenavides,2006RegionalalterationI:albitizationandhydrolysisalteration–albite+clay/illite+quartz±chlorite區(qū)域蝕變I：鈉化及水解蝕變–鈉長石+粘土/伊利石+石英±綠泥石RIRIIRegionalalterationII:Lowgrademetamorphism–chlorite+epidote+calcite+prehnite+pumpellyite+amphibole+quartz區(qū)域蝕變II：低級變質(zhì)作用–綠泥石+綠簾石+方解石+葡萄石+綠纖石+角閃石+石英Mantoverde:Pre-oreAlteration（礦化前蝕變）IOCG:MantoverdeBenavides,2006K-Femetasomatism(StageI):K-feldspar+magnetite+apatite+amphibole+biotite鉀-鐵交代蝕變（StageI）：鉀長石+磁鐵礦+磷灰石+角閃石+黑云母Chloritebrecciation(StageII):chloritebrecciaedK-Fealteredclasts(StageI)

綠泥石化角礫（StageII）：綠泥石基質(zhì)包裹早期鉀-鐵蝕變角礫Mantoverde:Mineralization（礦化特征）IOCG:MantoverdeBenavides,2006hematite+sulfidescementedbreccias(supergene)表生礦化赤鐵礦角礫350350μHypogenemineralization:hematite+chalcopyriteafterpyriteandmagnetite原生銅礦化：赤鐵礦+黃銅礦產(chǎn)于黃鐵礦及磁鐵礦之后Mantoverde:SulfurIsotope（硫同位素）IOCG:MantoverdeBenavides,2006Theδ34Svaluesofthehydrothermalfluidsincreaseddramaticallyfromearlytolateparageneticstages.流體

δ34S值從早期到晚期有很大提高，礦化階段為最高值，達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（磁鐵礦與赤鐵礦代表不同流體）Mantoverde:FluidEvolution（流體演化）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（流體演化）δ18OfluidδDfluidFluidmixinginorestageBenavides,2006IOCG:MantoverdeMantoverde:OreGeneticModel（成礦模式）Mantoverdeca.130MaBenavides,2006MantoverdeIOCG:MantoverdeMantoverde:OreGeneticModel（成礦模式）ca.117MaBenavides,2006CentralAndeanIOCGOreGeneticModel-中安第斯山IOCG成礦模式IOCG:CentralAndesChen,2008ExplorationofIOCGDeposits（IOCG礦床地質(zhì)勘探）IOCG:ExplorationDiscoveryhistoriesofmajordepositsarealwaysimportantguidelinesforfutureexploration

重視主要礦床的發(fā)現(xiàn)過程對該類型礦床的進一步勘探大有幫助ExplorationGuidelines:Regionalgeologicalfeatures（勘探應(yīng)用：區(qū)域地質(zhì)特征）IOCG:ExplorationAlltemporallyassociatedwithregionalmagmatism,somespatiallyclosed

與同時期區(qū)域巖漿作用相關(guān)，部分空間關(guān)系緊密

Associatedwithregionalfaultsystem,orebodiescommonlycontrolledbyfaults(normalfaultsdominated)與區(qū)域斷裂緊密相關(guān)；礦體常由斷層控制（多為正斷層）

RegionalNa-Caalterationcommondeveloped普遍發(fā)育區(qū)域鈉-鈣蝕變

commonlylocatedontheboundaryofbasins(CentralAndes)常位于盆地邊緣（中安第斯山普遍）ExplorationGuidelines:StructureandIntrusions（勘探指示：斷層及巖體）IOCG:ExplorationOlympicDamGawlerCratonHiltabaintrusionsOlympicDamFracturesinferredfromgravitymapSkirrow,2006ExplorationGuidelines:StructureandIntrusions（勘探指示：斷層及巖體）IOCG:ExplorationWilliamsintrusionsCloncurryDistrictpmd*CRC,2005MajorIOCGdepositsareassociatedwithWilliamsgranitesandregionalstructures主要IOCG礦床與Williams花崗巖及區(qū)域斷裂關(guān)系密切Alterationzonation–vectortoorebody（蝕變分帶–礦體指向）IOCG:ExplorationWilliams,2009ErnestHenryKK(%)Cu>0.5wt%FeFe(%)PeripheralzoneNa-CaalterationadjacentzoneK-FealterationOrezoneCu-AumineralizationCommonbutnotalways:常見分帶但非絕對標準Distal遠帶Ore礦帶TextureZonation–vectortoorebody（礦化結(jié)構(gòu)分帶–礦體指向）IOCG:ExplorationMarketal.,2005Breccia(mineralization)礦化角礫巖體Veins脈狀礦化Alteredhostrocks蝕變圍巖Hostrocks圍巖Ore礦帶ErnestHenryTextureZonation–vectortoorebody（礦化結(jié)構(gòu)分帶–礦體指向）IOCG:ExplorationFairclough,2008OlympicDambrecciazonationHostrocksOreExplorationGuidelines:Geophysics（勘探應(yīng)用：地球物理方法-物探）IOCG:ExplorationSkirrow,2006GawlerCraton-OlympicDamapplicationTotalMagneticIntensity磁異常強度分布Gravity重力異常分布ExplorationGuidelines:Geophysics（勘探應(yīng)用：地球物理方法-物探）IOCG:ExplorationWilliams,2009OlympicDamDiscoveryFeaturesOlympicDamTotalMagneticIntensity奧林匹克壩地區(qū)磁異常強度分布However:Magneticanomalyhasadeeper(unknown)source磁異常來自深部未知區(qū)域Gravityanomalyiscausedbyhematiteintheorebody重力異常是由礦體中的赤鐵礦導致ExplorationGuidelines:Geophysics（勘探應(yīng)用：地球物理方法-物探）IOCG:ExplorationMagnetite-HematitemapinGawlerCratonSkirrow,2006OlympicDam1.5%“magnetite”

Includesallsusceptiblemineralsastheirmagnetiteequivalent1.5%磁鐵礦邊界線0.5%“haematite”

Includeshematite,

sulfides,gold,otherdenseminerals,andremanentmagnetisation0.5%赤鐵礦邊界線

3DinversionmapcombiningmagneticandgravitymapsExplorationGuidelines:Geophysics（勘探應(yīng)用：地球物理方法-物探）IOCG:ExplorationCloncurryDistrict-ErnestHenryapplicationTotalMagneticIntensity磁異常強度分布ErnestHenryErnestHenryCloncurrypmd*CRC,2005ExplorationGuidelines:Geochemistry（勘探應(yīng)用：地球化學方法-化探）IOCG:ExplorationHowever,neitherNa-norK-Fe-metasomatismcanbeusedasaccuratevectorforCu-Aumineralization–i.e.,canvectortobarrenmagnetitesystems但是，鈉-鈣蝕變或者鉀-鐵蝕變都不能準確定位礦體位置，因為他們可能指向不含礦的磁鐵礦體AtMantoverdedistrict,K-FealterationindexcanidentifyfertileIOCGmineralization,butalsomixwithbarrenmagnetitesystems在Mantoverde地區(qū)，鉀-鐵蝕變指數(shù)可以鑒定出IOCG礦化區(qū)，但同時也“鑒定”出不含礦的磁鐵礦體CerroNegro(249Mt@0.4%Cu0.15g/tAu)SantoDomingoSur(172Mt@0.57%Cu0.08g/tAu)Mantoverde(400Mt@0.52%Cu0.11g/tAu)PalmiraCarmenPirulaBenavidesetal.,2008ExplorationGuidelines:Geochemistry（勘探應(yīng)用：地球化學方法-化探）IOCG:ExplorationWholerockδ18Ovs.alterationindexatMantoverdeBenavidesetal.,2008Mantoverde地區(qū)結(jié)合全巖氧同位素與蝕變強度指導找礦ExplorationGuidelines:Geochemistry（勘探應(yīng)用：地球化學方法-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與礦化緊密相關(guān)并且記錄了流體混合過程，可以用地球化學手段探測ExplorationGuidelines:Geochemistry（勘探應(yīng)用：地球化學方法-化探）IOCG:ExplorationHowtotracetheexternalfluidsatMantoverdeK-enrichment,Na-depletionK-depletionBenavidesetal.,2008ExplorationGuidelines:Geochemistry（勘探應(yīng)用：地球化學方法-化探）IOCG:ExplorationHowtotracetheexternalfluidsatMantoverdeδD,‰(Fluid)CompositionalrangeforfluidinequilibriumwithChl-Ser-Hem-Calatca.350?C.δ18O,‰(Fluid)IsotopiccompositionoffluidinequilibriumwithHematiteatca.200-250?C.STAGEIIISTAGEIISTAGEICompositionalrangeforFluidinequilibriumwithMt(500?C)Benavidesetal.,2008IOCGFutureStudies:今后研究重點IOCG:FutureOreDepositModeling（成礦模式構(gòu)建）:stillalooseclanwithaconfuseddefinition,needmorecasestudiesandre-constructionofpresentmodels（定義及礦床系列不明確，需要更多的典型實例研究，已有的成礦模式需要更新；中國具有IOCG潛力，應(yīng)該在該領(lǐng)域做出貢獻，目前缺乏高水平的典例研究）Ore-formingFluidsEvolution（成礦流體演化）：

needdetailedparagenesisstudiesandmultiplemethodstotrackore-formingfluids（需要詳細的成礦過程研究