单个流体包裹体LA_ICP_MS成分分析及在矿床学中的应用

201012December,2010MINERALDEPOSITS296Vol.29No.6:02587106(2010)06101712LAICPMS李晓春,范宏瑞**,胡芳芳,杨奎锋(,100029),,LAICPMSLAICPMS,LAICPMS,LAICPMS;LAICPMS;;;:P599:AAnanalysisoftheindividualfluidinclusionbyLAICPMSanditsapplicationtooredepositsLIXiaoChun,FANHongRui,HUFangFangandYANGKuiFeng(KeyLaboratoryofMineralResources,InstituteofGeologyandGeophysics,ChineseAcademyofSciences,Beijing100029,China)AbstractFluids,whichplayasignificantroleinthehydrothermaloreformingsystem,aredirectlyrepresentedbyfluidinclusionstrappedduringmineralgrowth.Fluidinclusionssupplykeysourceinformationontheoreformingprocess,andLAICPMSisapowerfultoolforquantitativemeasurementofmultielementconcentrationsintheindividualfluidinclusion.Thispaperbrieflydescribestheprocess,characteristicsandstrategiesofthisanalyticaltechniqueaswellassomecriteriaforselectionoffluidinclusionssuitableforLAICPMSanalysis.Theapplicationofthistechniquetooredepositisalsodiscussedinsuchaspectsasthepropertiesoforeformingfluids,theoriginoforeformingfluids,theevolutionprocessoforeformingfluids,thefactorsinducingoremetalsprecipitation,thegenesisoforemetals,thepartitioningofdifferentelementsduringdifferentphaseseparationprocesses,andthesupplyofdatafororeformingprocesssimulation.AshortoutlookisgivenconcerningthepotentialfutureofindividualfluidinclusionanalysisbyLAICPMS.Keywords:geochemistry,LAICPMS,individualfluidinclusion,oredeposit,application(4062501040702016)(2006CB403503),,1986,,Email:[e-mail]**,,1963,,Email:[e-mail]20100628;20100817(LAICPMS)(,2001),,(ng/g)(Shepherdetal.,1995;Gntheretal.,1998;Heinrichetal.,2003),(,2004)LAICPMS,,1LAICPMS,(LA)(ICPMS),;,,,Jeffries(1998)Graupner(2005)213nm266nm,Ar,HeHe+Ar,,(Gntheretal.,1999)ICPMS,,(Hattendorfetal.,2000)He(Egginsetal.,1998),,(Gntheretal.,1998)1a~c:;,(),,;(),ICPMSLAICPMS(NIST),Na,:Cx,incl/CNa,incl=(Cx,std!INa,std!Ix,incl)/(CNa,std!Ix,std!INa,incl)CIxinclstd,Na,,:NaCl=NaCl-05!∀XClnNaCl(NaClequiv)(Heinrichetal.,1992),NaCl,NaClNa1(Gntheretal.,1998)Fig.1Schematicillustrationoflaserstepwiseablationprocessforfluidinclusion(afterGntheretal.,1998)10182010,4(Thomas,2008):#5~80m,20~50m,;∃,;%20m,40m,;&,,22.1LAICPMS,Wilkinson(2009)(Ireland)NorthernArkansas,,2;(2),2,;,,2,Su(2009)LAICPMS,w(Au)38!10-6~57!10-6,FeCuPbZn,,2(Ireland)NorthernArkansas(PbZnPbZn)(Wilkinsonetal.,2009)Fig.2Concentrationsoforeformingmetalsinquartzhostedandsphaleritehostedfluidinclusions(contentsofPbandZninsphaleritehostedfluidinclusionsaremuchhigherthanthoseinfluidinclusionshostedbyquartz)(afterWilkinsonetal.,2009)1019296:LAICPMSFe,Fe,Fe?,FeFe,,2,LAICPMS,2.2,,,,,;,,,LAICPMS,2Stoffell(2008)LAICPMSTriStateNorthernArkansasMVTClBr,/ClBr,2,ClBrLAICPMS,ClBr(3),,BrBr,Samson(2008)LAICPMSElMochito,/,,LAICPMS(),,Ca,3TriStateNorthernArkansasClBr(Stoffelletal.,2008)Fig.3ClBrNasystematicofmeasuredinclusionfluidcompositionsfromtheTriStateandNorthernArkansasdistricts(theircontentsareontheseawaterevaporationtrajectory)(modifiedafterStoffelletal.,2008)10202010,,,/,CaCa,,LAICPMS,2.3,,,,LAICPMSPudack(2009)NevadosdeFamatinaCuMoAuCuAu,(CL),9,,,(4),25km,CuMoAu;,,,LV,CuAu;,,,,pH4NevadosdeFamatinaCuMoAuCuAu(Pudacketal.,2009)Fig.4SchematicillustrationoforeformingprocessandfluidevolutionpathsfromporphyryCuMoAutoepithermalCuAuatNevadosdeFamatina(afterPudacketal.,2009)1021296:LAICPMS,CuAu,CuAuLAICPMS,2.4,,pHEh,LAICPMS,5YanleeLoad(Audtatetal.,1998)Fig.5Schematicillustrationfortheevolutionoftemperature,pressureandchemicalcompositionoforeformingfluids(afterAudtatetal.,1998)Audtat(1998)YanleeLoad,29,,LAICPMS(5),21KMnZnCsRb,21NaCl,,2023,Sn,,;2426B,,21,,1318,,Landtwing(2005)LAICPMSBinghamCu,425~350∋,Cu2,,Cu(6),400∋,,,,Cu,,Cu,Cu,LAICPMS,,2.5(),,102220106(420~350∋)BinghamCu,,(Landtwingetal.,2005)Fig.6Inanarrowtemperaturerange(420~350∋),thecontentofCuinfluidinclusiondecreasessharplyalongwiththedeclineofhomogenizationtemperature;moreover,thecontentofCufollowsacorrelationtrendparalleltothetemperaturesolubilitycurve.ThesefactsindicatethatfluidcoolingtendstobetheinducingfactorofCu(sprecipitation(modifiedafterLandtwingetal.,2005)7GrasbergAlumbreraCuAuCuAu(Alumbrera,)(Ulrichetal.,1999)Fig.7TheAu/CuratioofprimaryhightemperaturebrinesisidenticaltothebulkAu/CuratioinGrasbergandAlumbreracoppergoldorebodies(SomeCu/AuinbrineinclusionsarelowerthanthoseinorebodiesinAlumbrera.ThisisinterpretedtobeduetopreferentialpartitioningofCuintothevaporphase,ortopartialprecipitationasaCuFesulfide)(AfterUlrichetal.,1999),LAICPMS,Ulrich(1999)LAICPMSGrasbergAlumbrera2,1023296:LAICPMS(/),LAICPMSCuAu,2Grasberg,Au/CuAu/Cu(7)Alumbrera,2:Au/CuAu/Cu,Au/Cu;Au,Cu,,Au/Cu,,Au/CuAu/Cu2AuCu,22.6,,LV,,LAICPMS/,,,Audtat(2000a)LAICPMSMole,,RbKCs,MnAsBClWLiPbBi,Audtat(1998;2000a;2000b)Heinrich(1999)/,Heinrich(1999)8(a)(b)CuS1)2;S/NaCu/Na(c)(Seoetal.,2009)Fig.8MoralratioofCuandSisapproximately1)2inbothvaporinclusions(a)andbrineinclusions(b);(c)S/Navs.Cu/Na(afterSeoetal.,2009)Heinrich(1999)LAICPMS13,,NaKFe10242010MnZnRbCsAgSnPbTl;CuAsAu,Cl,SSeo(2009)LAICPMS11,CuAsAuS(8),CuS1)1(1)2,8a8b),S/NaCu/Na1)1(8c),CuSNaKFeCu,CuS1)2(HSCuSH2HSCuSO2HSCuSH-