东天山白石泉镁铁_超镁铁杂岩体的Nd_Sr_Os同位素成分及其对岩浆演化的意义

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1、1000-0569/2013/029(01)-0294-02ActaPetrologicaSinica岩石学报东天山白石泉镁铁-超镁铁杂岩体的Nd-Sr-Os同位素*成分及其对岩浆演化的意义1，2221陈斌贺敬博陈长健木合塔尔·扎日1，2221CHENBin，HEJingBo，CHENChangJianandMUHETAERZari1.新疆大学地质与勘查工程学院，乌鲁木齐8300462.北京大学地球与空间科学学院，北京1008711.SchoolofGeologyandExploration，Xinjia

2、ngUniversity，Urumqi830046，China2.SchoolofEarthandSpaceSciences，PekingUniversity，Beijing100871，China2012-09-08收稿，2012-11-30改回.ChenB，HeJB，ChenCJandMuhetaerZ.2013.Nd-Sr-OsisotopicdataoftheBaishiquanmafic-ultramaficcomplexfromEastTianshan，andimplicationsforpe

3、trogenesis.ActaPetrologicaSinica，29(1):294－302AbstractWereporttraceelementsandNd-Sr-OsisotopicdatafortheBaishiquanmafic-ultramaficcomplexthatoccursintheEastTianshanMountains(inthenorthernpartoftheMid-TianshanPrecambrianblock)andisaccompaniedbyCu-Nideposit

4、s，tounderstanditsmantlesourcecharacteristicsandprocessesofmantle-crustalinteraction.Geochemically，thecomplexischaracterizedbyenrichmentofLILEsanddepletionofHFSEs.Thewhole-rockSr-NdisotopiccompositionsoftheBaishiquancomplexvarysignificantly，8786with(Sr/Sr)

5、i=0.7032～0.7066andεNd(t)=5.6～－0.9，andtheNd-Srisotopicratiosarenegativelycorrelated.Thecomplex187188－12－12showsveryradiogenicOsisotopiccompositions，with(Os/Os)i=0.295～1.18andOs=80×10～29×10.Basedonthesedata，weconcludethat(1)theparentmagmaoftheBaishiquancomp

6、lexexperiencedsignificantcrustalcontaminationduringmagmaemplacement，asisrevealedbythenegativelycorrelatedandsignificantlyvariedNdandSrisotopiccompositionsandthehighlyradiogenicOsisotopiccompositions.ThisisdifferentfromapopularmodelthattheBaishiquancomplex

7、receivednocrustalcontaminationduringmagmaascent;(2)theparentmagmaoftheBaishiquancomplexoriginatedfromajuvenilelithosphericmantlethatwaspreviouslymetasomatizedbysubductionzonefluids/meltsinthePaleozoic.Thisrequiresreconsiderationofthenatureanddistributiono

8、ftheMid-TianshanPrecambrianblock.KeywordsNd-Sr-Osisotopes;Mafic-ultramaficrocks;Crustalcontamination;EastTianshan摘要本文报道东天山有铜镍硫化物矿化的白石泉镁铁-超镁铁杂岩体(分布在中天山地块北部)的微量元素和Nd-Sr-Os同位素成分，以探讨其地幔源区性质和壳幔相互作用过程。白石泉杂岩体的地球化学特征是富集大离子亲