西昆仑库地蛇绿岩的二辉辉石岩和玄武岩锆石LA-ICP-MSU - 岩石学报.PDF
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10000569/2014/030(08)239301 ActaPetrologicaSinica 岩石学报
西昆仑库地蛇绿岩的二辉辉石岩和玄武岩锆石
LAICPMSUPb年龄及其意义
李天福 张建新
LITianFuandZHANGJianXin
大陆构造与动力学国家重点实验室,中国地质科学院地质研究所,北京 100037
StateKeyLaboratoryofContinentalTectonicsandDynamics,InstituteofGeology,ChineseAcademyofGeologicalSciences,Beijing100037,China
20140310收稿,20140514改回
LiTFandZhangJX2014ZirconLAICPMSUPbagesofwebsteriteandbasaltinKudiophioliteandtheimplication,
WestKunlunActaPetrologicaSinica,30(8):2393-2401
Abstract WestKunlunorogenissubdividedintonorthterreneandsouthterreneTheknownKudiophioliteinsouthterreneof
WestKunlunorogeniscomposedofultramaficbodyinBuziwanvalleyandextrusiverocksinYixiekevalleyfromthebottomupThere
hasbeenahotdebatingaboutageofKudiophioliteThisstudyhascollectedsamplesandobtainedzirconLAICPMSUPbagesof
49428±086Maand50030±80MarespectivelyforwebsteritefromBuziwanvalleyultramaficbodyanddoleritefromlowerpartof
YixiekevalleyextrusiverocksinKudiophioliteThesetwoagesareverysimilarandindicatethattheultramaficbodyandlowerpartof
theextrusiverocksarecomposingmembersofLateCambrianEarlyOrdovicianophiolite,ie,Kudiophiolitewastheresidueof
PrototethysOceanPreviousstudiesbyotherresearchersgotthevariousagedataforultramaficrocksandextrusiverocksThereasonof
largevarietyofageisthatdifferentauthorsuseddifferentdatingmethods(includingRadiolarian)ondifferentsamplescollectedat
differentlocalities(especiallyforextrusiverocksofupperunitoftheophiolit),nottosaymostofthedatingmethodsusedwerenot
fairlyreliableOurreliableinsitumethodage(50030±80Ma)ofdoleritefromlowermostpartofextrusivestratumisdifferentfrom
theanotherpreviouslypublishedinsituagedatum(alsoreliable)formassivebasalt,whichamplydemonstratethatthereasonofage
differenceisbecauseofdifferentlocalityofsamplingThus,theYishakeGroupshouldbedismemberedbecauseitmightbetectonicly
superimposedstratum
Keywords Age;Zircon;Websterite;Dolerite;Ophiolite;Kudi;WesternKunlun
摘 要 西昆仑造山带划分为北昆仑地体和南昆仑地体,关于西昆仑造山带中库地蛇绿岩的形成时代一直存在争议。本
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