准噶尔北部科克森套变质岩岩石地球化学特征、锆石U-Pb年龄及地质意义  

Rock Geochemistry Characteristics,Zircon U-Pb Ages and Their Geological Significance of the Coxentao Metamorphic Rocks in Northern Junggar

作　　者：滕宇翔 朱彦菲 薛晓峰 Teng Yuxiang;Zhu Yanfei;Xue Xiaofeng(Xinjiang Geological Survey Institute,Urumqi,Xinjiang,830000,China)

机构地区：[1]新疆维吾尔自治区地质调查院,新疆乌鲁木齐830000

出　　处：《新疆地质》2023年第3期338-346,共9页Xinjiang Geology

基　　金：第二次青藏高原综合科学考察研究项目(2019QZKK0806);新疆地勘基金吉木乃县恰勒什海一带1∶5万四幅区调项目(A16-1-LQ07);天山-阿尔泰增生造山带深部矿产潜力评价及编图(2018YFC0604001-04);新疆维吾尔自治区系列地质图件数据处理与洋板块地质研究项目(D1913)联合资助。

摘　　要：新疆西准噶尔北部科克森套蛇绿岩由蛇纹岩、橄辉岩、辉橄岩、辉长岩、辉石岩、玄武岩、硅质岩、含放射虫硅质板岩及基质组成,本文主要对科克森套基质(变质岩)进行研究。变质岩岩石化学特征表现为富Al_(2)O_(3)、贫K_(2)O,P_(2)O_(5),TiO_(2)的特点,稀土元素特征与岛弧玄武岩相似。微量元素表现为高Rb,Ba,Th,La,Ce,Nd,Hf,低K,Ta,Nb,Sr,P,Ti特征。变质岩中获得锆石年龄(365±1.8)Ma(晚泥盆世),为就位年代。从构造环境上,变质岩显示岛弧、同碰撞特征,与科克森套岛弧消减带扩张环境一致,因此科克森套蛇绿混杂岩形成早于晚泥盆世。The Coxentao ophiolite in the northern part of Western Junggar,Xinjiang,is composed of serpentine,peridotite,pyroxene,gabbro,pyroxenite,basalt,siliceous rock,radiolarian siliceous slate and matrix,in this paper,we mainly study the corksonite matrix(metamorphic rock).The geochemical characteristics of the metamorphic rocks are rich in Al_(2)O_(3),poor in K_(2)O,P_(2)O_(5) and TiO_(2),and the REE characteristics are similar to those of island arc basalts.High Rb,Ba,Th,La,Ce,Nd,Hf,and low K,Ta,Nb,Sr,P,and Ti were found in the micronutrient.The zircon age of the metamorphic rocks is 365±1.8 Ma(Late Devonian),indicating the age of emplacement.In terms of tectonic setting,the metamorphic rocks show the characteristics of island arc+co-collision,which is consistent with the spreading environment of the Coxentao Island arc subduction zone.

关 键 词：科克森套 变质岩 岩石化学 锆石U-PB测年 

分 类 号：P588.3[天文地球—岩石学] P59[天文地球—地质学]