东昆仑造山带东段元古界小庙岩组的锆石U-Pb年龄  

Zircon U-Pb Age of Xiaomiao Formation of Proterozoic in the Eastern Section of the East Kunlun Orogenic Belt

作　　者：陈有炘[1] 裴先治[1] 李瑞保[1] 刘战庆[1] 李佐臣[1] 张晓飞[1] 陈国超[1] 刘智刚[1] 丁仨平 郭俊锋[1] 

机构地区：[1]西部矿产资源与地质工程教育部重点实验室长安大学地球科学与资源学院,陕西西安710054

出　　处：《现代地质》2011年第3期510-521,共12页Geoscience

基　　金：国家自然科学基金项目(40972136;40572121);中央高校基本科研业务费专项资金项目(CHD2009JC070;CHD2009JC053;CHD2009JC046);青海省国土资源厅-中国铝业公司公益性区域地质矿产调查基金项目(中铝基金200801)

摘　　要：通过对东昆仑造山带东段香日德南部可可沙地区前寒武纪变质基底小庙岩组的野外地质调查,运用岩石学研究和LA-ICP-MS锆石U-Pb测年方法,探讨小庙岩组的形成时代。结果表明：小庙岩组主要为一套石英质变质岩系,可归纳为4种岩性组合,即黑云石英片岩-石英岩组合、片麻岩-片岩组合、角闪片岩-黑云石英片岩组合和石英岩-大理岩组合。原岩组合可能为一套火山-沉积建造,属于浅海陆缘沉积,变质条件为中压低角闪岩相。锆石U-Pb年代学表明,小庙岩组物源区存在1 600~2 729 M a的构造-热事件,其主体形成于1 683~1 554 M a,时代归属中元古代。After detailed means of field geological survey,petrologic study and LA-ICP-MS zircon U-Pb chronology method about Xiaomiao Formation,the age of the metamorphic basement formed in Pre-Cambrian in Kekesha area of Xiangride Town in the eastern section of the East Kunlun orogenic belt is discussed.The results show that Xiaomiao Formation is mainly a suite of quartz-consisted metamorphic rocks,which can be categorized into 4 classes,such as rock assemblages of biotite quartz schist-quartzite,gneiss-schist,hornblende schist-biotite quartz schist and quartzite-marble.These characteristics reveal that the original rock assemblage of the rocks may be a suite of volcano-sedimentary formation,which belongs to sedimentary system from shallow sea to continental margin in environment and low-amphibolite facies of middle pressure in metamorphic condition.Furthermore,the zircon U-Pb chronology indicates that there were geotectonic-thermal events in 1,600-2,729 Ma in source area of Xiaomiao Formation,most ages of which are distributed in 1,683-1,554 Ma of the Middle Proterozoic in geological time.

关 键 词：LA-ICP-MS锆石U-PB定年 岩石组合 小庙岩组 中元古代 东昆仑造山带 

分 类 号：P588.3[天文地球—岩石学] P534.3[天文地球—地质学]