华北与西伯利亚板块的对接过程:来自西拉木伦缝合带变形花岗岩锆石LA-ICP-MS U-Pb年龄证据  

Collision Processes of North China and Siberian Plates:Evidence from LA-ICP-MS Zircon U-Pb Age on Deformed Granite in Xar Moron Suture Zone

作　　者：李益龙[1,2] 周汉文[1,2] 钟增球[1,2] 张雄华[1] 廖群安[1] 葛梦春[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2009年第6期931-938,共8页Earth Science-Journal of China University of Geosciences

基　　金：国家重点基础研究发展计划项目(No.2007CB411307);中国地质调查局项目(No.1212010510507)

摘　　要：房框子沟花岗质片麻岩NEE向展布于内蒙古林西县双井镇的房框子沟村一带,是一套侵入到双井片岩中的变质变形侵入体,其边缘和中央分别为云染状和均质的花岗质片麻岩.利用LA-ICP-MS锆石U-Pb原位定年方法对采自该侵入体边缘和中央的样品进行了定年,结果表明,岩浆在271.9±1.6Ma开始侵位于双井片岩中,在接触带上多发生混合岩化,造成岩体边缘呈云染状,在264.8±1.8Ma岩体主体侵位,之后由于西伯利亚板块与华北板块的持续碰撞缝合,岩体在应力作用下变形变质形成了今天看到的房框子沟花岗质片麻岩的面貌,到231±2Ma碰撞基本结束,西伯利亚板块与华北板块最终拼合.The Fangkuangzigou granitic gneisses, extending with NEE trend along Fangkuangzi village in Linra county, Inner- Mongolia province, are deformed and metamorphosed granites which intruded into the Shuangjing schists. The gneisses are nebulitic and homogeneous separately in its edge and center. The LA-ICP-MS zircon U-Pb dating method was applied to determine the ages of gneisses both from the edge and center. It is indicated that the magma emplacement initiated at about 271.9±1.6 Ma ago and intruded into Shuangjing schists, then migmatization and nebulitic structure were induced into the contact zones. The pluton was formed dominantly at 264. 8± 1.8 Ma ago. The pluton was deformed and metamorphosed into granitic gneiss by the collision betweenthe Siberian and North China plates. The collision was ended until 231±2 Ma ago, then the Siberian and North China plates were finally converged.

关 键 词：花岗质片麻岩 锆石 LA-ICP-MS U-Pb定年 地质年代 双井 内蒙古 

分 类 号：P597[天文地球—地球化学]