北秦岭西段胡店片麻状二长花岗岩LA-ICP-MS锆石U-Pb测年及其地质意义  

LA-ICPMS zircon U-Pb dating of the Hudian gneissic monzogranitein the western segment of the North Qinling and its geological significance

作　　者：王洪亮[1] 何世平[1] 陈隽璐[1] 徐学义[1] 孙勇[2] 第五春荣[2] 李海平[2] 

机构地区：[1]西安地质矿产研究所,陕西西安710054 [2]西北大学大陆动力学国家重点实验室,陕西西安710069

出　　处：《中国地质》2007年第1期17-25,共9页Geology in China

基　　金：西北地区重要成矿带基础地质综合研究项目(200313000028)

摘　　要：北秦岭西段陕西胡店片麻状细粒二长花岗岩中获得(1770±13)Ma的LA-ICP-MS单颗粒锆石微区U-Pb同位素年龄;岩石地球化学资料研究证明,该片麻状细粒二长花岗岩形成于板块边缘的俯冲-碰撞构造环境,岩浆源于部分熔融的中上地壳物质。该变形侵入体形成的地质构造背景及时代与太白岩基巩坚沟变形侵入体基本一致,代表了北秦岭造山带西段古元古代末、中元古代初期的一次强烈的构造岩浆事件。该事件与中国的吕梁运动时代大体相当,可能与Columbia超大陆的形成有一定的成因联系。这一新的资料,对研究北秦岭造山带元古宙大地构造格局、构造演化及中国大陆动力学具有重要意义。The Hudian deformed intrusion in the north of Baoji batholith consists of gneissic monzogranite. Zircons from the rock yielded a LA-ICPMS U-Pb age of 1770±13 Ma. Petrologic and geochemical study shows that the gneissic monzogranite formed in a subduction-collision environment on the plate margin and that the magma originated by partial melting of mid-upper crustal materials. The tectonic setting and age of this deformed intrusion are in the main consistent with those of the Gongjiangou deformed intrusion in the Taibai batholith, representing a strong tectono-magmatic event occurring in the western segment of the North Qinling orogenic belt in the terminal Paleoproterozoic and initial Mesoproterozoic. The event broadly corresponded to the L/iliang movement and might have certain genetic relation to the formation of the supercontinent Columbia. This new information has great significance for the study of the Proterozoic tectonic framework and tectonic evolution in the North Qinling orogenic belt and the dynamics of continental of China.

关 键 词：北秦岭造山带 胡店片麻状二长花岗岩 U—Pb同位素 吕梁运动 Columlbia超大陆 

分 类 号：P597[天文地球—地球化学]