新疆东部哈尔里克山闪长岩锆石SHRIMP U-Pb定年及其地质意义  

Zircon SHRIMP U-Pb Age of a Dioritic Pluton in the Harlik Mountain,Eastern Xinjiang, and Its Tectonic Implication

作　　者：孙桂华[1] 李锦轶[1] 高立明 杨天南[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中非地质工程勘查设计研究院,北京100102

出　　处：《地质论评》2005年第4期463-469,共7页Geological Review

基　　金：本文为国家重要基础发展规划项目"中国西部中亚型造山与成矿"综合研究课题(编号2001CB409810)的成果。

摘　　要：新疆东部哈尔里克山出露大量闪长岩和花岗岩岩体。一般认为,该区晚古生代岩浆活动中,闪长岩形成比较早,花岗岩形成比较晚。对其中一个闪长岩中的锆石进行SHRIMP U-Pb定年,获得了316±3 Ma的206Pb/238U表面年龄。结合岩体及锆石的矿物学特征,该年龄被解释为代表了哈尔里克山晚古生代岩浆初始侵入活动的时间。通过与前人从博格达山和哈尔里克山获得的岩浆活动年代学资料的比较研究,得出的结论是博格达山与哈尔里克山晚古生代岩浆初始侵入活动的时间大体相同,都发生在该区地壳形成演化的后碰撞阶段;由此进一步推论哈尔里克山晚石炭世期间的构造背景与博格达山基本相同,为与康古尔塔格一带洋岩石圈板块向北俯冲有关的板缘伸展环境下的滞后弧后盆地或者是后碰撞伸展环境下的火山沉积盆地。Many dioritic and granitic plutons crop out in the Harlik Mountain, eastern Xinjiang, NW China. it is well known that the formation of diorite is earlier than that of granite in Late Paleozoic magmatism this area. SHRIMP U-Pb dating of zircons from the diorite yields an apparent ^206Pb/^238U age of 316±3 Ma. According to the characteristics of the dioritic plutons and related zircon CL images, this age is explained as the beginning time of the Late Paleozoic magmatism in the Harlik Mountain. Available chronological data allow a tentative conclusion that the Late Paleozoic magmatic intrusion in the Bogda and Harlik Mountains began in the Late Carboniferous and occurred in the post-collisional stage of the orogenic processes. It is further deduced that the Late Carboniferous tectonic setting of the Harlik Mountain is an extensional basin similar to that of the Bogda Mountain. But it is open to further investigation to study whether the basin was a lagged back-arc basin on the active continental margin or a post-collisional volcano-sedimentary basin.

关 键 词：新疆 哈尔里克山 闪长岩 锆石 地质意义 地质年代学 同位素年代学 

分 类 号：P597.3[天文地球—地球化学] P588.1[天文地球—地质学]