摘要
东天山地区古生代的构造格局一直是地质界争议的问题之一。本文对阿其克库都克断裂南侧花岗岩和花岗闪长岩2个岩体进行锆石SHRIMPU-Pb定年,分别获得318Ma±5Ma和350Ma±7Ma的206Pb/238U表面年龄,综合分析岩体结构及锆石的矿物学特征,将上述2个年龄分别解释为所研究的花岗岩和花岗闪长岩的侵位年龄。通过对已有资料的综合研究,得出如下结论:①中天山地区在古生代期间的构造背景为类似安第斯型的活动陆缘或岛弧链,其形成与南天山洋盆岩石圈板块向北的俯冲作用有关;②花岗闪长岩锆石中还保留有继承锆石的信息,表明研究区存在老于503Ma±9Ma的基底物质;③研究区内沿阿其克库都克断裂右行走滑变形事件的下限时间是350Ma±7Ma,很可能发生在石炭纪以后。
The tectonic framework of the East Tianshan has long been one of controversial issues in the geological community. SHRIMP U-Pb dating of zircons from the granite and granodiorite plutons at the south side of the Aqqikkuduk fault yields apparent ^206Pb/238U ages of 318±5 Ma and 350±7 Ma respectively. According to the characteristics of the granite and granodioritic plutons and related zircon CL images, these two ages are explained as the intrusion ages of the two plutons. Based on an integrated analysis of the available data, the authors get the following conclusions： ① the Paleozoic tectonic setring of the Central Tianshan was similar to the Andean active continental margins or island arc chain, whose formation is related to northward subduction of the lithospheric plate of the South Tianshan oceanic basin; ② the information of inherited zircons preserved in zircons of granodiorite indicates that there exists basement material which is older than 503±9 Ma in the study area; and ③ the dextral strike-slip deformation along the Aqqikkuduk fault took place later than 350±7 Ma, probably after the Carboniferous.
出处
《地质通报》
CAS
CSCD
北大核心
2006年第8期945-952,共8页
Geological Bulletin of China
基金
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<中亚型造山与成矿综合研究>(编号2001CB409810)部分成果。
