新疆西准噶尔晚古生代侵入岩的年龄和构造意义：来自锆石LA-ICPMS定年的证据  

Ages and tectonic implication of Late Paleozoic plutons in the West Junggar,North Xinjiang: Evidence from LA-ICPMS zircon geochronology

作　　者：尹继元[1] 陈文[1] 袁超[2] 张运迎[2] 龙晓平 喻顺[1] 张彦[1] 李洁[1] 孙敬博[1] 

机构地区：[1]中国地质科学院地质研究所同位素热年代学实验室,大陆构造与动力学国家重点实验室,北京100037 [2]中国科学院广州地球化学研究所同位素地球化学国家重点实验室,广东广州510640

出　　处：《地球化学》2013年第5期414-429,共16页Geochimica

基　　金：国家自然科学基金(41203026,41073031,41273012);中国地质科学院地质研究所基本科研业务费项目(J1209);公益性行业专项经费(201211074-05);地质矿产调查评价专项(12120113015600)

摘　　要：晚古生代以来，西准噶尔地区出露有一系列的侵入岩，成为了解该地区地壳生长的重要窗口。通过对西准噶尔北部7个晚古生代侵入岩体的LA-ICPMS锆石U-Pb年龄的研究，并结合前人的锆石u-Pb定年结果，将西准噶尔晚古生代的岩浆活动分为两期，一期为早石炭世（346～321Ma），另一期为晚石炭．早二叠世（316-281Ma）。早石炭世的侵入岩主要由I型花岗岩组成，仅出露于西准噶尔北部的扎尔玛-萨吾尔火山弧上。这些侵入岩的产生可能与额尔齐斯．斋桑洋的南向俯冲有关。而晚石炭-早二叠世的侵入岩在西准噶尔南部（316-287Ma）和北部（303～283Ma）都广泛分布。这些侵入岩主要由A型花岗岩、紫苏花岗岩、埃达克岩和富镁闪长岩等特殊岩石组成，它们反映了一个高温和张性的背景。洋脊俯冲伴随板片窗的形成可能是西准噶尔晚石炭-早二叠世侵入岩产生的重要机制。Voluminous Late Paleozoic plutons distributed throughout the West Junggar region provide critical information for the Phanerozoic crustal growth. On the basis of new zircon U-Pb dating on seven plutons in the Northern West Junggar region, in association with the previous zircon U-Pb ages, the plutons can be divided into two groups： Early Carboniferous （ca. 346 to 321 Ma）, Late Carboniferous-Early Permian （ca. 316 to 281 Ma）. The Early Carboniferous plutons mainly consist of 1-type granites and only occur in Zharma-Saur volcanic arc, and may be related to the southward subduction of the Irtysh-Zaysan Ocean. Late Carboniferous-Early Permian plutons are widely distributed in the northern and southern parts of the West Junggar region. The plutons composed of A-type granites, Charnockites, adakites, magnesian diorites, which indicate a high-temperature and extensional setting. All these suggest that ridge subduction and slab window formation are likely an important mechanism for the generation of the Late Carboniferous-Early Permian plutons in the West Junggar region.

关 键 词：侵入岩 LA-ICPMS 锆石U-PB定年 晚古生代 西准噶尔 

分 类 号：P597[天文地球—地球化学]