|
|||||
|
|
| 北天山温泉群的地质特征、时代和构造意义 | |
| 引用本文： | 李孔森,王博,舒良树,王飞,刘洪升.北天山温泉群的地质特征、时代和构造意义[J].高校地质学报,2013,19(3):491-503. |
| 作者姓名： | 李孔森 王博 舒良树 王飞 刘洪升 |
| 作者单位： | 南京大学 地球科学与工程学院，内生金属矿床成矿机制研究国家重点实验室（南京大学），南京 210093 |
| 基金项目： | 国家自然科学基金(40802043;41172197)；国家重点基础研究发展计划(2007013411301)；全国优秀博士论文作者专项基金 |
| 摘 要： | 北天山温泉群长期以来被认为是古元古代的变质岩。最新的野外调查和锆石SHRIMP U-Pb 测年结果表明，温泉群可 以划分为三个岩石构造单元：（1）前早新元古代变质火山岩和变质沉积岩，主要包括斜长角闪岩、云母片岩、石英片岩、 黑云母片麻岩、大理岩等；（2）早新元古代混合岩和正片麻岩；（3）早古生代未变质变形的辉长岩和闪长岩。上述三种岩 石组合类型均被后期二云母花岗岩（脉）所侵入。温泉县以南的混合岩和花岗片麻岩中锆石的SHRIMP U-Pb 年龄分别为 926±12 Ma 和907±11 Ma，与天山地区出露的新元古代花岗岩类的时代基本一致。结合前人对花岗片麻岩Nd 同位素组成 的研究，花岗片麻岩应为古老地壳物质部分熔融的产物，而同期的混合岩化作用则是新元古代地壳加厚和部分熔融的直接 地质证据。辉长岩和闪长岩侵入到温泉群花岗片麻岩和斜长角闪岩中，其中闪长岩的锆石SHRIMP U-Pb 年龄为452±7 Ma， 并含有1.1 Ga 和1.4 Ga 的继承锆石。根据前人的研究成果，本区早古生代辉长岩和闪长岩具有岛弧岩浆岩的地球化学特征， 可能与准噶尔-巴尔喀什洋的俯冲作用有关，这一俯冲增生作用最终导致伊犁北部与哈萨克斯坦陆块在志留纪拼贴造山， 并使温泉群前寒武纪变质岩与侵入岩发生变质变形作用。 |
| 关 键 词： | 北天山 温泉群 锆石SHRIMP U-Pb年代学 新元古代 早古生代 |
Geological Features, Ages, and Tectonic Implications of the Wenquan Group in NW Chinese Tianshan |
|
| LI Kongsen , WANG Bo , SHU Liangshu , WANG Fei , LIU Hongsheng.Geological Features, Ages, and Tectonic Implications of the Wenquan Group in NW Chinese Tianshan[J].Geological Journal of China Universities,2013,19(3):491-503. | |
| Authors: | LI Kongsen WANG Bo SHU Liangshu WANG Fei LIU Hongsheng |
| Institution: | LI Kongsen;WANG Bo;SHU Liangshu;WANG Fei;LIU Hongsheng;State Key Laboratory for Mineral Deposits Research, Nanjing University, School of Earth Sciences and Engineering; |
| Abstract: | The metamorphic rocks of the Wenquan Group in the Northern Chinese Tianshan have been regarded as Paleoproterozoic in age. According to our field observations and zircon SHRIMP U-Pb dating, the Wenquan Group can be subdivided into three lithotectonic units: (1) pre-Early Neoproterozoic meta-volcanic and meta-sedimentary rocks, including amphibolite, micaschist, quartz schist, biotite gneiss and marble; (2) Early Neoproterozoic migmatite and orthogneiss; and (3) undeformed Early Paleozoic gabbro and diorite. All these three units were intruded by two-mica granite or dykes. Migmatite and granitic gneiss collected from the south of Wenquan City yielded zircon SHRIMP U-Pb ages of 926±12 Ma and 907±11 Ma, respectively. These ages are close to those of Neoproterozoic granitoids occurring in the Chinese Tianshan. Previous results of a Nd isotopic study on orthogneiss indicate an origin of partial melting of continental crust, and the occurrences of synchronous migmatite support a thickening and partial melting of continental crust. Gabbro and diorite intruded in the granitc gneiss and amphibolite of the Wenquan Group. A diorite yields a zircon SHRIMP U-Pb age of 452±7 Ma, and contains inherited zircons with older ages of 1.1 Ga and 1.4 Ga. According to the previous studies, the gabbro and diorite have geochemical features of arc-related magmatism, the early Paleozoic arc-type magmatic rocks of the study area were likely formed during subduction of the Junggar-Balkhash Oceanic lithosphere, and the subsequent accretion between the Northern Yili block and the Kazakhstan continent that induced the metamorphism and deformation of the Precambrian metamorphic and magmatic rocks of the Wenquan Group. |
| Keywords: | North Chinese Tianshan Wenquan Group zircon SHRIMP U-Pb ages Neoproterozoic Early Paleozoic |
| 本文献已被 CNKI 万方数据 等数据库收录！ | |
| 点击此处可从《高校地质学报》浏览原始摘要信息 | |
| 点击此处可从《高校地质学报》下载免费的PDF全文 | |