| 西藏安多地区早古生代及中生代造山记录:来自安多微陆块-南羌塘锆石U-Pb年代学及Hf同位素研究 |
| |
| 引用本文： | 贠晓瑞,蔡志慧,何碧竹,郑孟林,焦存礼,彭阳,刘若涵.西藏安多地区早古生代及中生代造山记录:来自安多微陆块-南羌塘锆石U-Pb年代学及Hf同位素研究[J].岩石学报,2019,35(6):1673-1692. |
| |
| 作者姓名： | 贠晓瑞 蔡志慧 何碧竹 郑孟林 焦存礼 彭阳 刘若涵 |
| |
| 作者单位： | 自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037;中国地质大学, 北京 10008,自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037,自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037,中国石油新疆油田分公司勘探开发研究院, 克拉玛依 834000,中国石化勘探开发研究院, 北京 100083,自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037,自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037 |
| |
| 基金项目： | 本文受国家自然科学基金项目（41872121、41630207、91755101、41302166）、中国地质科学院基本科研业务项目（A1903、JYYWF20180903、JYYWF20182103）和中国地质调查局项目（DD20160022、DD20160169、12120115026901、DD20190006）联合资助. |
| |
| 摘 要： | 安多地区位于青藏高原腹地,为拉萨地体、羌塘地体及安多微陆块的结合部位,是研究拉萨地体、羌塘地体起源以及特提斯造山过程的关键位置。我们对采自安多地区的前中生代基底岩石及侏罗系沉积岩样品进行了岩石学、锆石U-Pb年代学及Hf同位素研究。研究结果表明:安多花岗片麻岩中锆石同时记录了510～505Ma岩浆年龄以及187Ma变质年龄;187Ma的变质锆石与510～505Ma的岩浆锆石具有相似的Hf同位素模式年龄(1.7～1.5Ga),表明寒武纪花岗岩主要来源于古老地壳重熔。碎屑锆石年代学分析结果揭示了安多微陆块石英岩具有498～484Ma、800～1000Ma和1800～1950Ma的年龄峰值,与南羌塘地体及特提斯喜马拉雅碎屑锆石年龄分布特征相似,表明其在早古生代时位于冈瓦纳大陆北部印度陆块边缘。南羌塘坳陷东南部中侏罗世砂岩及钙质砂岩碎屑锆石年代学分析结果显示其具有182～171Ma、450～600Ma、800～1000Ma、1800～1950Ma及2400～2600Ma的年龄峰值,这种年龄分布特征与安多微陆块及南羌塘地体相似,而与拉萨地体不同,说明南羌塘坳陷东南部下-中侏罗统物源主要来自安多微陆块及南羌塘地体,在早-中侏罗世时安多微陆块与南羌塘地体已经发生了碰撞造山。
|
| 关 键 词： | 安多 U-Pb定年 Hf同位素 早古生代造山 侏罗纪造山 |
| 收稿时间： | 2019/1/8 0:00:00 |
| 修稿时间： | 2019/4/12 0:00:00 |
Early Paleozoic and Mesozoic orogenic records in Amdo region, Tibet: Zircon U-Pb geochronology and Hf isotopic compositions from the Amdo micro-continent and South Qiangtang terrane |
| |
| YUN XiaoRui,CAI ZhiHui,HE BiZhu,ZHENG MengLin,JIAO CunLi,PENG Yang and LIU RuoHan.Early Paleozoic and Mesozoic orogenic records in Amdo region, Tibet: Zircon U-Pb geochronology and Hf isotopic compositions from the Amdo micro-continent and South Qiangtang terrane[J].Acta Petrologica Sinica,2019,35(6):1673-1692. |
| |
| Authors: | YUN XiaoRui CAI ZhiHui HE BiZhu ZHENG MengLin JIAO CunLi PENG Yang and LIU RuoHan |
| |
| Institution: | MNR Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China;China University of Geosciences, Beijing 10008,MNR Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China,MNR Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China,Petroleum Exploration and Development Institute, Xinjiang Oilfield Company, Petrochina, Karamay 834000, China,SINOPEC Petroleum Exploration and Production Research Institute, Beijing 100083, China,MNR Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China and MNR Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China |
| |
| Abstract: | Amdo region, located in the hinterland of the Qinghai-Tibet Plateau, is the junction of Lhasa, Qiangtang terranes and Amdo micro-continent. It is the key position to study the origins of Qiangtang and Lhasa terranes and Tethyan orogenic process. Here we report petrology, zircon U-Pb chronology and Hf isotopic data of Pre-Mesozoic basement and Jurassic sedimentary rocks from the Amdo region. The results show that the granitic gneiss simultaneously recorded the Early Paleozoic magmatic event of 510~505Ma and Early Jurassic metamorphic event of 187Ma. The metamorphic zircons with 187Ma age have a similar Hf isotopic model age (1.7~1.5Ga) with the magma crystalline zircons of 510~505Ma, indicating the Cambrian granite hosting the crystallized zircons was the products of old crust melting. The chronological analysis of detrital zircons of the quartzite in the Amdo micro-continent shows age peaks of 498~484Ma, 800~1000Ma and 1800~1950Ma. The age distribution in the Amdo micro-continent is similar to that in South Qiangtang and Tethyan Himalayas terranes, indicating that they were located at the margin of the Indian continent in the northern part of Gondwana supercontinent during the Early Paleozoic. Jurassic sandstones and calcareous sandstones in the southeastern part of South Qiangtang depression recorded the age peaks of 182~171Ma, 450~600Ma, 800~1000Ma, 1800~1950Ma and 2400~2600Ma. The age distribution is similar to that in the Amdo micro-continent and South Qiangtang, but different from which in Lhasa terrane, indicating that the deposits in the southeastern South Qiangtang depression provenance from Amdo micro-continent and South Qiangtang terrane. At early-middle Jurassic, the Amdo micro-continent had collided with the South Qiangtang terrane. |
| |
| Keywords: | Amdo U-Pb dating Hf isotope Early Paleozoic orogeny Jurassic orogeny |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《岩石学报》浏览原始摘要信息 |
| 点击此处可从《岩石学报》下载免费的PDF全文 |
|
