首页 | 官方网站   微博 | 高级检索  
     

东昆仑没草沟蛇绿岩地球化学、LA-ICP-MS锆石U-Pb年龄及其地质意义
引用本文:王国良,刘建栋,杨雪松,刘荣,曹锦山,韩海臣,陈丽娟.东昆仑没草沟蛇绿岩地球化学、LA-ICP-MS锆石U-Pb年龄及其地质意义[J].地质通报,2019,38(4):573-591.
作者姓名:王国良  刘建栋  杨雪松  刘荣  曹锦山  韩海臣  陈丽娟
作者单位:青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012,青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012,青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012,青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012,青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012,青海省水文地质工程环境地质调查院, 青海 西宁 810008,青海省青藏高原北部地质过程与矿产资源重点实验室/青海省地质调查院, 青海 西宁 810012
基金项目:中国地质调查局项目《青海1:5万窑洞山地区两幅区调》(编号:1212011121192)和《青海省区域地质调查与片区总结》(编号:12120114079701)
摘    要:重点介绍了没草沟蛇绿岩岩石组合、地球化学特征等,并对该蛇绿岩构造背景进行了讨论。该蛇绿岩位于青海省格尔木市,构造上处于东昆仑复合造山带西段,岩石组合由变质基性玄武岩及少量辉绿岩、辉长岩、变质橄榄岩、辉橄岩等组成。岩石主量和微量元素特征显示该蛇绿岩与俯冲无关,属正常洋中脊型玄武岩。前人开展的地质调查表明,该蛇绿岩形成于晚奥陶世。通过对没草沟蛇绿岩中玄武岩和辉长岩进行LA-ICP-MS锆石U-Pb测年,分别获得了488.2±2.1Ma和500.8±2.2 Ma的年龄数据,确定该蛇绿岩形成时代为中寒武世—早奥陶世。该同位素年龄的获得填补了该地区蛇绿岩无时代依据的空白,同时反映古特斯洋在本区的残留。综合区域地质特征认为,没草沟蛇绿岩早期为初始洋盆环境,晚期有洋脊扩张中心环境的玄武岩形成。寒武纪早期是洋盆发育的全盛期,奥陶纪晚期洋壳发生消减,于晚志留世洋盆基本闭合,后期伴有绿片岩相变质作用。

关 键 词:没草沟蛇绿岩  地球化学  LA-ICP-MS锆石U-Pb年龄  构造意义
收稿时间:2018/5/18 0:00:00
修稿时间:2018/10/20 0:00:00

Geochemistry, LA-ICP-MS zircon U-Pb ages of the Meicaogou ophiolite in East Kunlun, and its geological significance
WANG Guoliang,LIU Jiandong,YANG Xuesong,LIU Rong,CAO Jinshan,HAN Haichen and CHEN Lijuan.Geochemistry, LA-ICP-MS zircon U-Pb ages of the Meicaogou ophiolite in East Kunlun, and its geological significance[J].Geologcal Bulletin OF China,2019,38(4):573-591.
Authors:WANG Guoliang  LIU Jiandong  YANG Xuesong  LIU Rong  CAO Jinshan  HAN Haichen and CHEN Lijuan
Affiliation:Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China,Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China,Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China,Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China,Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China,Qinghai Hydrogeology Engineering and Environment Geological Survey, Xining 810008, Qinghai, China and Qinghai Provincial Key Laboratory of Geological Processes and Mineral Resources of Northern Tibetan Plateau/Qinghai Geological Survey Institute, Xining 810012, Qinghai, China
Abstract:This paper mainly introduces the rock assemblage and geochemical characteristics of the Meicaogou ophiolite and attempts to discuss the tectonic background of the ophiolite which is located in Golmud City of Qinghai Province and lies in the western part of the East kunlun composite orogenic belt. The rock association is composed of metamorphic basic basalt and a small amount of diabase, gabbro, metamorphic peridotite and augite peridotite. The characteristics of main elements and trace elements indicate that the ophiolite is not related to subduction but belongs to N-MORB. In the past geological survey carried out by previous researchers, it was considered that the ophiolite was formed in Late Ordovician. The LA-ICP-MS zircon U-Pb dating of gabbro and basalt in the Weitogou ophiolite yielded the exact age data of 488.2±2Ma and 501.1±2.2Ma. The isotope data have filled the gaps of the ophiolite data in this area, and reflected the existence of remains of the ancient ocean in this area. The comprehensive regional geological characteristics suggest that the early period of the oceanic basin was at the initial stage,but at the late stage basalt was formed in an oceanic ridge expanding center environment. The Early Cambrian period was the flourishing period of the development of the oceanic basin, the late oceanic crust was formed in the late Ordovician period, and the late Silurian basin was basically closed together with later greenschist facies metamorphism.
Keywords:Meicaogou ophiolite  geochemistry  LA-ICP-MS zircon U-Pb ages  tectonic significance
本文献已被 CNKI 等数据库收录!
点击此处可从《地质通报》浏览原始摘要信息
点击此处可从《地质通报》下载全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号