|
|||||
|
|
| 西藏雅鲁藏布江缝合带西段东波蛇绿岩中锆石U-Pb定年及地质意义 | |
| 引用本文： | 熊发挥,杨经绥,梁凤华,巴登珠,张健,徐向珍,李源,刘钊.西藏雅鲁藏布江缝合带西段东波蛇绿岩中锆石U-Pb定年及地质意义[J].岩石学报,2011,27(11):3223-3238. |
| 作者姓名： | 熊发挥 杨经绥 梁凤华 巴登珠 张健 徐向珍 李源 刘钊 |
| 作者单位： | 1. 大陆构造与动力学国家重点实验室,中国地质科学院地质研究所,北京100037 2. 中国地质调查局天津地质调查中心(天津地质矿产研究所),天津,300170 3. 中国地质大学地球科学与资源学院,北京,100083 |
| 基金项目： | 本文受国家自然科学基金重点项目(40930313)、国家行业专项 (SinoProbe-05-02)、创新研究群体科学基金项目(40921001)和中国地质调查局工作项目 (1212011121263、1212011121272) 联合资助. |
| 摘 要： | 西藏东波蛇绿岩位于雅鲁藏布江缝合带西段,由地幔橄榄岩、辉石岩和辉长岩等组成.地幔橄榄岩主要为方辉橄榄岩、纯橄岩和少量二辉橄榄岩.地幔橄榄岩中有少量辉石岩和辉长岩的脉岩,宽约1m,走向北西与岩体的构造线方向基本一致.辉石岩由90％透辉石(Wo=48、En =46、Fs =6),少量的斜顽辉石(Wo=2、En=82、Fs=16),5％的斜长石(An =90)和透闪石组成.辉长岩主要由透辉石(Wo =47、En=36、Fs=17)、斜长石(An =47)及少量的镁角闪石组成,岩石成分以低K2O和P2O5含量(均＜0.1％)和亏损的LREE模式为特征,显示N-MORB岩石的特征.经LA-ICP-MS锆石U-Pb原位微区测定,获得辉石岩和辉长岩的年龄分别为130±0.5Ma、128±1.1Ma.首次给出了东波蛇绿岩年龄,代表了东波地区新特提斯洋海底扩张的时代. |
| 关 键 词： | 辉石岩 辉长岩 锆石U-Pb年龄 东波蛇绿岩 |
| 收稿时间： | 2011/6/10 0:00:00 |
| 修稿时间： | 2011/9/25 0:00:00 |
Zircon U-Pb ages of the Dongbo ophiolite in the western Yarlung Zangbo suture zone and their geological significance. |
|
| XIONG FaHui,YANG JingSui,LIANG FengHu,BA DengZhu,ZHANG Jian,XU XiangZhen,LI Yuan and LIU Zhao.Zircon U-Pb ages of the Dongbo ophiolite in the western Yarlung Zangbo suture zone and their geological significance.[J].Acta Petrologica Sinica,2011,27(11):3223-3238. | |
| Authors: | XIONG FaHui YANG JingSui LIANG FengHu BA DengZhu ZHANG Jian XU XiangZhen LI Yuan and LIU Zhao |
| Institution: | State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Tianjin Institute of Geology and mineral Resources, CGS, Tianjin 300170, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China |
| Abstract: | The Dongbo ophiolite in the western Yarlung Zangbo suture zone contains mantle peridotite, pyroxenite and gabbro. The mantle peridotite consists of harzburgite, dunite and minor lherzolite. Some pyroxenite and gabbro veins of variable size occur in mantle peridotite, and most of them strike NW, parallel to the main structure of the mantle peridotite. The pyroxenite consists of about 90% diopside (Wo=48, En=46, Fs=6), 5% plagioclase (An=90) and small amounts of clinoenstatite (Wo=2, En=82, Fs=16) and tremolite. The gabbro contains pyroxene (Wo=47, En=36, Fs=17), plagioclase (An=47) and minor magnesium amphibole. The gabbros are characterized by low contents of K2O (<0.1%) and P2O5 (<0.1%), and depleted LREE patterns, similar to that of N-MORB. U-Pb dating of zircons from the pyroxenite and gabbro by LA-ICP-MS yielded ages of 130±0.5Ma and 128±1.1Ma, respectively. These data provide the first age constraint on the Dongbo ophiolite, and show that it belongs to the Neo-Tethyan system of the Yarlung Zangbo suture zone. |
| Keywords: | Pyroxenite Gabbro Zircon U-Pb age Dongbo ophiolite |
| 本文献已被 CNKI 万方数据 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 | |