SHRIMP dating of the Bangong Lake SSZ-type ophiolite: Constraints on the closure time of ocean in the Bangong Lake-Nujiang River,northwestern Tibet

作     者：SHI RenDeng1,2 1 School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China 2 Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China (email: shird@***) 

作者机构：School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China 

出 版 物：《Chinese Science Bulletin》 (CHINESE SCIENCE BULLETIN)

年 卷 期：2007年第52卷第7期

页      面：936-941页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：Supported by the Ministry of Land and Resources (Grant No. 20010101) the National Natural Science Foundation of China (Grant No. 40572036 and 40610104005) 

主　　题：西藏 班公湖怒江缝合带 古海洋闭合时期 SSZ型蛇绿岩 SHRIMP 测年 

摘      要：The Bangong Lake ophiolite is located in the westernmost part of the Bangong Lake-Nujiang River suture zone. It is a tectonic mélange consisting of numerous individual blocks of peridotite, pillowed and massive lavas and mafic dykes with SSZ-type ophiolitic geochemical affinity formed at the end of a Wilson circle. The SHRIMP U-Pb ages of the co-magmatic zircon domains from one gabbroic dyke (Sample 01Y-155) range from 162.5±8.6 Ma to 177.1±1.4 Ma with an average of 167.0±1.4 Ma (n = 12, MSWD = 1.2), suggesting that the subduction of the Bangong Lake Neo-Tethyan Ocean started before the Middle Jurassic. It is inferred that the tectonic transform from spreading to subduction of the Neo-Tethyan Ocean began before the Middle Jurassic in the Bangong Lake area.