Ages of Post-Collisional A-Type Granite and Constraints on the Closure of the Oceanic Basin in the Middle Segment of the Bangonghu-Nujiang Suture, the Tibetan Plateau
详细信息
- 责任者：Qu Xiaoming (Key Laboratory of Metallogeny and Mineral Resource Assessment ; Institute of Mineral Resources ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Xin Hongbo
- 刊名：Geochimica
- 出版年：2012
- 卷期：41(1)
- 关键词：A型花岗岩 ; A-type granite ; 板块碰撞 ; plate collision ; 西藏 ; Tibet
- 页码：p.1-14
- 图表：7 illus., 3 tables, 35 refs.
- 分类号：1702
- issnNo：ISSN0379-1726
- isbnNo：CN44-1398/P
摘要
quot;EnDivSummary">A group of A-type granite has been found in recent years in the middle segment of the Bangonghu-Nujiang suture.These granite bodies occur as stocks with exposed areas of less than 1 km2.Lithologically,these A-type granites include two types of biotite granite and granodiorite porphyry,which intrude into Cretaceous sedimentary rocks.Zircon U-Pb LA-ICP-MS dating for the three granite bodies indicates that they formed in the late stage of the Early Cretaceous.From their zircon U-Pb ages and post-collisional A2-type signatures,the authors infer that the Bangonghu-Nujiang middle Tethys ocean should be closed at least in the beginning of Early Cretaceous.