Geochemistry of the OIB-type Basalt from The Wumulong-Tongchangjie Area, Changning-Menglian Suture Zone: Its Petrogenesis and Tectonic Implications
详细信息
- 责任者：Lai Shaocong (State Key Laboratory of Continental Dynamics ; Department of Geology ; Northwest University ; Xi’an 710069 ; China) ; Qin Jiangfeng
- 刊名：Earth Science Frontiers
- 出版年：2010
- 卷期：17(3)
- 关键词：洋岛玄武岩 ; ocean-island basalts ; 元素地球化学 ; elements geochemistry ; 云南 ; Yunnan Province
- 页码：p.44-52
- 图表：7 illus., 1 table, 16 refs.
- 分类号：0801
- issnNo：ISSN1005-2321
- isbnNo：CN11-3370/P
摘要
Ophiolite mélange from the Wumulong-Tongchangjie area, Changning-Menglian tectonic zone mainly consists of ultrabasic and basaltic rocks. The ultrabasic rocks are mainly composed of harzburgite and dunite. They exhibit distinctive geochemical characteristics of extremely low CaO (<0. 1%), low rare earth element content (<5×10-6), (La/Yb)N=0.96~1.14 and (Ce/Yb)N=1.04~1.37, showing the depletion of light rare earth elements. It implies that the Changning-Menglian ancient ocean basin had undergone a whole evolutionary process from initial limited ocean basin to a mature ancient ocean basin.