SHRIMP Zircon U-Pb Dating and Geochemical Analysis of the Pliocene Volcanic Rocks from Longchuanjiang Valley, Tengchong Area, Western Yunnan Province

详细信息   

• 责任者：Shi Yuruo (Institute of Geomechanics ; Chinese Academy of Geological Sciences ; Beijing 100081 ; China) ; Wu Zhonghai
• 刊名：Geological Bulletin of China
• 出版年：2012
• 卷期：31(2)
• 关键词：粗安岩 ; trachyandesite ; 粗面岩 ; trachyte ; 地球化学 ; geochemistry ; 铀—铅计时 ; U-Pb dating ; 云南 ; Yunnan Province
• 页码：p.241-249
• 图表：5 illus., 2 tables, 19 refs.
• 分类号：0801
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

摘要

In this paper, Pliocene ages （ca. 2.8 Ma） of trachyandesite and trachyte from Longchuanjiang Valley in Tengchong area were yielded using SHRIMP Ⅱ in Beijing SHRIMP Laboratory. The ages of trachyandesite and trachyte correspond with each other within uncertainties and are taken to represent the time of eruption （2.81±0.11） Ma. The geochemical features are different from those of typical island arc volcanic rocks but show an affinity with contaminated asthenosphere-generated continental basaltic rocks. The Pliocene volcanic rocks from Longchuanjiang Valley in Tengchong area were derived from partial melting of an enriched mantle source, contaminated by large crustal materials in an intraplate extensional environment.