地质通报2012，Vol.31Issue(2)：241-249,9.
滇西腾冲地区龙川江河谷上新世火山岩SHRIMP锆石U-Pb年龄及其地球化学特征
SHRIMP zircon U-Pb dating and geochemical analysis of the Pliocene volcanic rocks from Longchuanjiang valley, Tengchong area, western Yunnan Province
摘要
Abstract
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 Ma±0.11 Ma). The volcanic rocks are rich in alkalis (Na2O=3.53- 3.66 wt%, K2O=3.33-3.64 wt%) and calcium (CaO=4.04-5.05 wt%). They contain high Ba (lOSyxlO^-lHSxlO"*), Sr (502.0x10"^ 650.7X1CT'), REE (2REE=315.53xl(T6~365.16xl(r6), and Zr(308.8x 10^-382.2x10"^. These 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.关键词
SHRIMP锆石U-Pb年龄/火山岩/上新世/腾冲地区Key words
SHRIMP zircon U-Pb age/ volcanic rock/ Pliocene/ Tengchong area分类
天文与地球科学引用本文复制引用
石玉若,吴中海,范桃园,仝亚博,杨振宇..滇西腾冲地区龙川江河谷上新世火山岩SHRIMP锆石U-Pb年龄及其地球化学特征[J].地质通报,2012,31(2):241-249,9.基金项目
中国地质调查局地质调查项目《泛亚铁路大理至瑞丽沿线地质构造综合研究》(编号:1212010814054)、《西南地区活动构造域应力场模拟》(编号:1212010911049)、《青藏高原东南缘重要活动断裂厘定与活动构造体系综合研究》(编号:1212011120163)和《云南1∶5万马厂幅、道街坝幅区域地质调查》(编号:1212010784004) （编号:1212010814054）
