西北地质2012，Vol.45Issue(1)：124-133,10.
青海鄂拉山地区三叠系洪水川组火山岩地球化学特征及构造环境
Geochemistry and Tectonic Setting of Marine Volcanic Rocks of Elashan Area in Qinghai
摘要
Abstract
Elashan magmatic belt, an intersection location for East Kunlun, West Qinling and South Qilian orogenic belt, has complex internal structure and is an important junction in western China and ore concen-tration area in Qinghai. Marine volcanic widely outcrops in Elashan area and the rock types are ainly amyg-daloidal basaltic andesite, amygdaloidal andesite, andesitic volcanic breccia, andesitic crystal-vitric tuff debris, andesitic breccia tuff lava, dacite and rhyolite. Marine volcanic rocks occurs by the volcanic strata, or laminated and lenticular shapes in the Suolaqu sandstone, Xingfucun fine-turbidite and Hekashan coarse-turbidite of the Hongshuichuan Formation, which is the product of a marine environment eruption. Chemical composition of volcanic rocks similar with the average chemical composition of island arc calc-al-kaline andesite, The average SEu value is 0. 75 indicating a weak negative anomalies, (La/Sm)N, (Gd/ Yb)N values of the average were 5. 09, 1. 76, and There are significantly fractionated between light and heavy rare earth elements and enrich in LREE. The trace elements such as Ba, Rb and Th are strongly enriched and Ti, Cr and other elements are depleted. The Th× Ta/Hf2 value is between 0. 029 to 0. 162, shows volcanic arc character. From the above, volcanic rocks of the Hongchuichuan Formation produced in stretching after the collision environment.关键词
鄂拉山岩浆岩带/构造结/火山岩/拉伸环境Key words
Elashan magmatic belt/tectonic knot/volcanic rocks/stretch environment分类
天文与地球科学引用本文复制引用
李善平,李永祥,潘彤,白宗海,王瑾,舒树兰,李小雪,张志青,赵海霞..青海鄂拉山地区三叠系洪水川组火山岩地球化学特征及构造环境[J].西北地质,2012,45(1):124-133,10.基金项目
973计划前期研究专项课题(2010CB434808) （2010CB434808）
青海省科学技术厅重大科技项目(2010-J-A1) （2010-J-A1）
