沉积与特提斯地质2016，Vol.36Issue(1)：30-37,8.
川西江浪穹窿二叠系变玄武岩的地球化学特征与岩石成因
Geochemistry and petrogenesis of the Permian metabasalts in the Jianglang dome, western Sichuan
摘要
Abstract
A succession of bedded metabasalts occurs in the Permian strata in the Jianglang dome, western Sichuan. These rocks have well-defined pillow structures, and are composed mainly of hornblende (~80%) , plagioclase (~15%) and minor quartz ( <3%) and magnetite (~2%) . The results of research in this study have disclosed that the metabasalts are characterized by low SiO2 ( an average of 44. 14%) and TiO2 ( an average of 1. 79%), high TFe2O3(an average of 13. 95%) and MgO (an average of 11. 64%); slightly right-leaning REE distribution patterns and unmarkedly Ce and Eu anomalies;enrichment of large ion lithophile elements Rb, Ba and U, and depletion of high field strength elements Nb, P, Zr and Hf;low La/Sm ratios (2. 71-2. 26), (Th/Ta)PM ratios (1. 36-1. 14) and (La/Nb)PM ratios (1. 78 -1. 33). The above-mentioned results show that the Perian metabasalts in the Jianglang dome may be assigned to ocean-floor basalts, and remnants of palaeo-Tethyan oceanic crust. The magmas may be derived from the depleted mantle mixed with minor enriched mantle components, and were not contaminated with crustal matter during the ascending processes. Instead, they may be subjected to the crystallization differentiation of ilmenite. Compared with the Emeishan basalts, the metabasalts in the study area are not the products of the Late Permian Emeishan basaltic magma activities.关键词
变玄武岩/地球化学/岩石成因/二叠系/江浪穹窿/川西Key words
metabasalt/geochemistry/petrogenesis/Permian/Jianglang dome/western Sichuan分类
天文与地球科学引用本文复制引用
陈道前,张惠华,冯孝良,唐高林,代堰锫,李同柱..川西江浪穹窿二叠系变玄武岩的地球化学特征与岩石成因[J].沉积与特提斯地质,2016,36(1):30-37,8.基金项目
中国地质调查局矿产资源评价项目( 1212011085139 )、成都地质调查中心青年科学基金项目(所控基[ 2015 ]-05)资助 （ 1212011085139 ）
