新疆西昆仑库地混杂带中基性火山岩构造环境分析  

Tectonic settings of the basic igneous rocks in the Kudi ophiolite zone of West Kunlun Mountains, Xingjiang Province.

作　　者：方爱民[1] 李继亮[1] 刘小汉[1] 侯泉林[1] Lee Ik Jong 肖文交[1] 俞良军[1] 周辉[3] 

机构地区：[1]中国科学院地质与地球物理研究所岩石圈构造演化开放实验室,北京100029 [2]Polar Science Laboratory,Korea Ocean Research and Developrnent Institute,Ansan P.O.Box 29,Seoul 425-600 [3]北京大学地质系,北京100081

出　　处：《岩石学报》2003年第3期409-417,共9页Acta Petrologica Sinica

基　　金：中国科学院重要方向项目(编号:KZCX2-SW-119-3);国家自然基金(批准号:40172080)

摘　　要：库地北一些克沟基性火山岩是西昆仑库地蛇绿岩的重要组成单元之一,而有关其形成的构造环境仍存在很多争议,由此影响了对该蛇绿岩性质、形成和演化方面的深入认识。笔者在野外对一些克沟基性火山岩地质剖面进行了详细的观察,在综合前人研究资料的基础上,利用地球化学(主量、微量及稀土元素)及Sm/Nd同位素分析等数据对其构造背景进行了多种手段相结合的判别和分析,确定其形成的构造环境为洋内弧,从而为进一步确定库地蛇绿岩的形成环境提供了新的佐证。The basic igneous rocks, outcropped in Yexikegou, northwest of Kudi, is one of the most important components of the tectonically separated Kudi ophiolite in west Kunlun which is considered the northernmost border of the Gandwana plate as well as the oldest suture zone found in Tibet Plateau. So far, a lot of different opinions about its tectonic settings have been presented by different researchers, which gives rise to much confusion on the understanding upon its origin and evolutionary history. To clarify such confusion, a detailed field survey upon the geological section of the igneous rocks in Yexiekegou was conducted. In this paper, we use geochemical data from XRF, ICP-MS;and Sm/Nd isotope analysis as well as the published data in this area to make a synthetical determination upon its tectonic settings. Through different tectonic discriminant diagrams based upon major and trace element compositions of Yexiekegou basic igneous rocks together with their isotopic characteristics, accordant results can be obtained that they were formed in an oceanic island-arc tectonic environment. Therefore, it provides some new evidences for the constraint on the origin of Kudi ophiolite.

关 键 词：西昆仑 库地混杂带 基性火山岩 构造环境 大洋岛弧 

分 类 号：P588.145[天文地球—岩石学]