新疆西昆仑库地复理石源区性质及构造背景分析

Tectonic setting and provenance of the Kudi flysch in west Kunlun mountains, Xingjiang province.

出露于库地北一些克沟中的复理石作为西昆仑库地蛇绿岩的基本组成单元之一,其本身具有重要的大地构造位置。但长期以来,有关其形成的构造环境分析却尚属空白。笔者等在对该套复理石沉积序列详细分析的基础上,本文从沉积大地构造学的角度,利用岩石矿物、主量元素、微量元素及稀土元素等地球化学数据对其母源区性质及构造背景进行了一系列分析判别,确定其形成的构造环境为大洋岛弧的弧前盆地。

A set of deep-sea turbidite outcropped in Yexikegou of northwestern Kudi, west Kunlun Mountains has been studied in detail through petrologic and geochemical methods to determine its source rock types and tectonic settings. This flysch has been considered one important component of Kudi ophiolite zone, which is one of the five suture zones found in Tibet Plateau, the northernmost border of the Gandwana plate. So far, the source rock types and tectonic settings of this flysch set have not been studied in detail, which give rise to a lot of different opinions about its origin and evolution history. In this paper, we use geochemical data from FXR and ICP-MS analysis as well as statistic petrological data from sedimentary rock samples collected in Yixiekegou to discuss its source rock features and tectonic settings. Through different methods and discriminant diagrams, we got similar result. This flysch set should be formed in a fore-island-arc basin tectonic environment.