西昆仑塔什库尔干混杂岩的地质特征及其大地构造意义

Geological features and tectonic significance of melange zone in the Taxkorgan area, West Kunlun

西昆仑塔什库尔干构造混杂岩带由古元古代基底岩片、震旦纪大陆板内裂谷玄武岩岩片、奥陶纪—志留纪复理石岩片、石炭纪—二叠纪火山弧岩片及高压变质岩片组成。根据高压变质、残余洋盆及岩浆弧的形成时间进行综合判断,混杂岩带形成于早古生代。该混杂岩带的发现对于确立康西瓦断裂带的性质和认识西昆仑地区的大地构造演化历史具有重要意义,进一步表明西昆仑地区在早古生代曾发生过板块俯冲和碰撞,并暗示麻扎-康西瓦断裂可能代表了原特提斯洋-古特提斯洋俯冲消减并最终闭合的界线。

The Taxkorgan tectonic melange belt in West Kunlun is composed of the Paleoproterozoic basement, the mainland Sinian phte rift basalt rock film, Ordovician-Silurian flysch rock film, Carboniferous-Permian arc volcanic rock and high-pressure metamorphic rocks. Integrated study of the high-pressure metamorphic and the remnants of oceanic basin and the timing of magmatic arc indicated that the formation of melange belt commenced in early Paleozoic. The confirmation of the melange belt Kangxiwar is of great significance to establish the nature of the fault zone and to understand the fi-amework evolution. This finding indicates that there have been plate subduction and collision durins the early paleozoic and suggested that the Mazar-Kangxiwar fault may represent the bound- ary of the original Tethys - the ancient Tethys subduction and final closure.