北祁连早古生代香毛山混杂岩的有关问题

ON THE EARLY PALAEOZOIC XIANGMAOSHAN FORMATION IN THE WESTERN PART OF NORTHERN QILIAN MOUNTAINS

对祁连山西段香毛山组正层型及其周边地区的地质调查和岩石学、地层古生物学研究发现,原划香毛山组并非正常的正式岩石地层单位,而是一个奥陶系蛇绿构造混杂岩带。在介绍该混杂岩的物质组成的基础上,对其构造性质进行了讨论。认为该混杂岩带是奥陶纪北祁连洋壳向北俯冲消减——镜铁山—捷达坂微陆块与东大窑—妖魔山—石灰沟岛弧带碰撞而形成的地壳缝合带。

Based on regional survey, lithostratigraphy, and biostratigraphy,the Xiangmaoshan Formation in the western part of northern Qilian Mountains is interpreted as an Ordovician ophiolite melange. This melange was first formed in the northern consummation and subduction zone of the northern Qilian ocean and island arc. Susequently, the collision with the Jingtieshan landmass and island arc belt led to the tec- tonically complex melange.