于田县幅、伯力克幅地质调查新成果及主要进展

New results and major progress in regional geological survey of the Yutian County and Bolike sheets

发现其曼于特早古生代蛇绿混杂岩带和二叠纪普鲁-阿羌裂谷型火山岩带。确定苏巴什蛇绿混杂岩带的形成时代为石炭纪—中二叠世。查明阿尔金断裂延入西昆仑表现为转换断层的性质。认为其曼于特蛇绿混杂岩与库地蛇绿岩相当,代表震旦纪—早古生代原特提斯多岛洋内亲塔里木板块的小洋盆;苏巴什蛇绿混杂岩带归属于晚古生代古特提斯沟-弧-盆体系,为弧后陆缘小洋盆消减的产物,该盆地于中二叠世末褶皱,代表晚古生代弧-陆碰撞后的大陆增生;晚二叠世—三叠纪沉积及巴颜喀拉山群奠基于特提斯洋盆之上,在接受大量陆缘碎屑沉积的同时向北侧的古生代增生造山带之下俯冲,形成了昆仑山最南侧、规模最大的晚三叠世—侏罗纪二长花岗岩带,并最终实现洋-陆转化。

The Early Paleozoic Qimanyute ophiolitic mélange belt and Permian Pulu-Aqqan rift-type volcanic belt have been found. The age of the Subexi ophiolitic mélange belt has been determined to be Carboniferous-Middle Permian. It has been ascertained that after the Altun (Altyn Tagh) fault extends into the West Kunlun it is marked by a transform fault. It is thought that the Qimanyute ophiolitic mélange belt is equivalent to the Kuda ophiolite, representing a small ocean basin of the Tarim plate affinity within the Sinian-Early Paleozoic Proto-Tethys archipelagic ocean. The Subexi ophiolitic mélange belt belongs to a Late Paleozoic Paleo-Tethys trench-arc-basin system and is the product of subduction of a back-arc continental-margin small ocean basin. This basin was folded at the end of the Middle Permian, representing continental accretion occurring after the Late Paleozoic arc-continental collision. Late Permian-Triassic deposits and the Bayan Har Mountain Group are based on the Tethys oceanic basin, and while receiving large volumes of continental-margin clastic deposits they were subducted northward beneath the Paleozoic accretionary orogenic belt, thus forming the largest Late Triassic-Jurassic monzogranite belt at the southernmost side of the Kunlun Mountains and realizing the ocean-continent transformation at last.