东天山晚古生代以来大地构造与矿产勘查

TECTONIC EVOLUTION SINCE THE LATE PALEOZOIC AND MINERAL PROSPECTING IN EASTERN TIANSHAN MOUNTAINS, NW CHINA

大地构造研究一直被认为是地球科学中的纯基础性理论研究,实际上它与矿产勘查工作关系也很密切,其结论可为资源评价特别是含矿潜力的确定,提供科学依据。通过近年研究东天山地区构造格架取得的新资料和新认识,对该区部分矿产的含矿潜力及找矿方向提出了初步建议。

Tectonics had been considered as a branch of geosciences for pure basic research, but it can also play an important role in human activities. Much attention has been paid in prospecting of mineral resources from tectonic research. It is found that some kinds of ore deposits occur only in a given tectonic setting and/or a special stage of tectonic evolution. And post- metallogenesis structural disturbance of the earth's crust, including uplift, thrust and strike-slip, will change the occurrence of ore deposits in the crust. The eastern Tianshan mountains is listed as one of the key areas in a new turn of reconnaissance of mineral resources. In addition, new ideas are put forward on the present structural style, late Paleozoic tectonic framework and evolution of The eastern Tianshan mountains, and its relation to neighboring Junggar, Beishan, and other areas. They mainly include: (1) major fault belts exist between Tarim, Kuruketag, central Tianshan and Tuna blocks which are respectively named as Kongquehe (Peacock river, northwards dip thrust), Kawabulak (southwards dip thrust), and Kangguertag (northwards dip thrust and superposed dextral strike-lip); (2) paleo-oceanic basin, precursor of the Kanggurtag belt, had occurred in the beginning of the Devonian; (3) ocean-continental framework of the area during the late Paleozoic was probably similar to an archipelago ocean; (4) tectonic evolution during the late Paleozoic could be divided into three stages, i.e., subduction from the Devonian to early Carboniferous, collision in the late Carboniferous, and post-collisional mantle-derived magma underplating and crustal extension from the end of the Carboniferous to Permian. Finally tectonic setting of The eastern Tianshan mountains is discussed and some new suggestions on ore prospecting are put forward.