西天山造山带构造单元划分与构造演化

Tectonic division and regional tectonic evolution of West Tianshan organic belt

西天山造山带位于北亚造山区的南部,为哈萨克斯坦-准噶尔古板块与塔里木古板块的交会处,由古生代陆缘岩系、洋壳残片和前寒武纪微陆块等拼贴增生而成,其构造演化过程成为新疆北部的古亚洲洋演化的缩影。经历了太古代至早元古代的古陆核形成、中—晚元古代古天山洋盆的演化,至晚元古代形成统一的新疆古陆的一部分。晚元古代天山地区作为古亚洲洋的一部分开始裂解,至寒武纪进入扩张的高峰,奥陶纪—石炭纪古俯冲带形成,古洋盆持续收缩,晚石炭世天山古洋盆关闭,统一大陆地壳形成,中新生代进入陆内演化阶段。

Located in the southern part of Central Asia, the West Tianshan organic belt lies at the juncture between the Kazakhstan- Junggar ancient plate and the Tarim ancient plate and is composed of Paleozoic epicontinental rock series, oceanic crust relicts and Precambrian microlandmass. Its structural evolution process is a miniature of the evolution of the Northern Xinjiang paleo-Asiatic Ocea. It experienced the formation of continental nucleus in Archean-early Proterozoic period, the evolution of Ancient Tianshan oceanic basin in late Proterozoic period, and the generation of a unified Xinjiang part of Gondwana in late Proterozoic period. In late Proterozoic period, Tianshan region, as a part of the paleo-Asiatic Ocean, began cracking; in Cambrian period this region entered the peak stage of expansion; in Ordovician-Carboniferous period, the ancient subduction zone was formed, and the ancient ocean basin was continually contracted; in Late Carboniferous period, the Tianshan ancient ocean basin was closed, with the formation of an unified continental crust; in Middle Cenozoic period, the region entered into the intracontinental evolution stage.