Tectonic division and Paleozoic ocean-continent transition in Western Tianshan Orogen

Western Tianshan Orogen, located in the conjunction of the Kazakhstan-Junggar Plate and the Karakum-Tarim Plate, has been regarded as the collision zone and metallogenic zone consisting of a series of Precambrian blocks, Paleozoic oceanic crust, and continental marginal arcs. The study of the orogenic-metallogenic processes of western Tianshan Mountain have received extensive attention. In this paper, the authors established the tectonic framework of western Tianshan Orogen in the Paleozoic on the basis of the tectonic division, and proposed a five-stage model of the tectonic evolution in Paleozoic:Rodinia supercontinental breakup and the formation of the early Paleozoic archipelagic ocean in northern Tianshan Mountains (Z-O₂), closure of the early Paleozoic archipelagic ocean in northern Tianshan Mountains and the incipience of the southern Tianshan oceanic basin (O₃-S), formation and development of the northern and southern Tianshan oceanic basins in the late Paleozoic (D-C₁), closure of the northern and southern Tianshan oceanic basins and the subsequent formation of Tianshan orogenic belt (C₁-C₂) and, finally, the post-collision stage of the intraplate environment (C₂-P).