Carboniferous–Permian tectonic evolution and sedimentation of the Turpan-Hami Basin, NW China: Implications for the closure of the Paleo-Asian Ocean

Abstract

The tectonic evolution and sedimentary characteristics of the Carboniferous–Permian rocks of the Turpan-Hami Basin have been analysed. Initially, a joint inversion of gravity, magnetic, seismic data and the established model of electrical profiles was synthesized to create a new geological interpretation. Discussion on the tectonic characteristics of piedmont zone in the northern part of the basin then followed. According to the analysis of balanced cross-sections, the tectonic evolutionary history of Carboniferous–Permian sedimentary rocks of the Turpan-Hami Basin can be divided into three stages: an extensional stage in the Carboniferous, a tectonic transition stage in the Early Permian, and a compression and inversion stage after the Middle Permian. It is found that the tectonic evolution controlled the sedimentary facies under these three stages and the sedimentation evolution has undergone marine facies, marine–lacustrine transitional facies and lacustrine facies. Meanwhile, based on the recent seismic, gravity, magnetic and electrical data, and combined with the field surveying of outcrops, the residual distribution of Carboniferous–Permian strata is characterized by the widely distributed residual Upper Carboniferous, except for the southern Liaodun Uplift and locally in the eastern area, and the denudation of Middle Permian strata mainly distributed in the Turpan Depression and the Turpan-Hami Depression. After comprehensive analysis of the sedimentary facies and erosion of Permian strata, it is concluded that the tectonic evolution and sedimentation of the Turfan-Hami Basin can be used as a constraint on Permian subduction-related accretionary orogenesis of northern Xinjiang, NW China and the closure time of the Paleo-Asian Ocean.