Modelling the collisional and sedimentary evolution of the western part of the Tien Shan
2017. "Modelling the collisional and sedimentary evolution of the western part of the Tien Shan", Geological Evolution of Central Asian Basins and the Western Tien Shan Range, M.-F Brunet, T. McCann, E. R. Sobel
Download citation file:
Based on new structural and petrological investigations, we present two crustal-scale cross-sections of the Kyrgyz South Tien Shan, and correlations of main faults and units between Kyrgyzstan and China. The overall structure corresponds to a doubly-vergent mountain belt. The Kyrgyz and Chinese areas exhibit identical structural and metamorphic histories. To the west, the Atbashi Range comprises high-pressure oceanic and continental units stacked by north-verging thrusts above a low metamorphic accretionary prism. High-pressure (HP) gneisses are bound to their south by a south-dipping detachment exhibiting mantle relicts. The high-pressure oceanic and continental units underwent similar pressure–temperature (P–T) paths with peak conditions of around 500 °C–20 kbar, followed by rapid exhumation. The overall south-dipping structure and kinematics indicate a south-dipping subduction of the Central Tien Shan Ocean at 320–310 Ma, ending with the docking of the Tarim block to the Kazakh continent. To the east, the Pobeda Massif shows a narrow push-up structure. A major north-vergent thrust exhumes deep-crustal-level granulites, constituting the highest summits, which were thrust towards the north onto low-grade Devonian–Carboniferous schists. The southern part of South Tien Shan is made up of a south-verging thrust stack that formed later during ongoing convergence, reactivated throughout post-30 Ma phases.