THE POST-OCEANIC GEODYNAMICS OF THE SOUTH TIEN SHAN REGION

Abstract

The subject of this paper is the structural and lithologic evolution of the earth crust in the South Tien Shan region, especially during the post-collision, platform and orogenic periods of its geologic history. The author describes the Mz-Kz intraplate and orogenic basins, including the Karakul, Zidda, Ravat, Zeravshan, and other basins, in terms of their tectonic structure, evolution, their positions in the general morphostructure of the recent orogenic belt, and its relationship with the crustal structure of the region. Particular attention is given to the problem whether the evolution of this territory in the Alpine time was or was not controlled by the previous stages of its evolution. It is concluded that the formation of the Alpine morphostructure of the region was controlled by the voluminous rock flows at different depth levels of the crust and lithosphere. The mechanisms of the material and structural reconstruction of the Paleozoic basement rocks are ranked as the processes of melange formation, voluminous cataclasis, brittle-plastic flow, and dynamic recrystallization, which had operated during the Alpine tectogenesis. The rock masses of the basement were proved to have experienced significant 3D movements during the platform and orogenic periods of the geologic history of the region discussed.