Tectonic framework of the eastern segment of the Central orogenic belt of China

Abstract：The author presents the main results of the latest geophysical investigations in the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt, analyzes the general characteristics of the lithospheric structures in the Dabie-Sulu terrane, and makes a comparison of these characteristics with those beneath the East Qinling and Tongbai terranes observed by previous workers. The crustal structure in the eastern segment of the Central orogenic belt reflects the northward deep intracontinental subduction of the Yangtze craton. The continental crust was subducted at angles of about 20°-30°. As the subduction angles were gentle, an open backland basin developed in the eastern segment of the orogenic belt, and the basement structure below the basin still has the characteristics of the plate convergence of the orogenic plate. The manifestations of large-scale magmatic intrusions occurring in the upper-mid crust in the cores of the orogenic belt were related to post-orogenic geological processes. The Early Mesozoic Dabie-Sulu UHP metamorphic belt might still exist at the deep levels of the crust below the East Qinling and will not be exposed on the surface today.