SOME CHARACTERISTICS OF THE OROGENIC BELTS IN QINGHAI-TIBET PLATEAU

The Qinghai-Tibet plateau can be divided into a northern and a souther n part, with the Kunlun central thrust forming the boundary. The north ern orogenic belts developed on the rigid basement, starting with rift ing and geosynclines in the preorogenic stage, followed by collision t o form mountains, and postorogenic deformation, mainly producing overt hrusting and overlapping structures. The southern counterparts develop ed on a flexible basement, characterized by strong activity, and polyc yclic opening and closing, with well defined oceanic basins and widesp read terrigenous deposits on both flanks in the preorogenic stage, and complicated deformation in the postorogenic stage with a large number of strike-slip faults besides overthrusting and overlapping structure s. The overall tectonic framework is a series of unique orogenic belts in the Qinghai-Tibet plateau. There are numerous orogenic belts devel oped in the Qinghai-Tibet plateau, such as the Himalayas, Gangdise, Ta nggula, Hoh Xil, Kunlun and Qilian mountains. These belts provide valu able information on the evolution of the lithosphere. Therefore, it is important to summarize the main characteristics of the orogenic belts . Copyright (C) 1996 Elsevier Science Ltd