Pre-Cenozoic geologic history of the central and northern Tibetan Plateau and the role of Wilson cycles in constructing the Tethyan orogenic system

Abstract

In order to better constrain the evolution of the Tethyan orogenic system, we conducted an integrated investigation involving U-Pb dating of igneous and detrital zircon, geochemical analysis of igneous rocks, compositional analysis of sedimentary strata, and a synthesis of existing work across the Qilian Shan, Qaidam Basin, and the Eastern Kunlun Range of central and northern Tibet. This effort reveals five stages of arc magmatism at 1005-910 Ma, 790-720 Ma, 580-500 Ma, 490-375 Ma, and 290-195 Ma, respectively. Arc activities were interrupted by repeated continent-continent collision followed by ocean opening along the older suture zones first created in the Neoproterozoic. This suggests that Wilson cycles have played a controlling role in constructing the southern Asian continent. The magmatic history and regional geologic constraints allow us to construct a coherent tectonic model that has the following key features. (1) The linked South Qilian suture in the west and North Qinling suture in the east formed the northern boundary of the coherent Kunlun-Qaidam-North Qinling Terrane in the early Paleozoic. (2) The Songpan-Ganzi Terrane has been the western part of the Yangtze craton since the Neoproterozoic.