Multi-stage uplifts of the Qinghai-Tibet plateau and their environmental effects

Environmental changes in western China can be primarily attributed to the uplift of the Qinghai-Tibet Plateau.Studies of tectonic evolution of the Qaidam Basin, the Tu-Ha Basin, and the Tarim Basin and their response to uplift movements, suggest that the rising of the Qinghai-Tibet Plateau can be subdivided into three stages.Firstly, the plateau only existed along the Gongdese Mountains during the Paleogene, while western China was subsequently located in the latitude-direction climatic belts, most of which experienced peneplain conditions with extensive lacustrine and pan-basin deposits because of extension in the hinterland, similar to the present tectonic conditions of the East Asian Continent.Secondly, the initial uplift of the plateau occurred in the Early to Middle Miocene (~23-11.7 Ma), which formed the framework of the topography and structure of western China.Due to the presence of the newly uplifted plateau and the Great Hinggan Mountains, the Paleogene climate of Central Asia changed to the monsoon belts.The paleo-loess was formed at about 22 Ma and the Hipparion fauna appeared in this period, and a desertification environment existed in the northern part of the plateau.Finally, the latest strong uplift of the Qinghai-Tibet Plateau and adjacent mountains occurred at the end of the Early Pleistocene (0.9-0.8 Ma).This resulted from A-type intra-continental subduction of the Indian Plate beneath the Asian continent, representing the last phase of the Late Mesozoic-Cenozoic compressional tectonics.This uplift not only led to profound climatic changes in the plateau, which resulted in the most extensive glaciation and the widest cold prairie grassland in the Quaternary, but also to a global climate change, that may have influenced the glacial cover in the Arctic Circle.Meanwhile, because of this plateau uplift dynamics, the basin-mountain topography of western China was formed with the strongest tectonic deformation in the inner plateau and adjacent regions, including the deformation of the Qaidam Basin, the Hexi Corridor, and the two-way extrusion of the Kunlun Mountains, the Qilian Mountains, the Tianshan and Altai Mountains.Present day, uplift of the Qinghai-Tibet Plateau, has caused the high and cold grassland to disappear and the large scale desertification of western China.