Progress in paleogeographic study of the Tibetan Plateau

This article summarizes research progress in some basic problems on paleogeographic revolution of the Tibetan Plateau in the last 50 years, especially recent decade. Based on reviews of current viewpoints and analysis of Miocene and Pliocene paleogeographies, it was suggested that altitude of the Tibetan Plateau was less than 1000m before 3.6Ma BP and intense uplift of the plateau began at that time. The ages of last three glaciations in the plateau are 725～581,289～136 and 82～10ka BP respectively, which are comparable with oxygen isotopic stages in deep sea. Large ice sheet did not exist in the Tibetan Plateau in the Maximum Glaciation of Pleistocene. Environmental changes were frequent with high amplitude and desiccation occurred in the Tibetan Plateau since the last interglacial period. Important phases and events of paleogeographic evolution in Cenozoic are: tropical and subtropical lowland controlled by planetary wind system between 38 and 22Ma BP, appearance of paleo-monsoon and development of main planation surface between 22 and 3.6Ma BP, intense uplift resulting in the formation of the modern monsoon and development of water system between 3.6 and 1.7Ma BP, entrance of cryosphere and maximum glaciation between 1.1 and 0.6Ma BP, and intense uplift and desiccation of climate in the inner plateau. Finally, some important problems need to be researched in future are suggested. It is indicated that key to breakthroughs in paleogeographical research lies in analysis of depositional basins and stratified landforms in and around the plateau, precise dating and explanation of high-resolution environmental information.