Oligocene tectonic lithofacies paleogeography of the Tibetan Plateau

Based on the data obtained from 1:250 000 geological mapping conducted by CGS during 1996-2008 and the previous studies of Oligocene strata, the authors investigated the evolution of the Oligocene tectonic lithofacies paleogeography in the Tibetan Plateau. The paleogeographic configuration remained high in elevation on the eastern side and low in the western side; depressed basins were distributed in Tarim, Qaidam, Qiangtang, Hoh Xil and Chengdu; uplifted and erosional areas lay in Gangdisê, Himalayan and Karakorum; and the paleo-Yarlung Zangbo River flowed from eastern Nang County to western Khalatse. The evolution characteristics of the Oligocene tectonic-lithofacies paleogeography responded to the tectonic uplift of the Tibetan Plateau, with two strong uplift stages existent during 34-30Ma (Stage A) and 25-23Ma (Stage B).