Deposit Response to Important Tectonic Events of Cenozoic Plateau Uplift, East Segment of Eastern Kunlun Mountains

Five important tectonic events in Cenozoic can be divided according to the study of its stratigraphic sequences and relief, drainage system and environment change in the east of the eastern Kunlun Mountains. The first discovery of the paleosoil and paleokarst, including karst breccia and stalactite, on the main planation surface about 5 400 m high in the area suggests that the fine clastic deposits of the upper Tuotuohe Formation and the gypsum deposits of the Wudaoliang Formation are the response to the forming period of the main planation surface in Miocene epoch. The distribution of the main planation surface nowadays shows a range and basin relief style with E-W extension. This elevation differentia reflects disequilibrium in the post-tectonic uplift, which should be the result of differentiated block uplifting since Miocene. While a series of alluvial sand and gravel deposits in middle Early Pleistocene, about 1 525.5 ka, can be regarded as the deposit response to the C episode of the Qinghai-Xizang tectonic movement, reflected in the intensive relief uplifting and formation of the Buerhanbud a Mountain near the Alake Lake. However, in the late Early Pleistocene, about 1 113.9-836.3 ka, lakeshore gravel deposits were deposited first and then they changed into alluvial gravel and sand deposits at the Chahaxili area. This could be regarded as the deposit responsing to the Kunlun-Yellow River movement, indicated in the intensive uplifting and formation of the Maerzheng-Buqing Mountains. The development of the moraine deposits in the early Middle Pleistocene suggested that the elevation in the study area could have reached a hydrosphere frozen altitude after the Kunlun-Yellow River tectonic movement. Whereas the Gonghe tectonic movement is represented by the strong erosion of the Qaidam drainage system before the terrace T5 deposition along the main river, cutting through the main Buerhanbuda Mountain divide, capturing the Gonghe paleolake drainage system, and the unconformity of the Late Pleistocene pluvial and alluvial deposits over the Middle Pleistocene pluvial and alluvial deposits.