DISCOVERY OF THE EARLY PLEISTOCENE KUNLUNHE CONGLOMERATE IN GOLMUD OF QINGHAI PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE

The Kunlun River originating in the Kunlun Mountains is one of main tributaries of the Golmud River. The reported Neocene and Quaternary strata are mainly distributed in the Kunlun Pass area, whereas in the valley of the Kunlun-Golmud River only occur the strata younger than the Middle Pleistocene. Therefore, a conception of the "Kunlun-Huanghe movement" was proposed for the time span of 1.1 to 0.6 Ma. In this paper we report the discovery of over 20m of Ca-cemented fluvial gravels in the valley of Kunlun River, named the Kunlunhe conglomerate. Its distribution, the unconformity with such overlying strata as the Nachitaigou Formation, the Sanchahe Formation and the deposits on lower terraces, as well as the ESR dating of the Ca-cemented gravels (1042 ± 104 ka and 1269 ± 126 ka), all suggest that the Kunlun-Golmud River valley had been formed before 1.27~1.42 Ma, and cut deeply down to its present bottom. After that, The repeated incisions and accumulations after that were not due to tectonic movements, but to erosion and movement caused by climatic changes during the glacial-interglacial periods. Furthermore, the strong uplift of the Kunlun Mountains with respect to the Qiadam Basin should occur before at least 1.27~1.42 Ma.