THE PROVENANCE OF TAKLAMAKAN DESERT SANDS——TO TRACE THE CENOZOIC PALAEO-OCEAN

The Taklamakan Desert is located between 37°N to 41°N of west China with a total area of 337,600km². It is the 2nd largest mobile desert in the world. Sand dunes are the major features, with an average height of 100~200 meters. Some are even 200~300 meters in height. The study mainly concerns the original provenance of such a thick layer of dune sands. So far multidisciplinary studies have been carried out in this region, including the structural outline of the Tarim basin, where the desert is located, elevated channel valleys, sedimentary facies of bedrock strata, microfossils, petroleum and natural gas resources, gypsum and salt lake strata, thick layer of the desert mobile sands, and surface textures of quartz sands of the desert, etc. All the evidence indicates that the desert sands were originated from the desiccated Miocene ocean. During that time, the Taram basin was under a marine environment as part of the New Tethys Ocean. During late Miocene of 10~5 million years ago, the New Tethys Sea there was closed by elevated surrounding mountains, and became an inland basin later with scattered lakes and swamps, then, gradually dried up to be a desert. Thus, the Miocene paleo-ocean was the sandy material foundation for the development of the Taklamakan Desert. In fact, there were multiple sources of sandy materials:weathering and denudation formed gravel sands; mountain glaciers produced sandy gravel and dust; pluvial fan deposited sands and gravels; wind blowing sands, river and lake sands, etc. However, the major provenance of sands is the Miocene paleo-ocean, and the marine sandy deposits within the ocean.