Evidence for enhanced aridity in the Tarim Basin of China since 5.3 Ma

Thick Cenozoic deposits formed from the erosion of the northern evolving edge of the Tibetan Plateau provide opportunities to study the exhumation history and climatic changes within the region. Such deposits are important because they are located in an actively deforming mountain belt as well as in a rain shadow of the Tibetan Plateau. Multi-proxy studies indicate that hyperarid climate has prevailed since 5.3 Ma ago within the basin. This information, together with the geometry analysis of syntectonic deposits of the Sanju Anticline, which indicate tectonic deformation at 5.3 Ma, enable us to better understand the interlay between climatic changes and tectonic uplift. Our results suggest that the tectonic uplift of the Kunlun Mountains at 5.3 Ma must have been one of the significant regional tectonic events, and the uplifted elevation of the Kunlun Mountains more effectively blocks the penetration of moisture from the Indian monsoon into the Tarim Basin and thus enhances the rain shadow effect. This can account for the increasing aridity as well as the formation of the world's second largest active sand desert (the Taklimakan Desert) in the Tarim Basin initiated at 5.3 Ma ago.