Provenance of Taklimakan Desert aeolian sediments based on rare earth elements signatures

Abstract

The aeolian sediment source controls the formation and development of sand seas. The Taklimakan Desert is China's largest desert and contains diverse dune types. Their sediment sources have attracted much attention, but the sources are disputed: some believe that the Kunlun Mountains to the south are the sources, whereas others suggest that the Tianshan Mountains to the north are the sources. However, a lack of research on the spatial variation of the sand sources limits our understanding of the formation and evolution of the desert's landforms, which makes it difficult to predict, prevent, or mitigate sandstorms. To improve our understanding, we collected sediment samples from six dune types and one dry lake deposit from the Taklimakan Desert. We used the sediment rare earth elements signatures to identify their sources and analyse the spatial variation of these elements and their ratios. We found the following: (1) The rare earth elements (REE) signatures were similar throughout the sand sea and in all sand dune types. (2) The main sediment source was the western part of the Kunlun Mountains, the Altyn Tagh Mountain and oases at the southern edge of the Tianshan Mountains, with sediments generated by river hydrology and wind. (3) The dry lake deposit differed from the sand dunes due to its much higher silt and clay contents, making it more akin to fluvial (river-derived) deposits in composition. (4) The homogeneity of the dunes resulted from the combination of river sediments and the wind regime. Our results provide insights into aeolian dune formation and development and will have implications for understanding other deserts.