Size-differentiated REE characteristics and environmental significance of aeolian sediments in the Ili Basin of Xinjiang, NW China. (1st August 2017) - Chen, Xiuling
Graphical abstract: Size-differentiated REE characteristics can serve as more effective source tracers for aeolian sediments, allowing for a better the exact source(s) of the Ili loess. Highlights: Size-differentiated REE can act as improved provenance tracers for aeolian sediment. REE of the <2 μm particle is sensitive indicators to identify distant dust in the Ili Basin. REE of coarse fraction is effective to track proximal dust and regional circulations. Abstract: Aeolian loess in the Ili Basin is an important geological archive for studying the changes in paleoclimate and sources of dust particles. Size-differentiated rare earth elements (REE) may help to distinguish potential dust sources. This study investigates the size-differentiated REE characteristics from three sites including the Zhaosu loess and the Kekdala desert sediments from the Ili Basin, and the Chaona loess from the Chinese Loess Plateau (CLP). Our results show that the patterns of variation of the REE characteristics in different size fractions can act as improved source tracers for aeolian sediments. Moreover, the REE characteristics of the <2 μm particles are sensitive indicators for distinguishing dust particles transported over long distances in the semi-arid areas with limited pedogenesis such as the Ili Basin. However, it should be interpreted cautiously in the CLP due to the post-depositional chemical weathering. The REE characteristics of coarse fractions are effective tracers for tracking changes in proximal dust sources and regional boundary level circulations. Our study has implications for identifying the exact source(s) of the Ili loess, which is helpful to understand paleoclimate changes and westerly circulation patterns in Central Asia.