Comparisons of topsoil geochemical elements from Northwest China and eastern Tibetan Plateau identify the plateau interior as Tibetan dust source

Abstract

The high-altitude Tibetan Plateau (TP) is a potential substantial source of dust that could have major effects on the global dust cycle and lead to environmental change. Aeolian loess on the TP is a valuable archive for studying the history of dust activities. Identification of TP dust sources will deepen understanding of dust transport and atmospheric circulation patterns and their environmental impacts. However, consensus on the source of TP loess has not been reached, which hinders understanding of dust transport and paleoenvironmental explanations. In this study, topsoil and loess samples from Northwest (NW) China and eastern TP were used to systematically investigate the spatial variability in geochemical composition, and the element characteristics of the TP loess were used to identify its dust source. Compared with samples from NW China, the eastern TP topsoil and loess were relatively enriched in TiO2, MnO, Cr, Co, Y, Zr, Nb, La, Ce, and Hf, but relatively depleted in Na2O, MgO, CaO, Sr, and Pb. The geochemical composition and source analyses indicated that the dust from the Qaidam Basin, Hexi Corridor, and Tarim Basin in NW China was not the main contributing source to the TP loess. However, the elemental characteristics of the TP loess were broadly consistent, and element contents were similar to those of major and trace elements in surface sediments on the TP. Thus, the eastern TP loess was sourced primarily from the TP interior, revealing the TP as an important dust source in Asia.