Geochemical characteristics and dust source implications of loess deposits in the eastern Tibetan Plateau

Late-Quaternary loess deposits are widely distributed across the eastern Tibetan Plateau (ETP) and its adjacent regions, and provide valuable terrestrial archives of paleoenvironment in the ETP. However, there is still no consensus on the provenance of the Tibetan loess, which hinders our understanding of its source variations and paleoenvironmental implications. Using topsoil samples of ETP loess and north-western China, we systematically investigated the spatial variability in geochemical composition, and discussed the characteristics of the ETP loess elements and the possible provenance. The results show that the ETP loess is relatively depleted in Na2O, K2O, P2O5, Sr, Nb, Ba, Pb and Bi; while MnO, TiO2, V, Cr, Co, Ni, Y, Zr, La, Ce and Hf are relatively enriched compared with the upper continental crust (UCC). Geochemical compositions and source analyses showed that the Qaidam Basin, the Hexi Corridor and the Tarim Basin in northwestern China were not the main source of the ETP loess. The elemental characteristics of the ETP loess are broadly consistent, and similar to the characteristics of the major elements of surface sediments on the plateau, together indicating that the ETP loess materials were sourced mainly from the interior of the Tibetan Plateau. The source material of the Tibetan loess has been relatively stable since the Last Glacial Period. This result will be helpful to enhance our understanding of the dust processes in the Tibetan Plateau.