Not all gravel deserts in northern China are sources of regionally deposited dust

Abstract

Loess and dust deposits are the longest and best-preserved terrestrial record of climate changes available, and one of the most important records is the Chinese Loess Plateau. Ascertaining the provenance of the wind derived dust material is critical in our understanding of climate variations, atmospheric dust transport and controls on dust generation. To determine the dust sources of the CLP, major and trace element data have been obtained from 202 dust samples and compared to 122 published data of dust source regions throughout northwestern China. The results demonstrate that the northeastern Tibetan Plateau is the major dust source for the depositional desert, sandy land and loess regions (e.g. Badain Jaran Desert, Alxa Plateau, CLP). However, the Qilian Mountains causes some differences of dust sources for Lanzhou, Xi'an when compared with the CLP. The most important finding is that not all gravel deserts in north China are dust sources for loess sequences at Lanzhou, Xi'an and CLP, which means that previous dust emission quantity assessments may be overestimations. The northeastern Tibetan Plateau, Tarim, the middle and eastern area of the Hexi Corridor Desert, Heihe River Basin, Badain Jaran Desert, and the middle and east area of the Alxa Plateau are the main dust sources, supported by the geochemical characteristics of the samples, regional geomorphology, and near surface wind dynamics.