Provenance of aeolian sand in the Kumtag Desert, northwestern China, inferred from geochemical data

The Kumtag Desert is one of the main deserts of northwestern China, and identifying the provenance of its aeolian sediments is of great importance for understanding its origin and subsequent evolution. In this study, 151 surface sediment samples from the Kumtag Desert and potential sand source areas, such as Altun Gobi, Beishan Gobi, Dunhuang Gobi, sand-gravel-moraines, and yardangs, were collected to study the provenance of aeolian sand based on geochemical characteristics, topographic data, river data, wind field data, etc. Low chemical index of alteration (CIA) values indicate that the surface sediment samples from the study area experienced weak geochemical weathering or even no weathering in the cold and dry surroundings. The dune sediments from the Kumtag Desert have K/Rb and K/Ba values that broadly overlap with those of samples from Altun Gobi, western Beishan Gobi, and sand-gravel-moraines in the desert hinterlands but have almost no overlap with samples from eastern Beishan Gobi and Dunhuang Gobi; these results indicate that Altun Gobi, western Beishan Gobi, and sand-gravel-moraines are the main sand source regions for the Kumtag Desert and that eastern Beishan Gobi and Dunhuang Gobi are not. The distribution area of yardangs is small, and the values of K/Rb and K/Ba are significantly different from those of the Kumtag Desert, indicating that yardangs are not a main sand source for the Kumtag Desert. Additional results, such as the distribution of rivers, regional sand transport potential, regional topography, and movement directions of sand dunes on the edges of the desert, further confirm the above conclusions. This study enhances the understanding of sand provenance in the Kumtag Desert.