Provenance studies of aeolian sand in Mu Us Desert based on heavy-mineral analysis

Abstract

Provenance studies of aeolian sand are beneficial for understanding desert formation and evolution. The material source of aeolian sand in the Mu Us Desert remains controversial, and few studies have focused on its sand transport pathways. Thus, the heavy-mineral compositions of 92 modern aeolian sand samples, 23 fluvio-lacustrine sediment samples, 5 alluvial sediment samples and 19 bedrock samples were examined in this study. First, aeolian sand samples were classified into several groups by assemblage-based hierarchical cluster analysis. Then, the mineralogy of each group was compared with potential source mineralogies to determine the groups’ origins. Finally, the dune sands’ transport pathways were determined by comparing the between-assemblage similarities of sands along the wind direction. The results reveal the following: (1) The aeolian sand heavy-mineral suites in the central and northern areas differ from those in the southwestern areas, suggesting significant source differences. In the central and northern areas, the weathered detritus of sandstone was concentrated in depressions mainly by fluvial processes, thus providing a primarily fluvio-lacustrine sediment supply for dune creation. In the desert’s southwestern region, the sources also include Yellow River sediment and Loess Plateau slopewash. (2) The sand transport is strongly limited by fluvial and lacustrine systems, leading to anisotropic suite patterns in aeolian sand in the Mu Us Desert.