Provenance of surface dune sands in the Gurbantunggut Desert, northwestern China: Qualitative and quantitative assessment using geochemical fingerprinting

Understanding the relationship between sand sources and sinks in deserts can provide valuable insights into the dynamics governing the formation of desert dunes. Despite attempts to elucidate the material origins of the Gurbantunggut Desert, uncertainty persists, particularly regarding the quantitative source contributions across various particle size fractions. To address this issue, we conducted a comprehensive analysis of the geochemical composition (trace and rare earth elements) within the coarse (75-250 mu m) and fine (<75 mu m) fractions of 20 surface dune sand samples from the Gurbantunggut Desert. Employing multidimensional scaling (MDS) and sediment source fingerprinting (SSF), we identified the main sources for both coarse and fine fractions of the dune sands, and calculated the relative contributions from three potential sources associated with the Altai, Tianshan and Junggar Mts. Our results reveal spatial heterogeneity in the provenance of dune sands within the Gurbantunggut Desert. Sands from the central and eastern regions of the desert primarily originate from the Altai Mts., while those from the western part of the desert are primarily sourced from the Junggar Mts. This sourcesink relationship aligns with the prevailing wind patterns in the Junggar Basin-that is, the upwind Altai and Junggar Mts. function as significant sediment sources for the downwind desert areas. This highlights the crucial role of wind patterns in determining the sand sources in the Gurbantunggut Desert. Our findings suggest that desert formation depends not only on sufficient sand material, but also on the availability and mobility of sand, which is largely influenced by regional wind patterns.