Experimental analysis of dust deposition and physical weathering intensity in the Gobi Desert

Surface soil materials from the Gobi Desert were sieved into fraction groups of 0.063–0.125, 0.125–0.25, 0.25–0.5, 0.5–1, and 1–2 mm. These samples were placed in a field for a physical weathering and dust deposition experiment. In the natural Gobi Desert environment, the dust-sized fractions (< 0.063 mm in diameter) produced by physical weathering and via dust deposition in the above groups were 1387 ± 124, 702 ± 70, 698 ± 47, 742 ± 101, and 769 ± 75 gm⁻², respectively, from 18 October 2020 to 18 December 2021. Dust deposition during the same period was 611 ± 55 gm⁻². For the same respective groups, 5.32 ± 0.76%, 0.58 ± 0.27%, 0.53 ± 0.18%, 0.80 ± 0.52%, and 0.98 ± 0.31% (by weight) of the bulk samples were weathered into dust-sized fractions during the experimental period. The physical weathering intensities were 23.95%, 14.96%, 8.90%, and 2.81% by weight for fraction groups of 2–4, 4–8, 8–16, and > 16 mm, respectively. The fine-grained materials of the gravel were more sensitive to physical weathering than coarse materials. In natural environments, the processes of dust deposition and physical weathering were key factors affecting the surface topographical equilibrium of the Gobi Desert and dust emission in Asia.