Abstract:

To study the sediments grain size characteristics and sedimentary environment of different gobi types at the periphery of Badain Jaran Desert， this paper analyzed the grain size characteristics of sediments and sedimentary environment from different gobi types based on the grain size measurements and the classification of Gobi types， the surface layer and underlying layer sediment samples were collected around the desert at August 2023 year in 41 gobi sample sites. The results show that： on the profile， the sediments of each gobi are poorly sorted， and the grain sizes are in a multimodal state. since the transition from coarse gravelly gobi to fine-grained gobi， the proportion of gravel in the surface sediment decreases， the proportion of sand increases， and the proportion of silt+clay shows a trend of decreasing and then increasing； on the profile， the proportion of silt+clay in the surface layer is lower than that in the underlying layer， and the proportion of gravel and sand is higher in the surface layer than that in the underlying layer. The sediments in the underlying layers of each gobi were formed in alluvial and fluvial depositional environments， and the surface sediments of the medium-gravelly gobi and fine-gravelly gobi are characterized by aeolian deposition. The results provide basic data for the gobi regional ecological environment construction and desertification control．

Key words: grain size, sedimentary environment, gobi, Badain Jaran Desert