Abstract:  In this study, the multi-fractal theory was used to analyze the sand particle size of land surface sediment so as to demonstrate the variation of wind-induced sand sedimentary environment along both banks of the Ulanbuh Desert reach of the Yellow River and the sand source region on the east bank. Results showed that the sand particle size ranged from 189.13 to 212.20 μm on the west bank and from 133.89 to 168.56 μm on the east bank, which indicated that the surface particle size was finer and the wind energy was weaker on the west bank than those on the east bank. Multi-fractal spectrum parameters D₀, D₁, D₂,?α, and?f for the east bank were higher than those on the west bank, the particle size range on the east bank was wider than that on the west bank, and the local sediment particles on the east bank were more overlapped than those on the west bank, which further demonstrated the significant differences of the particle properties of sediment, wide range of particle sources, complex sedimentary process and diverse sedimentary environments on the east bank. There were the significant correlations among the parameters mentioned above and the contents of particle sizes ranging from 2 to 50 μm and 100 to 250 μm. According to the wind-induced sand migration law and the landforms on both banks, it was preliminarily revealed that the upwind Ulanbuh Desert was one of the main source regions of 2-50-μm suspended sand particles over the east bank of the Yellow River. 

Key words: sediment; particle size, multi-fractal parameter, sedimentary environment, Ulanbuh Desert; Yellow River