黄河乌兰布和沙漠段不同区域入黄沙物质粒度特征及其来源分析

土壤是具有自相似结构及一定分形特征的不规则复杂多孔介质,为更好地对黄河乌兰布和沙漠段不同区域入黄沙物质粒度特征进行定量表征并解析其来源,利用传统统计学和多重分形理论,研究了黄河乌兰布和沙漠不同地段土壤的粒度特征及粒径分布。结果表明:研究区土壤颗粒组成具有明显的多重分形特征,沙头对岸D_0值为0.821、D_1值为4.386,即粒径分布范围最宽且最不均匀,荒漠草原D_1值为2.970、D_1/D_0值为4.595,即粒径分布最均匀且离散程度最大;不同地段土壤粒径分布范围间存在差异,但相近地段颗粒组成类似;河道左岸由于受乌兰布和沙漠的影响,使得河道左侧的沉积物粒度变粗,其来源于沙漠的沙物质,而右侧河道几乎不受乌兰布和沙漠的影响。

Grain size characteristics and source analysis of aeolian sediment feed into river in Ulanbuh Desert along bank of Yellow River

Soil is a kind of irregular and complex porous media with self-similar structure and certain fractal characteristics. In order to quantitatively characterize the grain size characteristics and analyze the source of sediment in different areas of Ulanbuh desert along bank of the Yellow River,the grain size characteristics and particle size distribution of soil in different areas were studied by using traditional statistics and multifractal theory. The results show that the soil particle composition has obvious multifractal characteristics. The D₀ value of the opposite bank of sand head is 0.821,and the D₁ value is 4.386,which means that the distribution range of particle size is the widest and most uneven. The D₁ value of desert grassland is 2.970,and the D₁/D₀ value is 4.595,which means that the distribution of soil particle size is the most uniform and the degree of dispersion is the largest. Due to the influence of Ulanbuh desert on the left bank of the river channel, the grain size of the sediment on the left side of the river channel is coarser, which comes from the sand material of the desert,while the river channel on the right side is hardly affected by the desert.