塔克拉玛干沙漠沙丘沙和大气降尘粒度分异特征

Grain Size Differentiation of Dune Sand and Atmospheric Dustfall in the Taklimakan Desert

基于粒度特征区分风尘序列中沙尘暴降尘和流动沙丘沙组分对探究环境演变、重建风尘活动强度有重要意义。以塔克拉玛干沙漠中部流动沙丘沙和沙漠南缘策勒绿洲现代大气降尘为研究对象,分析粒度差异,并与中国其他地区沙丘沙进行对比。结果表明:(1)塔克拉玛干沙漠沙丘沙粒度曲线以单峰分布为主,策勒绿洲尘暴降尘呈双峰分布;(2)塔克拉玛干沙漠沙丘沙和降尘均呈分选较好、近对称分布和中等峰态,但沙丘沙粒径粗;(3)不同区域沙丘沙的相同粒径组分相对含量和粒度特征具有相似性。尽管沙丘沙和大气降尘均有较好的分选性,但风场强度的差异导致粒径分布范围、偏态和峰度不同。

Grain size serves as a pivotal method to differentiate sand dunes from storm dustfall,with significant implications for understanding environmental changes and reconstructing historical aeolian activities.Samples of dune sands from the center of the Taklimakan Desert and the storm dustfall from the Cele Oasis,situated at the southern edge of the desert,were collected to analyze their grain size characteristics.Subsequently,a comparative analysis was conducted with dune sands sourced from various regions across China.The results indicated that:(1)The particle size distribution curves of dune sands in the Taklimakan Desert mainly exhibits unimodal distributions,while storm dustfall from the Cele Oasis exhibits bimodal distributions;(2)Both dune sands and storm dustfall in the Taklimakan Desert demonstrate well sorting,nearly symmetrical distributions,and moderate kurtosis,with dune sands exhibiting coarser particle sizes;(3)The relative content and particle size characteristics of identical particle size components of dune sands in different regions of China exhibit similarities.Despite the well sorting of both dune sands and atmospheric dustfall,differences in wind field intensity lead to variations in their particle size distribution ranges,skewness,and kurtosis.The findings of this study can provide a basis for distinguishing aeolian components within geological formations at desert fringe regions.