【摘要】 戈壁地表沉积物组分呈多峰态分布的特征,研究其全粒径分布模式是认识戈壁成因及形成过程的基础。目前粒度分布模式（对数正态分布、Weibull分布等）难以正确表达呈多峰态的沉积物粒度分布特征,本文利用单调递减函数P（d_i）=Cd_i^-μexp（-d_i/Dc）,对戈壁地表沉积物粒度的全粒径分布模式进行解析。结果表明:（1）该函数能够反映出戈壁地表沉积物组分的全粒径分布特征,拟合优度R²>0.99,参数C值范围为52.64～166.75,μ为-0.083～0.108,Dc为0.103～2.336;（2）在分选作用下,以富沙组分为主的戈壁地表,跃移组分含量高,μ值、Dc值偏小,以富砾组分为主的戈壁地表,蠕移及风蚀残余组分含量高,μ值、Dc值偏大;（3）全粒径分布模式参数值可以揭示洪积扇戈壁的分选沉积特征,为解析戈壁地表的成因以及风蚀风积作用提供新的指标参数。更多还原

【Abstract】 Studying particle size distribution models is the basis for understanding the formation process of gobi.However, the frequency distribution of surface sediment components in gobi desert are characterized by multimodal,and the general particle size distribution function with Log-normal or Weibull distribution are difficult to be used to correctly express the particle size distribution characteristics of sediments with multimodal. Therefore, this study was designed to analyze the particle size distribution of the gobi surface sediments using the monotonicaly decreasing function P（ d_i） =Cd_i^-μ exp（-d_i/Dc）. The results showed that this function was able to reflect the particle size distribution characteristics of gobi surface sediment components with the goodness of fit as R² >0.99. The range of parameter C was 52.64-166.75, μ was 0.083-0.108, and Dc was 0.103-2.336. Under the effect of sorting, the components for jumping movement was large with relatively small μ and Dc values in sand-rich surface of gobi. The residual components for wind-induced erosion and creep movement was large with relatively large μ and Dc values in gravel-rich surface of gobi. The parameters using particle size model can reveal the sorting sedimentary characteristics of alluvial fan gobi and provide a new indicating parameter for analyzing the formation process of gobi surface and the wind-induced erosion.更多还原