关键词: 库姆塔格沙漠, 粒度特征, 成因与环境

Abstract: Kumtag desert located at the northwest arid area of China is known as the sixth largest desert of China. Method of grain size analysis plays important role in sedimentary environment differentiation，hydrodynamic condition distinguishing, and grain size trend analysis, etc. Analyzing results to 20 sand samples taken from middle-northern, north margin, western, middle and southern, southeast margin of Kumtag Desert show that there are remarkable differentiation in grain-size distribution, and the mean parameters are as follows: median diameter Mz=1.55~2.92 Φ, the standard deviation σ1=0.41~1.11, skewness SK1=-0.11~0.31, kurtosis KG=0.77~1.23. The grain size frequency curves of the samples have characteristics of single peaks or multi-peaks; most of the sand skewness is nearly symmetric. The analytical results reveal that the sediments in Kumtag Desert are complex and diverse, having aeolian, lacustrine and alluvial（proluvial）sediments river and so on.

Key words: Kumtag Desert, characteristic of grain size, formation and environment