河西走廊新月形沙丘表层沉积物的理化性质

Physicochemical Characteristics of Surface Sediments of Crescent-shaped Sand Dunes in the Hexi Corridor,Gansu,China

沙丘表层沉积物的理化特征是风沙地貌研究的重要内容。选取了河西走廊沙漠中部戈壁地表发育的新月形沙丘、灌丛沙丘及附近的湖相沉积物和戈壁表层沉积物的38个样品,对其物理性质(平均粒径、分选程度、峰度、偏度)和化学性质(常量元素和微量元素)进行分析。结果表明:河西走廊新月形沙丘表层沉积物粒度以中沙为主(21.65%～57.39%),其次是细沙(23.22%～52.96%);平均粒径为0.27～0.43 mm,大于其他沙漠。分选性以中等较好为主,粒度曲线近对称,峰度中等。常量元素以CaO和SiO2为主,分别为5.55%和66.12%;微量元素含量在同一沙丘具有相似性,但不同的沙丘之间的含量有所差异。

The physicochemical characteristics of aeolian sediments in sand dunes surface is one of the important issue in aeolian geomorphology. The 38 surface sediment samplers had been selected from the crescent-shaped sand dunes,vegetable dunes and lacustrine sediments at the gobi surface in the middle desert of the Hexi Corridor. The physical properties( average particle size,sorting degree,kurtosis,skewness) and chemical properties( major and trace elements) of these sediment samples were analyzed. The results showed that the surface sediments of crescent dunes in Hexi Corridor are mainly of medium sand( 21. 65%-57. 39%),followed by fine sand( 23. 22%-52.96%). The averaged particle size is 0.27 ~ 0.43 mm and larger than other deserts. The sediments from dunes are moderately well sorted and with a near symmetry and mesokurtic distribution. The major elements are mainly Cao and SiO 2,5.55% and 66.12%,respectively. The content of trace elements is similar in the same dune,but the contents are different for different dunes.