毛乌素沙地西南缘灌丛沙丘沉积物的粒度和元素特征

对毛乌素沙地白刺(Nitraria tangutorum)灌丛沙丘沉积物粒度和元素特征进行了采样分析.结果表明:灌丛沙丘沉积物来源单一,几乎全部由丘间地物质组成,其粒度和元素特征与丘间地物质极其相似;相对而言,灌丛沙丘沉积物比丘间地物质含有更多粗颗粒物,主要因丘间地可做跃移运动的中沙和细沙更易被灌丛阻挡而堆积;灌丛沙丘沉积物中大部分元素含量比丘间地物质低,主要因这些元素易被淋溶迁移到丘间地富集;灌丛沙丘发育以来,虽然其沉积环境存在波动,但相对稳定,未发生过显著变化.

The Characteristics of Grain Size and Chemical Elements of the Nebkha Sediments in the Southwestern Margin of the Mu Us Sandy Land

The characteristics of grain size and chemical elements of the Nitraria tangutorum nebkha sediments in the Mu Us Sandy Land have been analyzed. The results show that the nebkha sediments almost all come from the surface soils at the interdune, and its characteristics of grain size and chemical elements are extremely similar to that of the surface soils at the interdune. Comparatively, the nebkha sediments contain more coarse particles than the surface soils at the interdune, which is mainly because the medium sand and fine sand that can be transported by saltation easily are intercepted by nebkha and then accumulate. The contents of most chemical elements are lower in the nebkha sediments than in the surface soils at the interdune, which is mainly because the elements easily enrich in the surface soil at the interdune due to the leaching and movement. Since the development of the nebkha, the sedimentary environment of the nebkha has fluctuated but relatively been stable with few significant changes.