阿拉善高原东南部干涸湖盆沉积物粒度特征

干涸湖盆是西北干旱区广泛分布的地貌类型，也被认为是重要的沙尘源区，但目前对该类地表的土壤风蚀过程与特征研究较少。干涸湖盆沉积物和植被盖度的空间差异性导致沙尘释放过程和风蚀过程具有时空差异性。为了探讨干涸湖盆的土壤风蚀特征，选择阿拉善高原东南部的干涸湖盆为研究区域，沿主风向（西北-东南）方向，选择4个区域，野外实地收集湖相沉积物和灌丛沙丘样品，进行粒度特征分析。结果表明：（1）干涸湖盆地表沉积物粒度存在明显的空间差异性，一方面反映了物源的差异性，另一方面反映了风蚀过程的差异性。（2）受植被和风程长度的影响，上风向和下风向风蚀较弱，而中部地区风蚀最大。

Sediment grain size characteristics at extinct lakes in the south Alxa， China

The extinct lakes are widely distributed in the arid region of the north China， which also are the important dust sources. However， there are just few studies on its wind erosion processes and characteristics. Land surface deposits and vegetation coverage caused the spatial and temporal difference of the dust emission processes and wind erosion processes. To explain the wind erosion processes at the extinct lake， four different areas at the extinct lake in the south region of the Alxa Plateau were selected as study regions， and sediment grain-size parameters were analyzed. The results indicate that （1） Sediment grain size parameters have obvious spatial difference， which explain the difference of sediment provenance and wind erosion processes. （2） Basin on the grain size parameters analysis， wind erosion is weaker in the upwind and downwind regions， and strong in middle region.