响水河中游右岸沙丘群粒度分布特征

在野外实地考察和测量的基础上，沿盛行风向，对西辽河平原西部响水河中游右岸普遍发育的新月形沙丘链进行样品采集。经室内激光粒度仪测定，研究了河岸沙丘粒度分布规律。结果表明：（1）响水河右岸沙丘及丘间地以中沙为主，而河谷谷底细沙含量最多，平沙地次之。（2）滨岸沙丘由迎风坡脚到丘顶平均粒径变小，远岸沙丘由迎风坡脚到丘顶平均粒径变大；多数沙丘分选性由两侧坡脚到丘顶变好；多数沙丘丘顶偏度值和峰态值大于两侧坡脚。（3）滨岸沙丘受风、水两相作用，能从较深地层获得沙源；其下风向沙丘主要受风力作用，沙源主要为丘间地沙及上风向风沙流携带的较细沙。

Grain Size Characteristics of sand dunes on the Right Bank of the Middle Xiangshui River

Ninety four samples from surface of typical barchans chains on the right bank of the mid-Xiangshui River in the Xiliaohe Plain were collected along the prevailing wind direction. Distribution law of grain size was studied by Laser particle analyzer. Combining with field observation, the results were obtained as follows: (1) The sand dunes and interdunes on the right bank of the mid-Xiangshui River are mainly composed of medium sand, and it is fine sand for that in the bottom of valley. (2) The grain size of dunes adjacent to the valley appears thinner from stoss toe to the summit, while the grain size of dunes away from valley appears coarser from stoss toe to the slope top. The sorting becomes much better from both upwind and downwind toes to the dune tops. The skewness and kurtosis of sediment on the tops of dune are primarily larger than on the toes. (3) Due to the aeolian-fluvial interactions, sand dunes near valley can obtain rich sand source from underlying strata. However, downwind dunes acquire sand from interdunes and drifting fine sand by wind.