陕西红碱淖湖底表层沉积物粒度特征

根据不同沉积环境的代表性和空间分布的均匀性原则，对陕西北部红碱淖湖泊表层沉积物进行了较为系统的采样和粒度分析。粒度分析结果显示，红碱淖湖泊表层底泥主要由三种沉积类型组成：湖心稳定的湖泊沉积、受入湖河流影响的河口及三角洲沉积、相对稳定的近岸沉积。粒度分布的多组分特征不仅指示了沉积物来源差异，还指示了其环境和沉积动力。平均粒径的空间分布特征可以指示湖泊底流的流向及动力特征。发现西部湖盆目前仍受入湖径流的影响，而东部湖盆则受入湖径流影响相对较弱。粒度揭示的湖泊底流特征，可以作为研究入湖污染物及其扩散规律的依据之一。

Grain-size characteristics of the surface deposit in Hongjiannao Lake in northern Shaanxi Province

In this paper, the surface deposit from Hongjiannao Lake, the biggest desert lake in China, was systematic sampled and performed grain size analysis. The result shows that there are mainly three types of deposit in Hongjiannao Lake: (1) the deposit in a stable depositional environment around the lake centers, (2) delta deposit in the estuarine area, and (3) deposit in a relatively stable depositional environment near the lakeshore. The multimodal characteristics of grain size distribution of the samples from the Hongjianao Lake not only indicate the sources of the deposit but also indicate its depositional dynamics. The spatial distribution of the mean grain size of the samples can be used for tracing the direction of the bottom current. The isoline map shows that the affection of river on the grain size of the surface deposit in the west lake basin is relatively stronger than that in the east lake basin. Based on these results, the authors further point out that the bottom current as inferred by the spatial distribution of mean grain size is of importance in the study on the movement law of pollutant diffusion in the lake.