汕尾市品清湖是我国目前最大的沿岸泻湖, 作者首次对其进行了实地精确测量, 面积为23.16km2, 湖岸线长39.62km。前人对品清湖的研究认为品清湖潮汐类型属于混合潮中的不正规日潮型, 本文测量计算潮汐系数F为1.1，认为该区域的潮汐类型属于混合潮中的不正规半日潮型, 分析研究品清湖的沉积环境特征对研究我国沿岸泻湖的形成演化具有典型的示范意义。本文通过对品清湖水文动力、泥沙运移、沉积年代的研究, 在对品清湖地质背景、形成演化过程、地形地貌特征、环境动力特征等分析的基础上, 对47个表层沉积物样品进行了粒度组分等分析, 全面了解品清湖沉积物的类型、粒度组成及特征, 沉积物分布、分区及来源等沉积环境特征。分析结果显示品清湖沉积物主要由黏土、粉砂、砂以及砾石组成, 沉积物类型可以分为黏土质粉砂、砂质粉砂、粉砂质砂、砾质砂、砂质砾、砂—粉砂—黏土以及砂等7个类型, 其中黏土质粉砂是品清湖的主要底质类型。沉积物的来源有多源性或受多种动力因素影响, 主要有4种来源, 具有典型泻湖港湾沉积的特点, 品清湖的底质分区可划分为6个区域, 不同的区域反映了不同的物质来源和动力环境。

The Pinqing Lake with an area of 23.16 km2 and a length of 39.62 km along the coast is located in Shanwei City of southern China; it is the biggest coastal lagoon in China. Previous studies suggested that the tide type in the lake belongs to irregular diurnal tide within the hybrid tides. In this paper, the authors calculate the tide coefficient 1.1 and suggest that it belongs to irregular semidiurnal tide based on their measurements and calculations. Analysis of the Pinqing Lake's sedimenta-tion environment is a typical example to study the evolution of lagoons in the coastal area. The hydrodynamics, transportation of various sediments and the chronological study of the sedimentations are presented in this paper. Combining the under-standing of the geological background, evolution processes and geomorphologic features of lagoon systems, particle compo-nents of 47 surface sediment samples from the Pinqing Lake are obtained and analyzed. The sediment types, grain size com-ponents, sediment sources and distributions, sedimentary environments and zonation of the Pinqing Lake are fully investigated. Analysis results suggest that sediments from the Pingqing Lake are mainly composed of clay, silt, sand, and gravels. A total of seven types of sediments are identified, including clayey silt, sandy silt, silty sand, gravel sand, sandy gravel, sand-silt-clay, and sand. The main type of the sediment in the Pinging Lake is clayey silt. The sediment is from different sources, and is con-trolled by different driving mechanisms. The results suggest there are four different sources with typical lagoon sedimentation. The Pinqing Lake is divided into six different zones according to sedimentary features, and different sedimentary regions in-dicate different sediment origins and dynamic environments.