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对2007年采自越南红河水下三角洲北区24个表层沉积物样品进行了粒度分析和粒度参数计算,初步探讨了该区沉积物的主要类型及分布特征。结果表明,越南红河水下三角洲北区的表层沉积物主要由粉砂组成(体积平均含量为54.35%),平均粒径为6φ。按Link沉积物命名法,该区沉积物主要类型有砂、砂质粉砂和黏土质粉砂。水平分布上,由西部的砂向东逐渐变为黏土质粉砂,呈现出由近岸三角洲前缘相的粗粒级沉积物逐渐向前三角洲-浅海相的细粒级沉积物变化的趋势。与前人研究成果对比发现,红河水下三角洲北区沉积物黏土的比例较1996年的比例明显增大,可能与海岸线近10a来总体上呈向陆迁移、水下三角洲沉积向岸蚀退以及纵向上水动力逐渐变弱有关。
The grain size and particle size parameters of 24 surface sediment samples taken from the northern part of the Honghe subaqueous delta of Hong Kong in 2007 were calculated and the main types and distribution characteristics of the sediments in this area were discussed. The results show that the surface sediments in the northern part of Honghe subaqueous delta of Vietnam mainly consist of silt (volume average content is 54.35%) and the average particle size is 6φ. By Link sediment nomenclature, the main types of sediment in this area are sand, sandy silt and clay silt. In the horizontal distribution, the sand from the west to the east gradually changes into clay silt, showing a tendency of fine-grained sediments gradually changing from the coarse-grained sediments of the nearshore delta front to the delta-shallow marine facies. Compared with the previous research results, it is found that the proportion of clay in the sediments in the northern part of the Honghe subaqueous delta obviously increases compared with that in 1996, which may be shifted to the mainland as a whole with the coastline nearly 10 years, ebb and flow backward in the subaqueous delta Longitudinal hydrodynamic weakening related.