粤西水东湾现代沉积环境特征与泥沙搬运路径

CHARACTERISTICS OF MODERN SEDIMENTARY ENVIRONMENT AND SEDIMENT TRANSPORT PATTERNS IN SHUIDONG BAY, WESTERN GUANGDONG

对粤西水东湾沉积地貌单元的现代沉积物分布特征分析与泥沙净搬运矢量计算表明，滨面斜坡沉积物主要由砂粒级物质组成，粒级参数Ｍｄ，ＱＤ和ＳＫ具有从海向岸、自东向西变化的总趋势，泥沙净搬运趋势以向岸和西北为主。落潮三角洲沉积物较其邻近滨面斜坡有所粗化，分选从中部向两侧变好，泥沙在落潮流与波浪驱动下沿落潮三角洲边缘向西运动。口门内潮汐通道深槽泥沙净搬运趋势指向湖。湖区的沉积物以泥质为主，分选中等至差，并形成绕涨潮三角洲的泥沙环流元。

This paper analyzes the surficial sediment distribution characteristics of the sedimentary morphology units and computes the sediment net transport vectors. The results show that the sediments in the shoreface ramp are mainly composed of sands, and grain size parameters (Md, QD and SK) distributions characterize the overall trends which regularly change from the sea to the shore and from the east to the west. The sediments in the ebb delta are coarser than those in its adjacent shore face ramp and the sorting coefficients decrease from the middle part to both sides. The sorting of sediments in the lagoon which are sandy clay is from medium to poor.By using computed results of a sediment transport vector model, the sediment transport patterns in Shuidong Bay indicate that the sediments in the shoreface ramp generally transport shoreward and northwestward. The sediments in the ebb delta which are driven by waves and tidal currents transport westward along the delta edge. The net transport trending of the sediments in the tidal channel within the channel mouth is towards the lagoon. The sediment transport in the lagoon forms a circulation cell around the flood delta. The present deposition center of the lagoon locates in the eastern part of the lagoon.