长江河口表层沉积物输移特征分析

摘要

Cluster analysis and Gao-Colliins particle size trend analysis model will be used in sediment characteristics and transport of Yangtze Delta 948 surface sediment samples.The results showed that:Changjiang Estuary sediments can be divided into three categories.The first class of sediments composed mainly of silt,these are mainly distributed in the Yangtze Delta southeast 1 0 m depth contour to 40 m iso-bath range.The second category mainly silty sediment sand,sandy silt,mainly distributed in the waters east of Qidong between 20 to 40 m bathymetric contour.Yangtze River estuary sediment transport in the overall trend can be broadly divided into two directions toward the estuary of northeast and the coast of south.North branch of the Yangtze River near the exit of the sediments have a tendency to transport with-in the estuary.North branch of estuary sediments isobath 20 ~40 m between the transport to the north-east.Southern branch outlet affected runoff,coastal streams south transport part,the other part shelf sea-ward transport and counterclockwise turn to the northeast in the 1 0 m isobath sediment transport trends section,in the northeast corner of the study area there is transport to the estuary of the trend shelf.%基于聚类分析和 Gao-Colliins 粒径趋势分析模型对长江口948个表层沉积物样品的特征及输移进行研究，结果表明：长江口表层沉积物的变化可划分为3类：第一类沉积物以粉砂为主，主要分布在长江口外东南方向10～40 m 等深线以浅区。第二类沉积物主要以粉砂质砂、砂质粉砂为主，主要分布在长江口苏北沿岸以东海域20～40 m 等深线之间。第三类沉积物以细砂、中细砂为主，分布区域主要在苏北沿岸地区。长江口外沉积物整体的输移趋势大致可分为沿岸向南和朝口外偏东北两个方向。长江北支出口附近沉积物有向河口内输移的趋势，北支口外20～40 m 等深线之间有来自苏北沿岸、外海陆架的来沙在此汇聚后转向东北方向输移。南、北港口外受径流、沿岸流的影响大部分沿岸向南输移，另一部分向外海陆架输移，并在10 m 等深线处部分泥沙输移趋势逆时针偏向东北，在研究区域东北角存在有陆架向河口的输移趋势。