桑沟湾海域表层沉积物粒度特征及其环境意义

Grain-size distribution of surface sediments in Sanggou Bay and its environmental significance

根据桑沟湾和邻近海域201个表层沉积物样品粒度测试结果,分析了砾、砂、粉砂和黏土等各粒级组分含量分布特征,划分了沉积物类型,探讨了沉积环境。结果表明,沉积物组分中以粉砂粒级组分为主,砾和砂分布相对集中。海域表层沉积物类型共有12类,含砾沉积物类型7类,不含砾沉积物类型5类,其中砂质粉砂与粉砂分布最广。桑沟湾及邻近海域沉积物分布主要受控于泥沙来源、地形地貌及潮流、波浪、沿岸流等沉积动力条件的共同作用。桑沟湾西部近岸海域的泥沙为近源沉积,颗粒较粗,向海扩散有限;桑沟湾外沉积物颗粒由东向西变细,与黄海西部沿岸流携带的黄河源泥沙向西扩散有关;桑沟湾内沉积物颗粒较细,水动力较弱;桑沟湾东北部和东南部海底的脊状凸起区域,含砾沉积物为当地近源碎屑沉积,受海流冲刷的影响,细颗粒碎屑难以沉积。

The characteristics of grain size distribution on 202 surface sediment samples in Sanggou Bay and adjacent area was analyzed,from which the distribution patterns of gravel,sand,silt and clay were specified,the sediment types were divided,and the sedimentary environments were discussed.Results show that the sediment composition is mainly silt,and the distribution of gravel and sand content is relatively concentrated,and there are 14 types of surface sediments in Sanggou Bay and adjacent area,including 8 types with gravels and 6 types no gravels,and sandy silt and silt are most widely distributed.The distribution of sediments in Sanggou Bay and adjacent area is mainly under the control of sediment supply,landforms,tidal currents,waves,and coastal currents.The sediments near shore in the western of Sanggou Bay is coarse and near the source area with limited seaward dispersion.The sediment particles outside Sanggou Bay become finer from east to west,which is related to the westward diffusion of sediment from the source of the Yellow River carried by the coastal current along coast of the western Yellow Sea.The sediment particles of inner Sanggou Bay are fine and the hydrodynamic force is weak.The gravel-bearing sediments in the seafloor ridge area of northeast and southeast of the Sanggou Bay are local near-source clastic sediments,and the fine particles are difficult to deposit because of scouring by the ocean currents.