对福建平海-浮叶海域878个站位的表层沉积物样品进行粒度测试与统计分析，结果表明研究区表层沉积物粒度介于黏土和砾石之间，按照福克粒度命名法可分为14种类型。其中，粉砂分布最广，砂质粉砂次之，二者共占70%以上。近岸湾内水域和远岸开阔海域水动力条件相对较弱，沉积物粒度相对偏细，多分布粉砂和砂质粉砂；南日水道和兴化水道两侧海域水动力条件较强，沉积物的粒度较粗，由砂和含砾沉积物组成。这种分布格局受研究区物源、水动力条件、海底地形等因素的共同控制，推测物源主要为木兰溪带来的陆源碎屑物，水动力环境受闽浙沿岸流、潮流和波浪的共同影响。值得注意的是南日水道和兴化水道为潮流通道，但底质沉积物较细，广泛分布着粉砂和砂质粉砂，推测是由于本区的水道接近均衡状态，水动力条件减弱，致使细粒的物质沉积下来。%Grain size measurements and statistical analysis have been carried out for the surface sediments of 878 stations collected from Pinghai-Fuye sea of Fujian Province.The results show that there are 14 types of sediments varying from clay to gravel,according to Folk descriptive terminology.Sediments are dominated by Silt,and silt and sandy silt constitute 70% of all the samples.Alterative hydrodynamic con-ditions result in different grain-size distributions in the study area,i.e.,weak hydrodynamics corresponds to silt and sandy-silt in the areas of coastal bay and offshore area,while coarser sediments,e.g.,sand and gravel,are attributed to strong hydrodynamics occurring at both sides of Nanri channel and Xinghua chan-nel area.Factors including sediment source,hydrodynamic condition and submarine topography,affect the grain-size distribution in the study area.The sediments in study area are probably loaded by the Mulan River.The sedimentation process is influenced by Min-Zhe coast current,tide and wave.It is note that, both of the Nanri channel and Xinghua channel are tidal channels,but the surface sediments in the chan-nels are dominated by silt and sandy silt.We suggest that the hydrodynamics in the channel may be close to a balanced status,resulting in a relatively quiet environment where the fine materials could deposit.
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