中国东部海域表层沉积物粒度组成及影响因素

基于海洋区域地质调查获取的1 438个粒度数据，利用Folk分类方法将中国东部海域表层沉积物划分为砂质粉砂、粉砂质砂、粉砂、砂、砂质泥、泥质砂、泥7种沉积物类型，阐述了不同沉积物类型的粒度组成和参数特征.其中，砂质粉砂、粉砂质砂和粉砂是3种最主要的沉积物类型，分别占样品总数的34.70%、24.20%和15.51%.粉砂质砂呈条带状分布在研究区的南部且向北延伸.粉砂主要分布在长江口-浙闽沿岸、渤海西部和南黄海中北部.砂主要分布在东海外陆架、扬子浅滩和苏北浅滩、朝鲜湾等海区，其中在东海外陆架海区分布最广.影响沉积物分布的主要因素有物源、水动力环境以及水深、地形、地貌等.晚第四纪冰期旋回中海平面变化和海洋环流控制陆源沉积物的入海通量和陆架沉积体系的发育过程.综合沉积物物源供给、海洋环流、冰后期海平面变化过程，基于Folk分类的动力学属性和表层沉积物类型分布，将中国东部海域表层沉积物分布划分为河口沉积、陆架泥质沉积、潮流沉积以及残留沉积等分区.不同沉积分区的形成机制和影响因素差异显著，反映出在中国东部陆架的特殊地形影响下，不同海平面时期陆源碎屑物质的运移过程. 

Grain Size Compositions and Their Influencing Factors of the Surface Sediments in Eastern China Seas

Based on 1 438 grain size data obtained by marine regional geologic survey, surface sediments of the eastern China Seas are divided into seven types including sandy silt, silty sand, silt, sand, sandy mud, muddy sand and mud by Folk nomenclature.Meanwhile, the grain size features and their parameters are well described.Among them, sandy silt, silty sand, and silty sand are the three main sediment types, accounting for 34.70%, 24.20% and 15.51% respectively.The distribution of silty sand is strip-shaped in the south area.Silty sand is mainly distributed in Zhejiang and Fujian coastal zones, the western Bohai Sea, the central and northern areas of the southern Yellow Sea.Sand is mainly distributed on the East China Sea shelf, Yangtze Shoal, Subei Shoal and western Korea Bay.The influence factors of the sediments distribution include provenance, hydrodynamic environment, water depth, topography and geomorphology, etc. The sea level changes and ocean circulations during the Late Quaternary control the sediment flux into the seas and the sedimentary system on the shelves.Based on the dynamic properties of Folk classification and the type distributions, four kind of sedimentary areas are mainly identified in the eastern China Seas, such as estuarine deposition areas, shelf muddy deposition areas, tidal deposition areas and residual deposition areas.The formation mechanism and influence factors of different sedimentary areas are significantly different, which reflects the process of clastic sediment migration with the sea level changes affected by the special topography of the eastern China Seas.