Distribution on Surface Sediment and Sedimentary Divisions in the Middle Part of Bohai Sea

Key words: 
• surface sediment type /
• grain size characteristic /
• sediment division /
• the middle part of Bohai Sea

Abstract: To understand the relationship of distribution characteristic of surface sediment with the sediment supply and the hydrodynamic environment in the middle part of Bohai Sea, 1448 surface sediment samples were selected densely. Some grain size characteristics of the surface sediment sample were analyzed. The results indicate that ten different sediment types were recognized in the studied area, such as gravel, sandy gravel, gravelly sand, sand, silty sand, sandy silt, silt, clayey silt, sandsiltclay and silty clay. Among these ten sediment types, silty sand and clayey silt distribute most widely, while the gravel and silt lesser. The sediment divisions in the middle part of Bohai Sea are composed of Laotieshan Channel, Bozhong Shoal and Liaodong Shoal, Bozhong Plain, Bohai Bay Plain and Western Bohai Gradient Plain. After entering into Bohai Sea, the residual Yellow Sea Warm Current evolves into Bohai Sea Circumfluence, which dominates the pattern of sediment distribution in the middle part of Bohai Sea, and Bohai Strait strong tidal current, Liaodong Bay Circumfluence and Laizhou Bay Circumfluence also play a important role in controlling the sediment distribution pattern. And then the "in north and out south" pattern of sediment exchange is formed, resulted from these dynamic conditions.