渤海中部表层沉积物分布特征与粒度分区

为了解渤海中部海区表层沉积物分布特征与物质来源和水动力环境的关系,高密度采集了海区1448个表层沉积物样品,并进行粒度参数的相关分析。结果表明,研究区表层沉积物类型主要有砾石、砂质砾、砾质砂、砂、粉砂质砂、砂质粉砂、粉砂、黏土质粉砂、砂-粉砂-黏土和粉砂质黏土10种类型。海区中分布范围最广泛的是粉砂质砂和黏土质粉砂,而砾石和粉砂的分布范围相对较小。海区主要由老铁山水道、冲刷槽砂砾区、渤中砂质浅滩和辽东砂质浅滩、渤中粉砂质平原、渤海湾黏土层粉砂三角洲平原和渤西滨岸倾斜砂质平原五个沉积物粒度分区。主导海区沉积物分布模式的动力机制是进入渤海的黄海暖流余脉形成的渤海环流,另外,渤海海峡强潮流、辽东湾环流和莱州湾环流也是控制区域表层沉积物的重要动力因素。这些动力驱动因素促成了渤海物质与黄海物质之间“北进南出”的交换模式。

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

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.