DISTRIBUTION PATTERN OF THE SURFACE SEDIMENTS IN SOUTHERN BOHAI STRAIT AND CONTROLLING FACTORS

Based on the grain size data of 208 surface sediment samples in the southern Bohai Strait, combining the mineralogy of sediments with the water dynamic conditions, this paper discussed the distribution pattern of the surface sediments and its controlling factors. The results show that:1) Surface sediments vary in grain size, but are dominated by coarse-grained sediments. Pebbles are widely distributed in the waterways between the islands and land, the rocky coasts and the subtidal area near the Dengzhou Shoal. 2) The sorting of coarse sediments is generally poor or very poor, instead, the fine-grained sediments are well sorted. And the skewness is generally positive which is higher in the east region compared to the west. 3) Terrestrial residual sediments occur in the east of the study area, while the west of the study area is a transitional zone of the fluvial deposits of the Yellow River and other rivers to the southwestern Laizhou Bay and the eroded debris from the islands along the Shandong Peninsula; 4) The grain size distribution in the southern beach of the study area is controlled by waves, in contrast grain size distribution in offshore areas, waterways between islands and the land and the areas near the rocky headland is mainly controlled by tidal currents.