Grain size characteristics and dynamic environment of surface sediments on the near shore seabed of Dingzi Bay

126 surface sediment samples were collected from the near shore seabed of Dingzi Bay in Shandong province for grain size analysis. Grain size parameters of the samples are calculated and sediment types determined. Upon the basis, sediment transport trends were studied using the Gao-Collins Grain Size Trend Analysis (GSTA model). Sedimentary hydrodynamics was defined using Pejrup triangular diagram. Results indicate that there are eight types of sediments in the bay, dominated by sand, sandy silt and silt. The sediments, in general, are getting finer from the shore to the ocean. They are poorly and very poorly sorted, positively and very positively skewed, and moderate in kurtosis. There are two kinds of sediment transport patterns. In the area near the shoreline, the sediment is transported from the coast to the center of the bay, while in the offshore area, sediment moves from the northwest to southeast. Relatively strong sedimentary hydrodynamics occur in the coastal area. It becomes weaker when water gets deeper.