Grain size and clay mineral characteristics of surface sediments in the southern North Yellow Sea and their source indications

To identify the sources of sediment materials across different regions and their controlling factors, surface sediments from 138 stations in the southern region of the North Yellow Sea were sampled and the grain size and clay mineral composition and distribution characteristics were analyzed. Results show that the average particle size (Mz) of the surface sediments in the study area ranges from 1.47Φ-6.56Φ, of which sandy silt, silt-like sand, and silt were the predominant types. The Pejrup triangular diagram shows that the overall sedimentary dynamics in the area were strong, particularly in the deepwater areas off Chengshantou. The clay minerals were primarily composed of illite (61.08%) and smectite (19.78%), followed by chlorite (10.92%) and kaolinite (8.22%). The primary source of surface sediment material in the southern part of the North Yellow Sea is continental detritus carried by the Huanghe (Yellow) River, with a potential presence of Yalu River material on the northeast edge of the area. The coastal current of Shandong Peninsula and the northward-moving warm current of Yellow Sea in winter were the main sources of hydrodynamics in the area, and they determined the trend of sediment transport and dominated the spatial distribution of sediments in the study area.