The element geochemical behavior and provenance of marine sediments are of significance to understanding the oceanic material cycle. Here, we tested the grain size and major and trace elements of 35 surface sediments in the offshore area of Sierra Leone, analyzed the content characteristics and controlling factors of the elements, discussed the material source of the sediments, and made a comparative study with the sediments in the offshore area of China. The results show that sandy silt is the main sediment type in the research area, and the average sediment mean grain size (Mz) is 4.15Φ. The content of Ca in the samples is the highest among the major elements (except Si), with an average of 5.1%. The content of Sr is the highest among the trace elements (except Ti, P, and Mn), with an average of 378.2 μg/g. The results of correlation analysis and factor analysis show that there are three main sources of sediments in the research area, namely, terrigenous weathering products, ilmenite-dominated ore, and oceanic biochemical substances. Compared with the sediments in China offshore, the sediments in the study area are more affected by marine biochemistry and have special ore input characteristics.

Bays are active land–sea transition zones where the internal hydrodynamic processes control the material exchange between the bay and open sea. Yet, the differences and potential connectivity of those processes between adjacent bays and off-bay areas remains understudied. Using in situ observations during a spring tide in May 2020, complemented with satellite imagery and reanalysis dataset, this study examines sediment dynamics in two neighboring bays of central Fujian—Shenhu Bay (SHB) and Weitou Bay (WTB). Results show that SHB exhibits tidal asymmetry with strong offshore export, while WTB has weaker, vertically divergent residual currents with bottom-layer seaward suspended sediment flux. Outside the bays, residual currents and sediment flux follow a northeastward coastal pathway under late-spring circulation. Sediment transport from bay interiors to mouths and is further transported downstream by regional circulation, potentially entering adjacent bay through exchange between the bay and the open sea. Mechanism analysis indicates that Eulerian residual currents dominate net sediment transport, whereas tidal pumping is minor. These findings reveal sediment export pathways and inter-bay connectivity, advancing understanding of coastal sediment dynamics and material cycling in Fujian waters.