渤海海峡限制性地形对现代沉积体系分布的控制OA

[Objective]The formation of sedimentary systems within straits is intricately linked to the unique topo-graphical constraints that influence both facies characteristics and sediment distribution patterns.Although current re-search mainly focuses on narrow straits(less than 50 km wide),where sedimentation is dominated by tidal process-es,wider straits introduce more complex hydrodynamic dynamics,leaving many aspects of the sedimentation process-es yet to be fully understood.[Methods]This study focuses on the Bohai Strait(a shallow strait with a width of 106 km)and is based on an extensive dataset of surface sediment grain sizes,combined with four shallow seismic pro-files,to characterize the sedimentary environment within the Bohai Strait.Additionally,a regional ocean modeling system(ROMS)simulation was employed for winter(December 2020-February 2021)to better understand the hydro-dynamic processes influencing sediment dynamics and control over sediment distribution within and surrounding the Bohai Strait.[Results]Our results reveal significant differences in sediment dynamics between the northern and southern parts of the strait.The northern region exhibits a high-energy environment dominated by erosion,whereas the southern region displays a lower-energy environment conducive to deposition.Surface sediment types vary spatial-ly,with coarser grains predominating in the north and narrow regions,with finer grains observed on both sides(east-west)and in the south.A large-scale,sandy flood-tidal delta appears around the Laotieshan Channel in the north.The asymmetric tidal currents flowing in and out of the channel are likely responsible for this feature,and ebb-tidal delta is not prominent.In contrast,the southern part of the strait exhibits two distinct sedimentary systems:(1)Shan-dong mud wedge:This system lies along the coast of the Shandong Peninsula,shaped by the substantial sediment supply from the Yellow River and the influence of coastal currents.(2)Scour troughs and sandy tidal deltas:These smaller features are attributed to the protective effect of islands present in the southern strait,combined with the abundant supply of fine-grained sediments.[Conclusions]This study highlights the critical role of the complex topog-raphy of the strait in the confinement in shaping regional sediment transport dynamics and the resulting distribution of sedimentary systems.