Evolution of late Quaternary deposits in the southern Yellow Sea

In the southern Yellow Sea, we collected high-resolution seismic profiles to investigate the evolution of late Quaternary deposits. Approximately 1,500 line-km data of chirp and sparker profiles were acquired. We also used a deep drill core to interpret the sedimentary sequence. High-resolution seismic profiles show the Holocene mud deposits dominated in the study area, ranging from 10 to 40 m in thickness, and the complex sedimentary structure. The late Quaternary deposits in the study area can be divided into four sedimentary units (units A, B, C, and D from the oldest to youngest) bounded by an erosional surface and internal seismic reflector: (1) incised channel fill/lowstand deltaic wedge (unit A), (2) transgressive sand ridges and sand sheets (unit B), (3) estuarine/deltaic or shallow-water mud (unit C), (4) distal mud patch (unit D). Unit C is divided into two sedimentary sub-units by high amplitude and unconformity: (a) estuarine/deltaic mud (unit C-a), (b) redeposited mud by a sea-level rise and strong tidal current (unit C-b). The evolution of units C-a and C-b is closely related to the post glacial sea-level changes, sediment erosion, and reworking. Based on the interpretation of high-resolution seismic records and correlation with the YSDP-102, upper section of YSDP-102 core corresponds to the late transgressive systems tract regarded as redeposited mud (unit C-b), whereas lower section of YSDP-102 core correspond to unit B. These late Quaternary deposits controlled by sea level change, tidal currents, and sediment erosion.