Sequence stratigraphy of the late Quaternary deposits in the southern Jeju Island

Distribution pattern of the Holocene mud deposits and the sequence stratigraphy of late Quaternary in the southern Jeju Island of Korea were interpreted using the high-resolution seismic profiles (Chirp and Sparker system). Approximately 700 line-km data of chirp and sparker profiles were acquired in the study area. We also used a deep drill core to interpret the sedimentary sequences, and 11,000 line-km data of Chirp profiles provided by the National Oceanographic Research Institute of Korea. The late Quaternary deposits in the study area can be classified into three sedimentary units (Units I, II and III from bottom to top). The sedimentary sequences are bounded by an erosional surfaces and internal seismic reflectors: (1) regressive deltaic deposits (Unit I), (2) transgressive estuarine/deltaic complex and sand ridges/sheet (Unit II), and (3) recent mud (Unit III). Based on high-resolution seismic profiles and correlation with the ECSDP-102 core, the Unit I is interpreted as falling stage systems tract, whereas Unit II and Unit III are correspond to transgressive systems tract and highstand systems tract, respectively. The mud deposit showing a circle shape locates about 140 km off the southern Jeju Island and generally occurs at the depth between 60 and 90 m below sea level in this area. It is commonly 1~6 m thick. The circular distribution pattern of the mud deposits appears to be largely controlled by the presence of cyclonic eddy in the southern Jeju Island.