Seismic Stratigraphy and Depositional History of Late Pleistocene-Holocene Deposits in the Jeju Strait, Korea

Lee, B.-R.; Yoo D.-G., and Lee, G.-S., 2020. Seismic stratigraphy and depositional history of late Pleistocene-Holocene deposits in the Jeju Strait, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 548–552. Coconut Creek (Florida), ISSN 0749-0208. In this study, high-resolution seismic reflection profiles and core samples from the Jeju Strait shelf were analyzed to determine depositional and erosional processes that occurred during the late Quaternary. The results show that late Quaternary deposits in the Jeju Strait comprise six seismic units, consisting of a set of lowstand, transgressive, and highstand systems tracts formed since the last glacial maximum (LGM). The study area was mostly exposed during the LGM (>19 ka BP). An incised channel, such as paleo-Yellow and Yangtze Rivers of China and Korean Rivers, was cut across the continental shelf. Unit 1, the lowermost unit, is regarded as channel-fill deposits formed since the LGM. As the shelf was flooded, the depocenter migrated to the inner-shelf and four units (unit 2-5), regarded as transgressive deposits, developed on the shelf. The uppermost unit 6 consists of Seomjin prodelta developed after the recent highstand of sea level about 6 ka BP. The stratigraphic architecture including the six units is controlled by sea-level change, hydraulic conditions, and sediment supply.