Chronological implications of changes in the accumulation rate of long marine cores from the continental shelf, southeastern Korea

Three long marine cores collected from the southwestern part of the Ulleung Basin in the East Sea were investigated in terms of chronology, from the middle Pleistocene to Holocene. We propose an age-depth model in cores 19ESDP-101, 19ESDP-103, and 19ESDP-104 obtained through precise age data using a suitable statistical method and classified in chronological units according to their accumulation rates. Changes in accumulation rate in cores 19ESDP-103 and 19ESDP-104, located at the entrance to the contact of the Korean Strait and the Ulleung Basin, showed good agreement with glacial and interglacial cycles. Relatively increased accumulation rates are related to ocean currents flowing through the Korea Strait during interglacial periods of Marine Isotope Stage (MIS) 5 and 7. However, core 19ESDP-101 obtained from the Hupo Basin, located in the northern site, showed a high accumulation rate in the glacial periods of MIS 6 and 8. It is interpreted as an increase in the sediment input from the exposed shallow shelf and inland fluvial, despite the fact that ocean currents from the Korea Strait are blocked by the exposed shelf platform as the sea-level falling down. These results show that the continental shelf on the western East Sea has been deposited from various factors related to several sea-level fluctuations from the glacial-interglacial cycle during the middle to late Quaternary. This study contributes to stratigraphic study in the Korean continental shelf environment of the East Sea from the middle Pleistocene to Holocene.

Automated summary

Three long marine cores from the Ulleung Basin in the East Sea were analyzed to determine their chronology. The accumulation rates in the cores showed good agreement with glacial and interglacial cycles, and the sediment input was influenced by different factors such as ocean currents and sea-level fluctuations. This study provides important information for understanding the stratigraphy of the Korean continental shelf environment from the middle Pleistocene to Holocene.