Palynological implications for paleoenvironmental changes over the past 81,000 years on the Jeju Strait shelf, off southwestern Korea

Age-controlled palynostratigraphy has revealed changes in the depositional environment, vegetation, and climate of the southwestern Korean Peninsula since marine isotope stage (MIS) 5a. During MIS 5a (ca. 74–81 ka), the Jeju Strait shelf was an inner shelf with deposition influenced by the Jeju Warm Current (JWC), surrounded by land covered by mixed conifer and deciduous broadleaf forests under warm temperate conditions. The paleoenvironment during MIS 4 (57–71 ka) remains unknown due to a lack of palynomorphs from this stage. During mid–late MIS 3 (ca. 29–50 ka), the Jeju Strait shelf was an inner shelf influenced by cold-water masses from the Korean Coastal Current combined with weaker influences by the JWC, and the surrounding land was covered by mixed conifer and deciduous broadleaf forests that were less dense than in MIS 5a under warm and relatively dry conditions. A cold, slightly wet climate during MIS 2 (ca. 12–29 ka) led to the extension of predominantly cold-tolerant conifer forests due to lowstand sea levels, although inland East Asia remained cold and dry. During MIS 1 (ca. 0–12 ka), cold-tolerant conifer forests persisted into the early Holocene, and were subsequently replaced by mixed conifer and deciduous broadleaf forests as a warm climate was restored in the mid–late Holocene, when the depositional environment became an outer shelf due to highstand sea levels, as it remains today. •We reconstructed Jeju Strait shelf depositional environments since marine isotope stage 5a.•Sea surface temperature-dependent dinoflagellate cysts reflect the relative influences of two currents in the Jeju Strait.•Changes in bisaccate/deciduous broadleaf pollen ratios correspond to sea-level changes.