[M-IS02] Evolution and variability of the Asian Monsoon and Indo-Pacific climate during the Cenozoic Era

[MIS02-P04] Millennial-scale displacement of the subpolar front during the Marine Isotope Stage 3 in the Japan Sea

*佐川 拓也¹、成田 祐亮²、横山 真大³、長谷川 卓¹、久保田 好美⁴、岡崎 裕典⁵ (1.金沢大学理工研究域、2.金沢大学大学院自然科学研究科、3.金沢大学理工学域、4.国立科学博物館、5.九州大学)

キーワード：日本海、古海水温復元、ダンスガードオシュガーイベント

Millennial-scale variability of the East Asian monsoon during the last glacial period suggests a tight coupling of climate between East Asia and the high-latitude North Atlantic. Environmental change in the Japan Sea is also the case as evidenced by the sedimentary color variations, a proxy for productivity/oxygenation of bottom water, that show oscillations similar to the Dansgaard-Oeschger Event. However, the relationship between these environmental change and sea surface temperature (SST) is not yet investigated. This study provides high-resolution Mg/Ca-based winter SST records from two sediment cores of the southern Japan Sea during Marine Isotope Stage 3 (MIS3). The SST differences between sites fluctuated on the millennial timescale and were concordant with the dark-light sediment color oscillations with larger (smaller) ΔSST in dark (light) layers. As the SST amplitude is significantly larger in the southern site, we interpret ΔSST oscillations as a migration of the subpolar front, which only crossed the southern site in response to the millennial-scale change of the East Asian winter monsoon and/or the Tsushima Warm Current inflow from the East China Sea.