[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

*Takuya Sagawa¹, Yusuke Narita², Masahiro Yokoyama³, Takashi Hasegawa¹, Yoshimi Kubota⁴, Yusuke Okazaki⁵ (1.Institute of Science and Engineering, Kanazawa University, 2.Graduate School of Natural Science & Technology, Kanazawa University, 3.Collage of Science and Engineering, Kanazawa University, 4.National Museum of Nature and Science, 5.Kyushu University)

Keywords:Japan Sea, paleotemperature reconstruction, Dansgaard-Oeschger Event

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.