[M-IS12] Paleoclimatology and paleoceanography

[MIS12-P17] Millennial-scale oscillations in the southern Bering Sea during the last 50 kyrs

*Yusuke Okazaki¹, Hirofumi Asahi², Shinya Iwasaki³, Ruka Kubota¹, Kozo Takahashi¹ (1.Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University, 2.Fukui Prefectural Satoyama-Satoumi Research Institute, 3.Graduate School of Environmental Science, Hokkaido University)

Keywords:Bering Sea, Last glaciation, Millennial scale oscillations

We present downcore profiles of the multi-proxy records in a piston core BOW-9A from the Bowers Ridge at 2400 m water depth in the southern Bering Sea obtained during KH99-3 cruise by R/V Hakuho-maru in the summer of 1999. The age model of BOW-9A was established by radiocarbon dates of planktic foraminifera, benthic foraminiferal oxygen isotope stratigraphy, and paleointensity. Millennial-scale oscillations were found in the CaCO3 contents and planktic foraminiferal isotope records during the marine isotope stage (MIS) 3. The number of the CaCO3 peaks was much smaller than the Dansgaard-Oeschger events (D-O events), perhaps corresponding to the long interstadials such as D-O events 8, 12, and 14. Similar patterns in CaCO3 contents were also reported in the northern Bering Sea. Biogenic opal contents during MIS 3 ranged from 20 to 50 wt%, comparable to those during MIS 1.