HR: 0800h
AN: PP41B-0547    [Abstracts]
TI: A switch from carbonate ocean to silica ocean in the East Sea (Sea of Japan) during the mid- Pleistocene
AU: * Khim, B
EM: bkkhim@pusan.ac.kr
AF: Division of Earth Environmental System, Pusan National University, Jangjeon-dong Geumjeong-gu, Busan, 609-735, Korea, Republic of
AU: Kido, Y
EM: kido@eps.s.u-tokyo.ac.jp
AF: Department of Earth Planetary Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
AU: Jordan, R W
EM: sh081@kdw.kj.yamagata-u.ac.jp
AF: Department of Earth and Environmental Sciences, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-8560, Japan
AU: Bahk, J
EM: jjbahk@kigam.re.kr
AF: Petroleum and Marine Resources Division, KIGAM, Gajeong-dong, Yuseong-gu, Daejeon, 305-350, Korea, Republic of
AU: Itaki, T
EM: t-itaki@pusan.ac.kr
AF: Division of Earth Environmental System, Pusan National University, Jangjeon-dong Geumjeong-gu, Busan, 609-735, Korea, Republic of
AU: Tada, R
EM: ryuji@eps.s.u-tokyo.ac.jp
AF: Department of Earth Planetary Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
AB: In this study, we report on the extraordinary CaCO₃ preservation in the East Sea (Sea of Japan) during the mid-Pleistocene, which provides a new perspective of carbon cycling as a carbonate ocean. Core 96EBP3 collected from the South Korea Plateau and core MD01-2407 collected from the Oki Ridge show extraordinary downcore variation of CaCO₃ contents. CaCO₃ contents of core 96EBP3 were measured using UIC coulometer (Model CM5014) and those of core MD01-2407 were converted from CaO measurement using high- resolution major element analysis data determined by an XRF microscanneran (Horiba XGT-2700). The correlation between these two cores was conducted with diverse approaches; radiolarian extinction, warm-water species of radiolaria, and CaCO₃ variation. These two cores are in accordance with various features, although core 96EBP3 records some missing ages of MIS 9 and 10. The lower parts of both cores are characterized by extraordinarily high CaCO₃ contents up to 50%. The high CaCO₃ contents occurred before MIS 11 in both cores. The major constituents of these CaCO₃ are coccoliths derived from calcareous nannoplankton. Therefore, these durations of high coccolith dump are quite unique in the East Sea, suggesting that the present-day silica ocean has, periodically in the past, been a carbonate ocean too.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3030 Micropaleontology (0459, 4944)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4912 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4805)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting