Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS10] Paleoclimatology and paleoceanography

Wed. May 23, 2018 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Atsuhiko Isobe(Research Institute for Applied Mechanics, Kyushu University), Akihisa Kitamura(静岡大学理学部地球科学教室, 共同), Masaki Sano(Faculty of Human Sciences, Waseda University), Hitoshi Hasegawa(Faculty of Science and Technology, Kochi University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Michinobu Kuwae(Center for Marine Environmental Studies)

[MIS10-P15] Abrupt warming at the onset of last deglaciation inferred from isotopic composition of fluid inclusions from a stalagmite in Okinawa

*Koki Nakamura1, Satoru Mishima1, Kanako Omine1, Ryuji Asami2, Jin-Ping Chen3, Chuan-Chou Shen3, Ryu Uemura1 (1.University of the Ryukyus, 2.Tohoku University, 3.Dept. of Geosci., National Taiwan University)

Keywords:stalagmite, fluid inclusions, stable isotope, last deglaciation

Millennial scale abrupt climate changes have been occurred during the last deglaciation. Stalagmites is one of the most important archive to reconstruct terrestrial climate change in low- and mid-latitudes areas because of their high-accuracy of U-Th dating. However, interpretation of oxygen isotopic ratio (δ18Oca) of calcite is not straightforward because it is controlled by two factors; δ18O of dripwater and temperature at calcite formation.
Oxygen isotope ratio (δ18Ofi) and hydrogen isotopic ratio (δDfi) of fluid-inclusions water preserve past isotopic ratios of drip water. Thus, they are useful to reconstruct not only the isotope composition of past rain water but also changes in temperature. In this study, we analyzed the δ18Ofi and δDfi in the fluid inclusions and the δ18Oca of a stalagmite. A stalagmite, HSN2, was collected in Hoshino cave in Minami Daito Island, Okinawa, Japan. The isotope compositions of fluid inclusion water were measured using a semi–automated version of our fluid inclusion analysis system (Uemura et al., 2016). The δ18Oca of calcite was measured using Gas-bench CF–IRMS (Delta V advantage). U-Th dates was measured at National Taiwan University. The stalagmite HSN 2 has grown continuously from about 21,800 to about 13,400 years before present, and thus covering a important transition period between the Last Glacial Maximum (LGM), Heinrich stadial 1 (H1), and Bølling-Allerød (BA). The temperature variation estimated from δ18Ofi and δ18Oca shows significant increase in temperature from H1 to BA.