[M-IS12] Paleoclimatology and paleoceanography

[MIS12-P24] A 90,000-year isotope record of stalagmite core samples from Minami-Daito Island, Okinawa, Japan

*Yuta Arimura¹, Ryu Uemura¹, Syed Azharuddin¹, Osamu Abe¹, Ryuji Asami², Yuan Shufeng³, Chin Hahjung³, Wang Xianfeng³ (1.Nagoya University, 2.Tohoku University, 3.Nanyang University)

Keywords:paleoclimate, isotope, speleothem, stalagmite

The Asian monsoon is a climate system that affects the lives of billions of people, and various proxies have been proposed to interpret patterns of variability. Among these, the stable isotope of oxygen (δ¹⁸O) in stalagmite carbonate in caves is an excellent proxy to reconstruct precipitation and temperature in the Asian monsoon region. Stalagmites δ¹⁸O from in China preserve continuous data over long periods of time, with variations corresponding to Dansgaard-Oeschger events (D-O events) on millennial scales (Cheng et al., 2016). However, stalagmites δ¹⁸O such as Kiriana Cave and Ohtaki Cave in Japan lack clear signals corresponding to D-O stalagmites (Mori et al., 2018). To interpret these regional differences climatologically, it is important to obtain long-term data in new regions. Therefore, we collected long stalagmite cores by boring through the center of large stalagmites at Yamashita Cave on Minami-daito Island, Okinawa Prefecture. U-Th dating of two of the stalagmite cores revealed a growth period of 12.5 to 91.1 kyr BP. Since Minami-daito Island is in the subtropical northwest Pacific Ocean, we will discuss the sea-land difference by comparing with monsoon records from China.