[MIS23-P05] Paleoclimate records in stalagmites from Okinoerabu-jima, Ryukyu Islands, Japan
Keywords:stalagmite, paleoclimate, oxygen isotope composition, carbon isotope composition, Holocene, Ryukyu Islands
Here, we present oxygen and carbon isotope time series of 17 stalagmites collected at 4 caves in Okinoerabu-jima, the Ryukyu Islands, Japan. The Hendy Test performed in this study suggests that the isotope profiles along the center of stalagmite growth appear to be primarily of environmental origin with little effects of kinetic fractionation. Since 2014, we have observed cave environments using loggers and collected water samples to establish relationship between oxygen isotope composition of drip waters and stalagmites. We generate a well-dated time series of the oxygen and carbon isotope ratios in stalagmites using a high-precision U-Th dating method to reconstruct hydroclimate changes around the Ryukyus during the Quaternary, especially Holocene. Coupled with previously published stalagmite records from China (e.g., Wang et al., 2001) and Japan (Shen et al., 2010; Sone et al., 2013; Uemura et al., 2016), our study can allow a better understanding of past spatial climate changes associated with the East Asian Monsoon.
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