[U-03] 人新世・第四紀の気候および水循環

[U03-P08] Reconstructing Sea Level Dynamics During Marine Isotope Stage 3 Using Fossil Corals From Kikai-jima, Japan.

*Catherine Melissa Smith^1,2、Yusuke Yokoyama¹、Yosuke Miyairi¹、Yuning Zeng¹、David Heslop² (1.Atmosphere and Ocean Research Institute, University of Tokyo、2.The Australian National Univerisity)

キーワード：Coral, Marine Isotope Stage 3, Sea Level, Climate Change, U-Series Dating, Radiocarbon Dating

Despite the urgency of quantifying how sea-level (ie. ice sheets) will respond to ongoing and future climate change, there is still limited knowledge of spatial and temporal distribution of ice sheets and global sea-level throughout most of the last glacial period (120 – 11 thousand years ago, ka), which is a key information to model surface deformation due to GIA (Glacio-isostatic adjustment: Yokoyama and Purcell, 2021). Marine Isotope Stage 3 (MIS3; 57 – 30 ka) is a period in geological time characterised by unusual and rapid fluctuations in climate due to a series of events. That is, more than fourteen abrupt warming periods known as Dansgaard-Oeschger events (D-O), and at least six intense intervals of ice discharge episodes known as Heinrich events (H) (Yokoyama and Esat, 2011). However, there is still debate regarding sea level magnitude during the MIS3 (eg., Yokoyama et al., 2022; Gowan et al., 2022), hence further constraints from the field far-away from former ice sheets are needed. In this study, we sampled uplifted fossil corals and marine material from three drill cores located in Araki, Kikai-jima, Japan. We screened the corals for diagenesis using X-ray diffraction analysis and dated them using mass spectrometric U-series and radiocarbon dating methods. The aim of this study was to quantify how relative sea-level changed during MIS3 and elucidate how sea-level responded to rapid shifts in climate during the last ice glacial period prior to the last glacial maximum.