[A-CC27] 雪氷学

[ACC27-P04] Meltwater discharge from Wilkes Basin, East Antarctica at around 4.2 ka revealed from Beryllium-10 analysis of marine sediments

*Bethany Behrens^1,2、Yosuke Miyairi¹、Adam Sproson¹、Masako Yamane³、Yusuke Yokoyama^1,2,4,5 (1.Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan、2.Graduate Program on Environmental Science, University of Tokyo, Komaba, Meguro, Tokyo 153-0041, Japan、3.Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Chikusa, Nagoya, Aichi, 464-8601, Japan、4.Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushimacho, Yokosuka, Kanagawa Prefecture 237-0061, Japan、5.Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Hongo, Bunkyō, Tokyo 113-8654, Japan)

キーワード：Holocene, East Antarctica, Adelie Basin, 4.2 ka event, Beryllium-10

Understanding Antarctic ice sheet dynamics related to global climate change is of scientific and societal interest as the future behavior of the ice sheets under currently changing climate is unknown. We present beryllium-10 analysis of a high-resolution marine sediment core from Adélie Basin near the Wilkes Land ice sheet, which is susceptible to retreat due to the low-lying nature and down-sloping trough of the Wilkes Basin. Combined with a newly constructed age model using compound specific radiocarbon dates, the data reveal three ice sheet meltwater discharge events at ca. ~10 ka, ca. ~6.5 ka and ca. ~4 ka. The earlier events correspond to the disappearance of Northern Hemisphere ice sheets and interglacial level atmospheric CO₂. The timing of the latest meltwater influx complements the 4.2 ka event, a period of abrupt global climatic change and the beginning of the Meghalayan Age.