[A-CG36_30PO1] 北極域の科学

[ACG36-P21] 北極海チャクチボーダーランドにおける過去１５.５万年にわたる古環境変動

内田 昌男¹、熊田 英峰²、*近藤 美由紀¹、レラ シュテファン¹、芝原 暁彦³、天野 千恵⁴、内海 真生⁵ (1.国立環境研究所、2.東京薬科大学、3.産業総合技術研究所、4.東洋大学、5.筑波大学)

Knowledge on past variability of sedimentary organic carbon in the Arctic Ocean is important to assess natural carbon cycling and transport processes related to global climate changes. However, the late Pleistocene oceanographic history of the Arctic is still poorly understood. In the present study we show sedimentary records of organic carbon(TOC, δ13C), CaCO3, benthic and planktonic foraminiferal δ18O, BIT index for terrestrial organic carbon input, IP25 for sea ice condition, and the coarse grain size fraction. The 8m length sediment core was retrieved in the northern Northwind Ridge in the far western Arctic Ocean, during the MR08-05 cruise by R/V Mirai. An age model based on oxygen isotope stratigraphy, radiocarbon dating and lithological constraints suggests that the core records paleoenvironmental changes of the last 155 kyr. In this conference, we discuss presented millennial scales records of glacial erosion, intermediate water and/or surface water and sea ice variabilities during cold/warm episodes of the last two glacial interglacial cycles in the light of ice sheet and ocean-atmosphere dynamics.