[A-CG36_30PO1] Science in the Arctic Region

[ACG36-P21] Reconstruction of paleoenvironmental changes in the Chukchi Borderland over the last 15.5kyr

Masao UCHIDA¹, Hidetoshi KUMATA², *Miyuki KONDO¹, Stephan RELLA¹, Akihiko SHIBAHARA³, Chie AMANO⁴, Motoo UTSUMI⁵ (1.National Institute for Environmental Studies, 2.Tokyo University of Pharmacy and Life Sciences, 3.National Institute of Advanced Industrial Science and Technology, 4.Toyo University, 5.University of Tsukuba)

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.