[M-IS14] Paleoclimatology and paleoceanography

[MIS14-04] High-resolution reconstruction of “Stormy two centuries” at the onset of Bølling-Allerød warming period using stalagmite from Shiga, Japan

*Nodoka Kuramoto¹, Masayuki Ikeda¹, Chuan-Chou Shen^2,3, Akihiro Kano¹, Chun-Yuan Huang², Yuji Abe⁴ (1.Department of Earth and Planetary Science, The University of Tokyo, 2.Department of Geosciences, National Taiwan University, 3.Atmosphere and Ocean Research Institute, University of Tokyo, 4.Taga Town Museum)

Keywords:Global warming, Holocene, late glacial, stalagmite, δ18O, δ13C

It has been proposed that about 15,000 years ago, the Late glacial interstadial (equivalent to GI-1/Bølling-Allerød) started ca. two centuries earlier in East Asia than in the North Atlantic based on the pollen data from the annually-laminated Lake Suigetsu sediment with ¹⁴C dataset (e.g., Nakagawa et al., 2021). However, comparisons of timings of past climatic events among regions often remain hypothetical due to chronological limitations. Here we present the result of high-resolution δ¹⁸O and δ¹³C records that covers the onset of Bølling-Allerød warming period from U-Th dated stalagmite, KK-2, from Shiga Prefecture, 50 km southeast of Lake Suigetsu. Precise U-Th dating with a 2-sigma uncertainty of less than ±1% was obtained at the High-precision mass spectrometry and environment change laboratory (HISPEC), National Taiwan University. Brownish layers were observed from 21 to 22 cm from the top of stalagmite. This age is consistent with the onset ages of the late glacial subinterglacial (GI-1: Bering-Adelaide stage) in Greenland ice core (NGRIP) at 14743 ± 104 U-Th yr BP (±2σ, hereafter; relative to 1950 CE) and in Lake Suigetsu sediment at 14970 ± 82 IntCal20 yr BP (Nakagawa et al., 2021) coincides within the error with the end of the ‘stormy two centuries’ (14760 ± 110 IntCal20 yr BP). The change of δ¹⁸O and δ¹³C from brown layers, likely formed by flooding events, are synchronous with those of Maboroshi cave in Japan, and Chinese caves (Shen et al., 2010 and reference therein). This brown-layer alternation corresponds to the ‘stormy two centuries’, which can provide high-precision chronology across the Bølling-Allerød warming period.