[M-IS15] 南大洋・南極氷床が駆動する全球気候変動

[MIS15-P11] Revising the Dome Fuji ice core chronology

*大藪 幾美¹、川村 賢二^1,2,3、北村 享太郎¹、Parrenin Frédéric ⁴、Orsi Anais⁵、Buizert Christo⁶ (1.情報・システム研究機構　国立極地研究所、2.総合研究大学院大学、3.海洋研究開発機構、4.フランス地球環境研究所、5.フランス気候環境科学研究所、6.オレゴン州立大学)

キーワード：年代スケール、氷床コア、ドームふじ

Precise chronology is essential for paleoclimate proxies to examine the sequences, durations and phasing of the climate records, as well as for numerical simulations, both for their input and validation data to better understand the transient behaviors of climate and ice sheet. The chronology of the Dome Fuji ice core over the last 340 kyr was constructed by synchronizing variations in the O₂/N₂ ratio of occluded air with local summer insolation (Kawamura et al., 2007) with stated uncertainty of less than ~2.5 kyr in general. The accuracy of the chronology is generally supported by the comparison with a radiometric (U-Th) dating of Chinese speleothem records (Cheng et al., 2009), but relatively large errors were recently found around the last interglacial period (Fujita et al., 2015). Here, we revise the Dome Fuji chronology using newly acquired O₂/N₂ ratio (summer insolation proxies), new densification models and 1-D ice flow model (PaleoChrono), and discuss the timing of penultimate deglaciation from atmospheric records of CH₄ concentrations and δ¹⁸O of O₂ in the Dome Fuji ice core.

References
Fujita, S. et al. (2015), Clim. Past., 11, 1395-1416 .
Kawamura, K., et al. (2007), Nature, 448, 912-916.
Cheng, H. et al. (2009), Science, 326, 248-252.