[M-IS15] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

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

*Ikumi Oyabu¹, Kenji Kawamura^1,2,3, Kyotaro Kitamura¹, Frédéric Parrenin⁴, Anais Orsi⁵, Christo Buizert⁶ (1.National Institute of Polar Research, Research Organization of Information and Systems, 2.The Graduate University of Advanced Studies (SOKENDAI), 3.Japan Agency for Marine Science and Technology (JAMSTEC), 4.Institut des Géosciences de l'Environnement, 5.Laboratoire des sciences du climat et de l'environnement, 6.Oregon State University)

Keywords:chronology, ice core, Dome Fuji

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.