Dome Fuji ice core gas data (112 - 2001m, 15N, O2/N2, Ar/N2)

The variations of O2/N2 and Ar/N2 in the Dome Fuji ice core were measured from 112 m (bubbly ice) to 2001 m (clathrate hydrate ice) at high precision. Our method, combined with low storage temperature (-50 degreeC) successfully remove post-coring gas-loss fractionation signals from our data. From bubbly ice to the middle of bubble-clathrate transition zone (BCTZ) (112 - 800 m) and below the BCTZ (>1200 m), the O2/N2 and Ar/N2 data exhibit orbital-scale variations similar to local summer insolation. The data in the lower BCTZ (800 - 1200 m) have large scatters, which may be caused by mm-scale inhomogeneity of air composition combined with finite sample lengths. In the clathrate hydrate zone, the scatters around the orbital-scale variability decrease with depth, indicating diffusive smoothing of O2/N2 and Ar/N2. A simple gas diffusion model was used to reproduce the smoothing and thus constrain permeation coefficients of the gases. Relationship between Ar/N2 and O2/N2 is markedly different for the datasets representing bubble close-off (slope ~0.5), diffusion within the ice sheet (~1), and post-coring gas-loss (~0.2), suggesting that the dominant fractionation processes are different for those cases. The method and data presented here may be useful for improving the orbital dating of deep ice cores over the multiple glacial cycles and further studying non-insolation-driven signals (e.g., atmospheric composition) of these gases.