Abstract:
The geophysical metronome (Milankovitch components of the past surface temperature variations) and the isotope-temperature transfer function deduced from the borehole temperature profile at Vostok station, Antarctica, are applied to date the 2500 m deep ice core from Dome Fuji station, Antarctica, and to reconstruct paleoclimatic conditions at the drilling site on the basis of the local δ18O isotope record. Special attention is paid to consistency of this depth-age relation with the mass-balance reconstruction and predictions of ice-flow modeling. The present-day ice mass-balance rate at Dome Fuji is estimated as 3.2 cm a-1. The ice age at the borehole bottom (590 m above the bedrock) is around 335 ± 4.5 kyr and may reach 2000 kyr at about 3000 m depth. The difference in the ice-sheet surface temperatures between Holocene optimum and Last Glacial Maximum is found to be 17.8°C at the temporal isotope/temperature slope, about 30% lower than the modern geographical estimates. A good agreement between modeled and measured (preliminary data) borehole temperatures is obtained at the geothermal flux 0.059 W m-2 and ice-fusion temperature (-2°C) at the ice-rock interface with minimum (zero) melt rates.
