Thursday, 30 August 2007 - 11:10 AM
4.A.C-4
Quantifying sublimation of buried glacier ice in Beacon Valley
Douglas E. Kowalewski and David R. Marchant. Department of Earth Sciences, Boston University, 675 Commonwealth Ave, Boston, MA 02215
A remnant of Taylor Glacier ice rests beneath a 40-to-80-cm-thick layer of sublimation till in central Beacon Valley, Antarctica. Our 1-D vapor diffusion model, with input from micrometeorological data collected during the 2004 austral summer, shows that vapor flows into and out of sublimation till at rates dependent on the non-linear variation of vapor concentration with depth. Although measured meteorological conditions during the study interval favored a net loss of buried glacier ice (~0.017 mm over 42 days), an average rate of ice sublimation that is consistent with a loss of 400 m of ice over 8.1 Ma (an amount suggested by Potter et al., 2003) is permissible if local temperatures decrease by ~3ºC; relative humidity increases by 15%; or snowmelt infiltration equals ~0.001 mm/day. Our model results are consistent with the potential for long-term survival of buried glacier ice in the hyper-arid upland zone of the Dry Valleys.