Buried ice deposits represent a new and potentially far-reaching archive of atmosphere and climate on Earth extending back for many millions of years. These deposits potentially are terrestrial analogs to widespread and young buried ice on the Martian surface.
Just as earlier researchers asked whether a climate record was stored in modern ice sheets of Antarctica and Greenland, we now ask whether ancient, debris-covered glaciers in the Dry Valleys hold similar records of temperature and atmospheric change, but on timescales that are perhaps an order of magnitude greater than that for the deepest existing ice core.
We are currently evaluating the age, origin, and climatic significance of buried ice in the western Dry Valleys region. Our group and others have published evidence that the ice is over a million years in age, making it by far the oldest ice yet known on this planet. An alternative view is that the buried ice is more recent segregation ice from the in-situ freezing of groundwater. Distinguishing between these hypotheses is key to understanding Neogene climate change of Antarctica.
We have assembled a diverse research team with expertise in Antarctic geomorphology, numerical modeling, cosmogenic dating, 40Ar/39Ar analyses, ice-core analyses, and ice-core drilling technology. Recent goals have been to: 1) understand better the surface processes that permit ice preservation, 2) test the efficacy of cosmogenic and 40Ar/39Ar analyses in dating tills above buried ice, 3) further assess the use of cosmogenic-nuclide analyses and 40Ar/39Ar analyses of ashfall deposits to date buried ice, and 4) use these data to help resolve the debate between "young" and "old" ice scenarios.
Much of our recent work has focused on numerical modeling of vapor diffusion through porous media. From these quantitative models, we have shown that buried-ice deposits in the far-western Dry Valleys sublimate at an average rate of 0.1 mm a-1, with rates reduced to < 0.001 mm a -1 if summertime temperatures drop by ~ 3°.
With our collaborator, Michael Bender of Princeton University, we are just beginning to analyze gasses trapped within multi-million year old ice deposits in Mullins and Beacon valleys.
To learn more about our research on buried ice deposits, visit the PolarTREC website here. Jackie Hams is a PolarTREC teacher who visited with the research team during multiple seasons.
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