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The effects of snow and salt on ice table stability in University Valley, Antarctica

October 16, 2017

The Antarctic Dry Valleys represent a unique environment where it is possible to study dry permafrost overlaying an ice-rich permafrost. In this paper, two opposing mechanisms for ice table stability in University Valley are addressed: i) diffusive recharge via thin seasonal snow deposits and ii) desiccation via salt deposits in the upper soil column. A high-resolution time-marching soil and snow model was constructed and applied to University Valley, driven by meteorological station atmospheric measurements. It was found that periodic thin surficial snow deposits (observed in University Valley) are capable of drastically slowing (if not completely eliminating) the underlying ice table ablation. The effects of NaCl, CaCl2 and perchlorate deposits were then modelled. Unlike the snow cover, however, the presence of salt in the soil surface (but no periodic snow) results in a slight increase in the ice table recession rate, due to the hygroscopic effects of salt sequestering vapour from the ice table below. Near-surface pore ice frequently forms when large amounts of salt are present in the soil due to the suppression of the saturation vapour pressure. Implications for Mars high latitudes are discussed.

Publication Year 2018
Title The effects of snow and salt on ice table stability in University Valley, Antarctica
DOI 10.1017/S0954102017000402
Authors Kaj E. Williams, Jennifer L. Heldmann, Christopher P. McKay, Michael T. Mellon
Publication Type Article
Publication Subtype Journal Article
Series Title Antarctic Science
Index ID 70191516
Record Source USGS Publications Warehouse
USGS Organization Astrogeology Science Center