The high elevation Dry Valleys in Antarctica as analog sites for subsurface ice on Mars

The high elevation valleys of the McMurdo Dry Valleys of Antarctica are the only locations on Earth known to contain dry permafrost. The Dry Valleys are a hyper-arid polar desert environment and above 1500 m elevation, air temperatures do not exceed 0 °C and thus, similarly to Mars, liquid water is largely absent and instead the hydrologic cycle is dominated by frozen ice and vapor phase processes such as sublimation. These conditions make the high elevation Dry Valleys a key Mars analog location where periglacial processes and geomorphic features, and their use as a diagnostic for subsurface ice, can be studied in situ. Two valleys in the upper Dry Valleys show a diversity of subsurface ice; University Valley is dominated by dry permafrost overlying ice-cemented to ice-bonded ground and nearby middle Beacon Valley is dominated by massive ground ice. In both cases the ice is 10–60 cm below the surface. Here we compare the surface features in these two valleys to assess any correlation with the nature of the subsurface ice and compare these features to similar features seen at the Phoenix landing site on Mars. We conclude that while surface features may be indicative of ground ice, no specific correlations are possible and more direct methods are required to determine the nature of subsurface ice on Mars.