Formation and evolution of buried snowpack deposits in Pearse Valley, Antarctica, and implications for Mars

Abstract

Buried snowpack deposits are found within the McMurdo Dry Valleys of Antarctica, which offers the opportunity to study these layered structures of sand and ice within a polar desert environment. Four discrete buried snowpacks are studied within Pearse Valley, Antarctica, through in situ observations, sample analyses, O-H isotope measurements and numerical modelling of snowpack stability and evolution. The buried snowpack deposits evolve throughout the year and undergo deposition, melt, refreeze, and sublimation. We demonstrate how the deposition and subsequent burial of snow can preserve the snowpacks in the Dry Valleys. The modelled lifetimes of the buried snowpacks are dependent upon subsurface stratigraphy but are typically less than one year if the lag thickness is less than c. 7 cm and snow thickness is less than c. 10 cm, indicating that some of the Antarctic buried snowpacks form annually. Buried snowpacks in the Antarctic polar desert may serve as analogues for similar deposits on Mars and may be applicable to observations of the north polar erg, buried ice at the Mars Phoenix landing site, and observations of buried ice throughout the martian Arctic. Numerical modelling suggests that seasonal snows and subsequent burial are not required to preserve the snow and ice on Mars.

Climate and energy balance of the ground in University Valley, Antarctica

“…The maximum depth at which melting occurs is ~5 cm, although this depth is affected by at least a few centimetres based on surface humidity and soil thermal diffusivity, as well as the other surface properties, which may be different from those in University Valley. These results are consistent with observations at Pearse Valley, which show yearly melting of near-surface ice (Heldmann et al 2012).…”

Distribution and origin of ground ice in University Valley, McMurdo Dry Valleys, Antarctica

“…2011, Heldmann et al . 2012). The residual frost is then transported downwards into the soil along the negative soil temperature gradient to form ground ice.…”

Global documentation of gullies with the Mars Reconnaissance Orbiter Context Camera and implications for their formation

“…A top-down snowmelt model has been suggested by previous authors (e.g., (Christensen, 2003;Bridges and Lackner, 2006;Williams et al, 2008;Dickson and Head, 2009;Heldmann et al, 2012). Models show that snowfall is possible in the mid to high latitudes at higher obliquity (Mischna, 2003;Madeleine et al, 2009), which could then be concentrated into topographic hollows Table 1 Terrain class descriptions from Jones et al (2014) and Putzig et al (2005).…”