ICE CAVES ON MARS

Caves on planet Mars could potentially contain water ice deposits. Here, I assess the physical processes responsible for the growth and preservation of spelean ice formations on Mars.

Martian caves are situated in environments where phase transitions of water are only by sublimation, and the predominant type of cave ice is expected to be perennial hoarfrost that slowly grows in supersaturated cavities. Crystal growth at martian ambient conditions is slower than on Earth, but far more time is available for hoarfrost to grow continually, and cave hoarfrost deposits could be massive.

The role of cave microclimates for maintaining ice bodies is evaluated comparatively (Earth versus Mars). Free and forced convection transport less sensible heat than in the denser terrestrial atmosphere. Cooling through sublimation is also expected to be far weaker in Martian caves than in terrestrial caves. Hence, the cooling of ice deposits by flow through the cave, often a crucial factor in terrestrial ice caves, is insignificant on Mars, which limits the geographic extent where ice caves (caves in bedrock that host ice) can be expected.