The floors of these craters contain very interesting and
enigmatic materials which may contain shallow subsurface ground
ice with varying amounts of a sediment covering (mantle). When
ice is covered with a critical thickness of sediment it is
actually insulated and can survive longer than cleaner exposed
ice. The ablation and sublimation of the ice causes a chaotic
topography to develop with high and low regions. This may
explain the relief seen on the crater floors. The terrain
outside of the craters appears muted because it is most likely
mantled with a dusty icy covering. This region of Mars is
located along the highland/lowland boundary dichotomy. Note:
this THEMIS visual image has not been radiometrically nor
geometrically calibrated for this preliminary release. An
empirical correction has been performed to remove instrumental
effects. A linear shift has been applied in the cross-track and
down-track direction to approximate spacecraft and planetary
motion. Fully calibrated and geometrically projected i