The high resolution image shows many small windblown drifts or dunes in the low areas both within the crater and outside on the surrounding terrain. Some portions of the crater's walls have outcrops of bare, layered rock. Large boulders have been dislodged from the walls and have tumbled down the slopes to the crater floor. Many of these boulders are bigger than school buses and automobiles. These polygon formations in Mars' southern polar region resemble those that form in Earth's arctic regions.
Polygons form when the ground freezes and thaws repeatedly over the course of time.
The polygons were photographed at Malea Planum in the far southern regions of Mars. Patches of frost from the retreating south polar ice cap are caught in the cracks making them more visible. Scientists say finding polygons at the Malea Planum indicates that ice is not too deeply buried because only a thin veneer of material appears to have covered the crater at the top of the scene. It has orbited the red planet for a full Martian year, or 26 months. It started collecting extensive data earlier this year.