South Polar Residual Cap Margin (extra-detail mgnf; MULTISPECTRUM - elab. Lunexit)

In this extra-detail mgnf one can see fractures in the Residual Cap ice near the margin and, farther in, circular depressions that, in some places, appear to have coalesced.
These depressions constitute what is called "Swiss Cheese Terrain" and it's fairly easy to see why. The Swiss cheese terrain is created when the CO2 goes directly from the solid state (ice) to a gaseous state (the more familiar CO2 gas) as temperatures warm during South Polar Summer.
Swiss Cheese Formation may also be linked in a complicated way to the behavior of major Martian Dust Storms.

Images like these, taken before and after dust storm events, can aid our understanding of that complicated relationship.