Craters filled with sediment and ice
Like many other impact craters in the southern highlands, these three craters show typical rims that have already been smoothed out by erosion, as well as shallow and fairly flat crater floors, indicating that they are filled with sediment. Parts of the crater walls seem to have 'melted' and sunk into the centre of the crater depression, and numerous wide gullies cut through the slopes. Particularly striking are the linear structures in the northernmost crater (lower right in the color image, color-coded terrain model, anaglyph). Its surface morphology resembles that of terrestrial block or debris glaciers, which are common in alpine and polar regions.
This typical flow structure was formed when a mixture of debris and ice from a glacier in the crater flowed downhill to the centre of the crater triplet at a breakthrough in the inner crater rim. The debris traces the movements of the plastic ice flow in the subsurface. This is particularly visible on the colour-coded terrain model. The dark patch in the largest crater represents a small accumulation of dark sands, which form numerous and quite impressive dune fields elsewhere on Mars.