This image includes a crater that has been heavily influenced by later geologic processes. First of all, terrain-altering or -burying processes have eliminated much of the pattern of ejecta that surrounds fresh craters. The crater also appears fairly flat-floored with short walls (not very deep) for its size, indicating material has filled it in. These modifying effects may be due to deposition and activity of ice-rich or other mantling sediments deposited at some point in the past.
Finally, the crater clearly exhibits gullies starting on its northern wall and extending to its center. The arc-shaped ridge inside the southern edge of the crater, partially buried by the filling material, is particularly curious - it could be a wind-caused or other accumulation of crater-fill material.
One of the rationales for acquiring an image of this location is to investigate the relationship between these features; HiRISE's full resolution can provide better details of the terrain. Written by: Patrick Russell (1 February 2011) More images