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 (9 November 2011)
This is a stereo pair with ESP_014127_1420 .
More info and image formats at http://hirise.lpl.arizona.edu/ESP_020786_1420
Image: NASA/JPL/University of Arizona