HiRISE: Eroding terrain in Arabia Terra

This image, approximately 1.5 x 3 kilometers, shows a sample of eroded Martian terrain in Arabia Terra. At one time this was a flat smooth terrain, but over time it has been eroded (most likely by the wind) forming depressed, low-lying areas where we see many small dunes. The dunes resemble waves in the ocean, whereas in other areas we see small flat-top hills forming. [More at link]