This image shows what appears to be a degraded alluvial fan at upper left and a dust devil at lower right.

An alluvial fan is deposited by a river flowing out onto a plain; if this feature was formed by water, the activity ceased long ago, based on the density of craters on the fan surface.

The dust devil, on the other hand, is an example of the ongoing processes that continue to shape the surface of Mars.

Written by: Ken Herkenhoff   (7 September 2011)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_023671_2270

Image: NASA/JPL/University of Arizona