The Dune Sea of Ganges Chasma

This image is at the eastern edge of a very large deposit of wind-blown dust that occupies Ganges Chasma.

This thick deposit surrounds hills and mesas that rise up through it. We can tell from the patterns that the wind here is primarily blowing from east to west. There is a large cone-shaped hill whose eastern toe is surrounded by a dune crest, but its western toe -- and a lane that stretches off the image frame -- is clear of this dust deposit.

High-standing features like this might cause the wind to flow around it in such a way as to leave a cleared area that is similar to a wake behind a boat.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.