Enigmatic Canyon Dunes

This image shows a cross-section of ancient canyon systems in east Coprates Chasma, and displays several orders and generations of wind-driven dunes and ripples, also called bedforms. Some areas display more modern bedforms, often termed mega-ripples, which have likely been active over long timescales and have migrated in the recent past.

Other areas along the canyon wall have larger bedforms that show a very different appearance. Although they have a spacing that would make them similar to typical Martian sand dunes, many display superposed craters, indicating they have not migrated for a very long time, possibly hundreds of thousands of years.

The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. (The original image scale is 53.0 centimeters [20.9 inches] per pixel [with 2 x 2 binning]; objects on the order of 159 centimeters [62.6 inches] across are resolved.) North is up.

This is a stereo pair with PSP_009143_1645.

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