One of the most important processes on present-day Mars is wind. Aeolian (wind-related) features are found in most regions of the planet. This image shows a diverse array of such features: large dunes, small ripples, and dust-devil tracks (the dark, arcing structures on the dunes).

Dust devils form in many parts of Mars, but they are often particularly distinct on sand dunes. One possibility is that the dust devils dislodge a small amount of fine dust, making the color of dark sand more prominent.

Ripples of wind-blown sand form regular patterns. In the simplest case, wind blowing in a constant direction creates evenly spaced straight ripples at right angles to the wind. More complex wind patterns create more complex ripples, and in this scene variations from linear to polygonal to checkerboard patterns are visible.

This image is particularly interesting because of the occurrence of seasonal frost on the south-facing slopes. (The image is in the southern hemisphere, so south faces the pole and gets little winter light). This is particularly apparent in the color swath, as the frost forms pale, purplish patterns. On the dunes, this highlights some of the regular patterns, as the frost forms only on parts of the ripples. The result is an intricately textured pattern of color.


Written by: Colin Dundas

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.