This scene in the Acidalia Planitia contains a variety of features, the most prominent of which are two mesas (hills).

Several craters in the scene have bright material extending outward from their bottom left rims. These are wind streaks that mark the most recent dominant wind direction. The wind blows material out of the craters onto the adjacent plains.

At the bottom of the image are a cluster of craters. These might be secondary craters, which formed when ejecta from one impact hit the surface moving fast enough to create more craters. Secondary craters are identified partly by their occurrence in clumps and similar relative ages because all secondary craters from a single impact form at the same time.

Written by: Kelly Kolb

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.