Malea Patera is one of a group of ancient volcanoes that ring the Hellas impact basin.

This HiRISE image was intended to investigate the nature of the volcanic materials at this location. However, the image was taken in early spring for this location in the southern hemisphere and so the ground is covered with bright frost except for some dark splotches found in discrete patches. This is where the sunlight has penetrated the frost and initiated defrosting around discrete spots.

Clearly something is different about the patches where this defrosting has started before any other locations. One possibility is that these are (frost covered) dark sand dunes that heat up more easily than the surrounding terrain. However, we will need to take a new image in the summer time to really know what is happening here.

Written by: Laszlo P. Keszthelyi

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.