This observation shows internal layering exposed in a basal section (bottom part) of the polar layered deposits. The south polar layered deposits are composed primarily of water ice with a small amount of dust.

Variations in dust content most likely controls the erosion of the layers. The layers were laid down over a large area near the south pole, probably over the past few million years. They are believed to record recent global climate changes on Mars in much the same way that polar ice in Greenland and Antarctica provide information about varying climatic conditions on Earth.

Several layers appear to be truncated (see subimage) and most likely represent unconformities. Unconformities form when an episode of erosion that removes all or part of a layer is followed by more deposition.

Written by: Maria Banks

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.