This image shows internal layering in the south polar layered deposits exposed on a scarp. The south polar layered deposits are composed primarily of water ice with a small amount of dust. Variations in dust content most likely control the erosion of the layers.

Some layers have an irregular wavy appearance that may have been caused by flow of the ice in the past when the now-exposed ice was still buried. It is currently too cold at the surface in the south polar region of Mars for significant flow to be occurring today. Other layers appear to be converging and some are truncated and may represent unconformities (see subimage). Unconformities form when a previous episode of erosion removes all or part of a layer and is later followed by more deposition.

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 and oscillations on Mars in much the same way that polar ice in Greenland and Antarctica provide information about varying climatic conditions on Earth.
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.