This image shows layering at the base of 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.

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.

Some of the layers have an irregular or wavy appearance. This may have been caused by the flow or deformation of the ice at some point in the past, in addition to uneven erosion. A few layers also appear to be converging or to be truncated (center of image). These are called unconformities. Unconformities form when an episode of erosion removes all or parts of existing layers and is later followed by more deposition. Surface fractures, channels, knobs and other features, along with the obscuration of layer contacts, point to a comicated recent history, but also make it difficult to characterize indiviual layers.
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.