Layered Bedrock in Candor Chasma

In the Northern part of the scene, the bedrock has been eroded into steep, craggy cliffs. Some sections of these cliffs are covered by triangular-shaped debris fans that are intermediate in color between the dark-toned sand and light-toned bedrock.These fans may contain a mix of light-toned bedrock that has crumbled away from the surrounding cliffs and wind-blown sand and dust.

The surfaces of some fans are dissected by gullies, which most likely formed through dry avalanching. The bottoms of the gully channels are often darker in tone than the surrounding fan surface. This may be due to accumulations of wind-blown sand in the gully floor. The subimage shows a clear example of a gullied fan from the northern portion of the scene.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo.

Originally released October 10, 2007