This image shows an area of layered deposits in Candor Chasma. Here, sheets and dunes of dark-toned sand cover the light-toned, layered bedrock. Accumulations of dark sand accentuate bedding within the light-toned bedrock, giving some areas a zebra striped pattern.
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.
Written by: Chris Okubo (15 December 2010)
More info and image formats at http://hirise.lpl.arizona.edu/PSP_003830_1740
Image: NASA/JPL/University of Arizona