The layers seen in this HiRISE subimage of Echus Chasma are very different from the light-toned, thinly bedded layers HiRISE has observed in deposits seen elsewhere in Valles Marineris.

The HiRISE view of these layers in Echus Chasma shows they are rough, with knobs of rock sticking out through the dust and talus (loose debris) on the slope. This indicates that perhaps these layers are made of different materials than the light-toned deposits, which appear more friable in nature.

These rough layers may be exposures of lavas, or they might just be more resistant forms of sedimentary rocks. The layers are typical of those seen in chasma slopes and crater rims elsewhere on the Martian surface.
Written by: Ross A. Beyer

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.