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The layers seen in the 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.

This HiRISE image is PSP_002472_1810.

Observation Geometry
Acquisition date: 2 February 2007
Local Mars time: 3:39 PM
Degrees latitude (centered): 1.1 °
Degrees longitude (East): 278.6 °
Range to target site: 268.8 km (168.0 miles)
Original image scale range: 26.9 cm/pixel (with 1 x 1 binning) so objects ~81 cm across are resolved
Map-projected scale: 25 cm/pixel and north is up
Map-projection: EQUIRECTANGULAR
Emission angle: 7.6 °
Phase angle: 62.4 °
Solar incidence angle: 55 °, with the Sun about 35 ° above the horizon
Solar longitude: 178.5 °, Northern Summer

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, is the prime contractor for the project and 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 and Technology Corp., Boulder, Colo.