Layers in Echus Chasma Region
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.
Image PSP_002472_1810 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 05-Feb-2007. The complete image is centered at 1.1 degrees latitude, 278.6 degrees East longitude. The range to the target site was 268.8 km (168.0 miles). At this distance the image scale is 26.9 cm/pixel (with 1 x 1 binning) so objects ~81 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel and north is up.
The image was taken at a local Mars time of 03:39 PM and the scene is illuminated from the west with a solar incidence angle of 55 degrees, thus the sun was about 35 degrees above the horizon. At a solar longitude of 178.5 degrees, the season on Mars is Northern Summer.