Bright and Dark Plains near Ganges Chasma
Bright and Dark Plains near Ganges Chasma
ESP_020061_1720  Science Theme: Geologic Contacts/Stratigraphy
This HiRISE image shows a mixture of bright and dark terrain along the plains just West of Ganges Chasma.

The concentration of these bright patches adjacent to an old impact crater suggests that the bright patches could represent ejecta from when the crater formed. This would be an interesting discovery because it would mean that a different unit underlies the surface we now see. Alternatively, much of the plains in this region appear to have a dark surficial cover, probably aeolian debris. Where this darker debris has been removed by the wind, the underlying brighter substrate would be exposed.

Mineralogic information from the CRISM instrument would be very useful for determining if the bright patches contain minerals indicative of water, such as clays, or if they are basalts produced from volcanic eruptions.

Written by: Cathy Weitz  (5 January 2011)
Acquisition date
06 November 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
261.4 km (162.4 miles)

Original image scale range
26.2 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
56°, with the Sun about 34° above the horizon

Solar longitude
176.6°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  12.6°
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Black & white is 5 km across; enhanced color about 1 km
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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:

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. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.