Colorful Fractured Bedrock in Ritchey Crater
Colorful Fractured Bedrock in Ritchey Crater
ESP_029542_1510  Science Theme: Impact Processes
HiRISE has imaged Ritchey Crater several times before (see ESP_011635_1510, ESP_025797_1515 and ESP_026931_1510 for some examples), but its interesting features extend beyond the range of a single—or even several—HiRISE footprints. HiRISE now has complete coverage over the central uplift in this 80-kilometer diameter crater.

Central peaks form in large impact craters during the impact event, when the crater floor rebounds after the initial compression. These central uplifts make attractive targets for HiRISE both because they tend to be relatively dust-free, and because as a consequence of their formation, they tend to bring up to the surface rocks that come from greater depths.

In the case of Ritchey Crater, these exposed rocks appear to be chunks of fractured bedrock, possibly of plutonic origin. (Meaning igneous rock that solidifies below the surface). Visible in enhanced colors here are some of these bedrock blocks. The dark, ridgelike lines that cut across the colorful blocks may be dikes, formed when molten rock forced its way into pre-existing linear fractures in the surrounding rock. Alternatively, the ridges could be the result of minerals precipitating out of groundwater flowing through the fractures.

Written by: Nicole Baugh  (5 December 2012)

This is a stereo pair with ESP_029964_1510.
Acquisition date
14 November 2012

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
255.8 km (159.0 miles)

Original image scale range
53.4 cm/pixel (with 2 x 2 binning) so objects ~160 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
206.7°, Northern Autumn

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  13.4°
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non-map           (121MB)

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Full resolution JP2 download
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Black & white is 5 km across; enhanced color about 1 km
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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.