Swirls of Rock in Candor Chasma
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Swirls of Rock in Candor Chasma

April 4, 2007

This image shows spectacular layers exposed on the bottom of Candor Chasma, which is a large canyon in the Valles Marineris system.

The floor here is approximately 4 km below the canyon rim. The layers are made of sand- and dust-sized particles that were transported here by either wind or water. This canyon may have been filled to its rim by these sedimentary layers, subsequently eroded away, most likely by the wind. The elongate hills may represent areas of rock that are stronger due to differences in the size of the sedimentary particles, chemical alteration, or both.

One of the most eye-catching aspects of this scene are the intricate swirls that these layers form. Sedimentary rock generally accumulates in horizontal layers. These layers, however, have been folded into the patterns that we see today. Folding of the layers that are exposed here may have occurred due to the weight of overlying sediments.

Understanding the geologic history of this region may provide clues into the history of water on Mars, because these layers may have accumulated in shallow lakes and may have undergone chemical reactions with this water. The presence of certain kinds of chemical reactions between water and rock can release energy that could have sustained habitable oases in these areas.

Observation Geometry

Image PSP_001984_1735 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 29-Dec-2006. The complete image is centered at -6.5 degrees latitude, 283.1 degrees East longitude. The range to the target site was 261.6 km (163.5 miles). At this distance the image scale is 26.2 cm/pixel (with 1 x 1 binning) so objects ~79 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 57 degrees, thus the sun was about 33 degrees above the horizon. At a solar longitude of 157.8 degrees, the season on Mars is Northern Summer.

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