Mantling Material on Crater Floor
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Mantling Material on Crater Floor

April 24, 2007

This HiRISE image shows remnants of a mantling deposit on the floor of a crater in the southern highlands of Mars.

The slope up towards the crater rim is visible in the lower right part of the image. The rough, hummocky texture may be related to loss of ice from material that was once ice-rich.

One goal of this image was to investigate the parallel lines that are visible around several of the large hummocks and hills in the image's center. We'd like to determine whether these are layers that are present throughout the rock, or whether they are merely on the surface. In the first case, these may be the expression of buried bedrock layers. However, it is also possible that these are related to the mantling deposits, perhaps representing variations in the mantle.

At high resolution, the lines appear to be small ridges, that are either buried by or composed of the mantling material. In the best exposures, these ridges look like the edges of layers of the mantling material that was draped over the entire region and then eroded off the high places. This suggests the second hypothesis: we are probably seeing variations in the mantle, perhaps due to multiple cycles of material being laid down.

Observation Geometry

Image PSP_001507_1400 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 21-Nov-2006. The complete image is centered at -39.6 degrees latitude, 343.8 degrees East longitude. The range to the target site was 251.3 km (157.1 miles). At this distance the image scale ranges from 25.1 cm/pixel (with 1 x 1 binning) to 100.6 cm/pixel (with 4 x 4 binning).

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 03:40 PM and the scene is illuminated from the west with a solar incidence angle of 76 degrees, thus the sun was about 14 degrees above the horizon. At a solar longitude of 138.9 degrees, the season on Mars is Northern Summer.

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