Fretted Terrain Valley Traverse
NASA/JPL/University of Arizona
Fretted Terrain Valley Traverse
PSP_009719_2230  Science Theme: Glacial/Periglacial Processes


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This observation shows fretted terrain in valleys located in Protonilus Mensae near the crustal dichotomy, the region that separates the Southern hemisphere highlands from the Northern hemisphere lowlands.

Fretted terrain is thought to involve movement of ice-rich material in its formation. The speckled texture of the valley fill (the fretted terrain) is probably due to sublimation, when ice goes directly from a solid to a gas, leaving behind empty space under the soil into which overlying material can collapse.

The linear striations in the valley fill mark the direction of movement. For example, in the valley near the top of the image, the material was moving across the scene (probably to the right based on images from other datasets). Also in this scene, are several small craters in various stages of degradation.

Written by: Kelly Kolb   (17 December 2008)

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Acquisition date:22 August 2008 Local Mars time:15:20
Latitude (centered):42.412° Longitude (East):48.135°
Range to target site:295.4 km (184.6 miles)Original image scale range:59.1 cm/pixel (with 2 x 2 binning) so objects ~177 cm across are resolved
Map projected scale:50 cm/pixel and North is upMap projection:Equirectangular
Emission angle:0.4° Phase angle:46.0°
Solar incidence angle:46°, with the Sun about 44° above the horizon Solar longitude:116.4°, Northern Summer

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