This observation shows a wrinkle ridge in the Solis Planum, a region of Mars that is a high-elevation volcanic plain located south of the Valles Marineris canyon system and east of the Tharsis volcanic complex. In the Solis Planum, wrinkle ridges are typically spaced apart roughly 40 kilometers (25 miles).
Wrinkle ridges are linear to arcuate positive relief features and are often characterized by a broad arch topped with a crenulated ridge. These features have been identified on many bodies such as the Moon, Mercury, and Venus. On Mars, they are many tens-to- hundreds of kilometers long, tens of kilometers wide, and have a relief of a few hundred meters. Wrinkle ridges are most commonly believed to form from horizontal compression or shortening of the crust due to faulting and are often found in volcanic plains.
Wrinkle ridges commonly have asymmetrical cross sectional profiles and an offset in elevation on either side of the ridge. The ridge in this image ( see subimage ) appears to have a steeper southeast facing slope and a more gentle northwest facing slope. Some layering is also apparent in the ridge. Large dunes border the ridge to the north.
The reddish colors visible in the color image most likely indicate the presence of dust (or indurated dust). Written by: Maria Banks (14 January 2008)
More info and image formats at http://hirise.lpl.arizona.edu/PSP_006494_1535
Image: NASA/JPL/University of Arizona