This image shows an enigmatic ridge within a broad deposit west of Pavonis Mons, oriented roughly radial to the volcano.

The origin of the deposit is uncertain; one possibility is that it formed during an episode of cold-based glaciation in a different Martian climate. In other areas (outside the region shown here) it forms a series of arcuate concentric ridges which may be moraines. The textured appearance shown here of the surface is common in much of the deposit.

The large ridge in the left part of the image appears to have trapped some dust, as it has a smooth, mantled appearance. There are also many wind-blown ripples in the western part of the image. The ridge itself may be due to a volcanic eruption along a fissure system, possibly under ice if Pavonis Mons was once glaciated.

Unfortunately, the mantling at this site has obscured most underlying details of the ridge which could clarify the conditions under which it formed.
Written by: Colin Dundas

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.