The central portion of this image includes a portion of a valley network in Arabia Terra. In lower resolution images, this meander (a bend in a valley) appeared discontinuous - hence its selection as a target for HiRISE. However, at HiRISE resolution the valley is visible throughout its course.

This is a mid-latitude scene where ground ice is believed to be stable relatively near the surface today. The mottled terrain visible throughout the image could be a sublimation texture. Sublimation occurs when ice goes directly to the gas phase. When this happens, the space beneath the subsurface that the ice previously occupied is now empty, allowing the remaining surface to collapse and form the observed texture.

Several of the craters in this scene have flattened appearances, which may have resulted from ice-rich material being driven by gravity into the crater centers.


Written by: Kelly Kolb

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.