This false-color subframe of an image from the High Resolution Imaging
Science Experiment camera on NASA's Mars Reconnaissance Orbiter shows the
north polar layered deposits at top and darker materials at bottom,
exposed in a scarp at the head of Chasma Boreale, a large canyon eroded
into the layered deposits.
The polar layered deposits appear red because of dust mixed within them,
but are ice-rich as indicated by previous observations. Water ice in the
layered deposits is probably responsible for the pattern of fractures seen
near the top of the scarp. The darker material below the layered deposits
may have been deposited as sand dunes, as indicated by the crossbedding
(truncation of curved lines) seen near the middle of the scarp. It appears
that brighter, ice-rich layers were deposited between the dark dunes in
places. Exposures such as these are useful in understanding recent climate
variations that are likely recorded in the polar layered deposits.
NASA's Jet Propulsion Laboratory, a division of the California Institute
of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for
NASA's Science Mission Directorate, Washington. Lockheed Martin Space
Systems, Denver, is the prime contractor for the project and built the
spacecraft. The High Resolution Imaging Science Experiment is operated by
the University of Arizona, Tucson, and the instrument was built by Ball
Aerospace and Technology Corp., Boulder, Colo.
