Gullies and Boulder Tracks

The formation of gullies on Martian slopes is still under debate. Potential mechanisms include the melting of surface water ice, groundwater outbursts, or dry mass wasting processes (landslides).

This image shows several shallow gully channels with associated debris aprons emanating from a buried layer on the interior of a crater wall. Also visible are many boulders of varying sizes along the wall, with several exhibiting clear tracks from their journey downslope. These tracks can be used to better understand the mass wasting environment on the hill slope and whether there is any connection between the boulders and the gullies.

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. (The original image scale is 25.6 centimeters [10.1 inches] per pixel [with 1 x 1 binning]; objects on the order of 77 centimeters [30.3 inches] across are resolved.) North is up.

The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.