From Low to High Channels
This image shows the transition from a regular channel to an inverted channel in Arabia Terra. The channel was once flowing with water that carved down into the bedrock to produce a depression.
As the water flow slowed down, sediment became deposited within the channel that caused it to partially fill up. Over time, the landscape around the channel eroded away faster than the sediments within the channel, leaving behind a portion that now stands above the terrain, called an inverted channel. Why only one section of the channel is inverted while the rest is still a depression is unclear, but may reflect the local topography and hardness of the neighboring materials that only protected the channel in some places.
The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. (The original image scale is 63.1 centimeters [24.8 inches] per pixel [with 2 x 2 binning]; objects on the order of 189 centimeters [74.4 inches] across are resolved.) North is up.
This is a stereo pair with ESP_078924_2120.
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.