Map Projected Browse Image
Click on the image for larger version

This image from NASA's Mars Reconnaissance Orbiter shows Gorgonum Basin, one of several large basins within the Terra Sirenum region of Mars. Each basin has light-toned mounds, many of which contain clays.

Scientists think that Terra Sirenum once had a large lake during an epoch called the Late Noachian/Early Hesperian, and each basin filled with sediments. The water within the lake may have altered these sediments to form the clays we now observe from orbit. Ma'adim Vallis, which drains into Gusev Crater where the Spirit rover landed, drained the water from this ancient lake.

Why the basin floors exhibit mounds similar to chaos regions on Mars is unknown, but could be the result of collapse and subsequent erosion within the basins.

This is a stereo pair with http://www.uahirise.org/ESP_046478_1430.

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 26.7 centimeters (10.5 inches) per pixel (with 1 x 1 binning); objects on the order of 80 centimeters (31.5 inches) across are resolved.] North is up.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. 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.