This false-color infrared image was taken by the camera system on the
Mars Odyssey spacecraft over part of Ganges Chasma in Valles Marineris
(approximately 13 degrees S, 318 degrees E). The infrared image has been
draped over topography data obtained by Mars Global Surveyor. The color
differences in this image show compositional variations in the rocks exposed
in the wall and floor of Ganges (blue and purple) and in the dust and sand
on the rim of the canyon (red and orange). The floor of Ganges is covered by
rocks and sand composed of basaltic lava that are shown in blue. A layer
that is rich in the mineral olivine can be seen as a band of purple in the
walls on both sides of the canyon, and is exposed as an eroded layer
surrounding a knob on the floor. Olivine is easily destroyed by liquid water,
so its presence in these ancient rocks suggests that this region of Mars has
been very dry for a very long time. The mosaic was constructed using
infrared bands 5, 7, and 8, and covers an area approximately 150 kilometers
(90 miles) on each side. This simulated view is toward the north.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey
mission for NASA's Office of Space Science, Washington, D.C. The thermal
emission imaging system was provided by Arizona State University, Tempe.
Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the
project, and developed and built the orbiter. Mission operations are
conducted jointly from Lockheed Martin and from JPL, a division of the
California Institute of Technology in Pasadena.
Credit: NASA/JPL/Arizona State University