This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element iron. Iron, having the chemical symbol Fe, is among of the most abundant elements on the surface of both Mars and Earth. It is responsible for the red color on the surface of Mars. Regions of highest iron content, shown in red, are concentrated in the area spanning from Utopia Planitia to Amazonis Planitia (right and left sides of the map) and within Acidalia Planitia (just left of center). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. 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.