January, 2008: Iron Map
This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma rays from the element iron. Iron, with the chemical symbol Fe, is among the most abundant elements on the surface of both Mars and Earth. It is responsible for the red color on the surface of Mars. Iron concentrations appear overall to be higher, shown in red and yellow, in the northern hemisphere than in the southern hemisphere, shown in blue. The reason for this difference is still unclear, although it may related to leaching and transport of iron from the southern highlands to the northern lowlands. The white sections at the top and bottom of the map represent regions of the planet where obtaining concentration values for iron is more difficult due to large amounts of water ice in the soil. The locations of the five successful lander missions are marked: Viking 1 (VL1), Viking 2 (VL2), Pathfinder (PF), Spirit at Gusev (G), and Opportunity at Meridiani (M). More information about this map can be found in the recent article by Boynton, W. V., et al. (2007), Concentration of H, Si, Cl, K, Fe, and Th in the low- and mid-latitude regions of Mars . You may obtain full resolution versions of this and other elemental maps at http://grs.lpl.arizona.edu/specials/.