Hydrated minerals as mapped by Mars Express’ OMEGA

This image shows the global distribution of hydrated (water-rich) minerals as discovered by the OMEGA instrument on board ESA’s Mars Express. The map is superimposed on an altitude reference map of Mars built with data from the MOLA instrument on board NASA's Mars Global Surveyor. The red marks indicate the presence of phyllosilicates, the blue ones indicate sulphates, the yellow ones indicate other hydrated minerals.