This map of Mars shows relative locations of three types of findings related to salt or frozen water, plus a new type of finding that may be related to both salt and water.
Shallow subsurface water ice found by the Gamma Ray Spectrometer and Neutron Spectrometer on NASA's Mars Odyssey orbiter is depicted in colors signifying concentrations.
The presence of hydrogen, shown in blue, signifies higher concentrations of water ice.
The white squares mark locations of impact craters in the northern hemisphere which exposed water ice close to the surface. Red squares mark locations where the Thermal Emission Imaging System on Mars Odyssey has found deposits of chlorite may have resulted from evaporation of salty water.