More amazing Mars news out of the University of Arizona.
UA planetary geologist James Dohm and co-authors report that the Gamma Ray Spectrometer onboard NASA's Mars Odyssey found evidence that oceans once covered about a third of ancient Mars.
The instrument's data on potassium, thorium, and iron, indicates where the elements would have been eroded from the highlands and deposited in a large sea early in the planet's history.
The map at right shows high potassium concentrations in yellow and red in lowlands, indicating possible ocean basins. [credit, Univ. of Arizona]