"We compared Gamma Ray Spectrometer data on potassium, thorium and iron above and below a shoreline believed to mark an ancient ocean that covered a third of Mars' surface, and an inner shoreline believed to mark a younger, smaller ocean," said University of Arizona planetary geologist James M. Dohm, who led the international investigation.
© University of Arizona
This 3D map superimposes gamma-ray data from Mars Odyssey's Gamma-Ray Spectrometer onto topographic data from the laser altimeter onboard the Mars Global Surveyor. The red arrow indicates the shield volcanoes of Elysium rise in northern Mars, seen obliquely to the southeast. Blue-to-violet colors at the Elysium rise and highlands stretching to the foreground of the map mark areas poor in potassium. Red-to-yellow colors mark potassium-rich sedimentary deposits in lowlands below the Mars Pathfinder landing site (PF) and Viking 1 landing site (V1).
This 3D map superimposes gamma-ray data from Mars Odyssey's Gamma-Ray Spectrometer onto topographic data from the laser altimeter onboard the Mars Global Surveyor. The red arrow indicates the shield volcanoes of Elysium rise in northern Mars, seen obliquely to the southeast. Blue-to-violet colors at the Elysium rise and highlands stretching to the foreground of the map mark areas poor in potassium. Red-to-yellow colors mark potassium-rich sedimentary deposits in lowlands below the Mars Pathfinder landing site (PF) and Viking 1 landing site (V1).
"Our investigation posed the question, Might we see a greater concentration of these elements within the ancient shorelines because water and rock containing the elements moved from the highlands to the lowlands, where they eventually ponded as large water bodies?" Dohm said.
