spacetoday.net: Mars mineral deposits linked to groundwater

Posted: Sat, Mar 10, 2007, 7:19 AM ET (1219 GMT)
Mars Exploration Rover (NASA/JPL)

Mineral salt deposits found on the surface of Mars by one of NASA's Mars rovers may have been created by seeping groundwater rather than an ocean, scientists reported this week. Early in its mission, the Mars rover Opportunity found deposits of sulfur-rich evaporite minerals in the Meridiani Planum of the planet, which to scientists suggested the presence of a liquid water ocean earlier in the planet's history. In a paper published in Thursday's issue of the journal Nature, scientists said the minerals could instead have formed when volcanic activity pushed up groundwater to the surface, where it evaporated and left behind the mineral deposits found by Opportunity. The new results don't preclude the existence of an ocean on the Martian surface in the past, only that the ocean did not extend to the Meridiani Planum region.