Scientists: Mars minerals left by groundwater, not seas

Stephen Withers
Thursday, 08 March 2007 07:54

Science - Space

Mineral deposits found on Mars by the Opportunity rover were probably due to springs rather than long-evaporated seas, scientists now believe.

A study led by MIT's Jeffrey Andrews-Hanna found the deposits resulted from mineral-rich groundwater that formed shallow pools and then evaporated. On Earth, similar deposits can be found at Lake Eyre (Australia) and White Sands (USA) where natural basins allow water to flow in and then evaporate, leaving behind the salty deposits.

The deposits found by the Opportunity Mars rover are at one of the few locations on the planet where groundwater could reach the surface, explaining why such deep deposits were able to build up in the absence of a basin.

This finding does not rule out the presence of seas or oceans during Mars' early history, but it does provide an explanation for the mineral deposits that squares with observations made from orbit and on the planet's surface.