Posted: Wed, Sep 12, 2012, 9:03 AM ET (1303 GMT)
Clay minerals identified on Mars could be formed by processes that don't require the presence of flowing liquid water, scientists reported this week. The discovery of clays in the Martian soil had previously been seen as evidence that liquid water once existed on Mars, but new research reveals that clays found in a Martian meteorite are similar to those found on Earth that are formed from water-rich lava. The thickness of some clay layers seen on mars, in some cases hundreds of meters, could be better explained by a volcanic origin, which would suggest early Mars may have been less habitable than previously thought.
