PASADENA, Calif., Feb. 15 (UPI) -- The Spirit rover has found a new class of water-affected rock on Mars, NASA scientists said Tuesday.
"This is probably the most interesting and important rock Spirit has examined," said Steve Squyres of Cornell University, the principal investigator for the rovers.
The rock, which scientists named Peace, contains more sulfate salt than any other rock the rover has discovered.
"Where did the salt come from?" Squyres asked. "We have two working hypotheses we want to check by examining more rocks. It could come from liquid water with magnesium sulfate salt dissolved in it, percolating through the rock, then evaporating and leaving the salt behind. Or it could come from weathering by dilute sulfuric acid reacting with magnesium-rich minerals that were already in the rock. Either case involves water."
The rock is part of an outcropping in the Columbia Hills, which rim Gusev Crater, the vast flat plain where Spirit landed 13 months ago.
"This may be what the bones of this mountain are really made of," Squyres said. "It gives us even more compelling evidence for water playing a major role for altering the rocks here."