Rare Mars Rock Holds Clue to earliest Water

Crafty detective work based on data from NASA's Mars rover Spirit has uncovered huge amounts of a rare type of Martian rock that adds more proof that the red planet may have harbored liquid water in the ancient past.The rock projection is rich in carbonate minerals and was found in the Columbia Hills, an "island" of low hills at Spirit's Gusev crater home on Mars. Spirit visited the projection in 2005, before it got permanently stuck in its current Martian resting spot.

Carbonates are minerals that enclose carbon dioxide and form readily in the presence of water. So, if the conditions were such that carbonate-bearing rocks were able to form, this would propose that at one point, water – and possibly an environment favorable to primitive life – was likely present in the region."Carbonate forms as a rain product from water, so there has to be water around for them to form in the first place," the study's lead author Richard Morris, a planetary scientist at NASA's Johnson Space Center in Houston, Texas.

Until now, geologic clues for the presence of carbonates on the Martian surface have been comparatively scarce. In contrast, carbonate-rich rocks are plentiful on Earth, where liquid water abounds. The discovery of the carbonate-rich projection came as a surprise to researchers, since plenty of rocksthat did not contain carbonates were previously found in the surrounding area.