Curiosity, a Mars rover operated by NASA, has collected more evidence supportive of Mars' potential habitability in the distant past. The rover is currently climbing up a mountain and has been collecting samples along the way. Analysis of those samples reveals the uphill region features notable amounts of clay minerals, hermatite, and boron. It's the first time boron has been found by Curiosity. The element is usually discovered where water was previously present.
There is so much variability in the composition at different elevations, we've hit a jackpot, - John Grotzinger, Caltech
Scientists involved with the mission are "impressed by the complexity of the lake environments when clay-bearing sediments were being deposited." Groundwater in the region may have been particularly suitable for bacteria since the water may have been warm and not very acidic.
Grotzinger described this kind of sedimentary basin as a "chemical reactor."
Elements get rearranged. New minerals form and old ones dissolve. Electrons get redistributed. On Earth, these reactions support life. - Grotzinger
As the Curiosity mission has progressed, more signs in favor of Mars' prior habitability have been found.
We're finding different habitable environments as we go along, - Joy Crisp, Mars Science Laboratory