With humans eying Mars as the first possibility for extraterrestrial settlement, water is a pretty big deal (even though there is none, currently). However, NASA’s Curiosity rover recently happened upon some mineral veins atop some Martian mountains, and they’re evidence of some of the most recent fluid movement ever found on Mars. Some of them, researchers say, even look like tasty confections (they aren’t, though).
“Some of them look like ice-cream sandwiches: dark on both edges and white in the middle,” said Linda Kah, a Curiosity science-team member at the University of Tennessee, Knoxville. “These materials tell us about secondary fluids that were transported through the region after the host rock formed.”
The veins, found on Mount Sharp, form when fluids move through cracked rocks and leave behind minerals. Though Curiosity has found brightly colored veins of minerals on Mars before, these darker ones remain a mystery and provide opportunity to learn more about Mars’ history. Scientists do know, however, that these veins were formed later than the wet environmental conditions that formed lake-bed deposits the rover examined at the mountain’s base.
The area is called “Garden City,” and it’s located about 39 feet above the “Pahrump Hills,” the outcrop that forms the center of Mount Sharp. Curiosity spent about six months exploring the first 33 feet of Pahrump Hills, analyzing mud rocks and other such structures in order to find appropriate drilling sites.
“We investigated Pahrump Hills the way a field geologist would, looking over the whole outcrop first to choose the best samples to collect, and it paid off,” said David Blake of NASA’s Ames Research Center.
What NASA is finding is that moving just a bit in elevation yields drilling results with distinctly different chemical compositions. The first, “Confidence Hills,” had the most clay minerals and hematite, both of which commonly form under wet conditions. The second, “Mojave,” had the most jarosite, an oxidized mineral containing iron and sulfur that forms in acidic conditions. A third site, “Telegraph Peak,” contained practically none of the above minerals, but did have ample concentrations of silica in different forms. Drilling has not yet begun at Garden City.
In the mean time, engineers are working on ways to avoid short circuiting to Curiosity’s drill, which has happened several times when using percussive force. The drill has both percussive and traditional rotary capabilities, though percussion is more effective at turning rock into powder for analysis.