The new Mars rover Curiosity is on its way to the red planet, but that doesn’t mean its brother still on the planet is slacking off. The Mars rover Opportunity continues to truck around the Martian landscape just as it has since 2004, collecting data and transmitting it back to Earth. At the American Geophysical Union’s conference in San Francisco on Wednesday, NASA announced that Opportunity found a mineral vein on Mars that was likely deposited by water.
NASA describes “bright veins of a mineral” occurring on an apron around a portion of the rim of Endeavour Crater. Researchers have nicknamed the vein most closely observed by Opportunity “Homestake” and it and its kin are unlike any other veins Opportunity has observed on the planet’s surface since it’s been there. The spectrometer on Opportunity’s arm identified a ratio of calcium and sulfur that points to relatively pure calcium sulfate and the multi-filter data from the rover’s Panoramic Camera suggests the form of this calcium sulfate is gypsum. Calcium sulfate is a big deal, because its high concentration could mean less acidic and more hospitable water conditions than what is suggested by other sulfate deposits previously observed on Mars. The gypsum was likely formed by groundwater coming up through the planet’s crust, which carried up calcium sulfate formed when calcium from volcanic rocks combined with sulfur from other volcanic rocks or volcanic gas.
In addition to suggesting that there was not only water on Mars but water amenable to more types of life than previously thought, researchers think it could explain other gypsum observed on Mars. Orbital observations found a dune field of gypsum sand on northern Mars that looks like those in White Sands National Monument in New Mexico, but the origins of those dunes were previously unknown. Basically, as Steve Squyres – principal investigator for Opportunity – puts it, the calcium sulfate veins discovered by the rover tell “a slam dunk story that water flowed through underground fractures in the rock. […] [gypsum isn’t] uncommon Earth, but on Mars, it’s the kind of thing that makes geologists jump out of their chairs.”