In its slow ascent up Mount Sharp, NASA’s Curiosity Rover has stumbled upon a mystery fit for the robot’s name: silica. Lots and lots of silica. And the discovery may shape our understanding of the Red Planet’s geologic past, including whether life could have lived there.

Silicon is one of the most abundant elements on Earth, but we hadn’t detected high concentrations of silica minerals on Mars until seven months ago, when Curiosity approached “Marias Pass,” a contact zone between two Martian rock units located near the base of Mount Sharp. It was here that the rover’s laser-firing ChemCam instrument first ID’d sediments chock full of silica, with concentrations of up to 90 percent. The discovery was so surprising that Curiosity’s science team made the rare decision to turn the rover around and hunt for more.

After drilling a few holes and performing elemental and mineral measurements over a period of four months, Curiosity was able to confirm silica enrichment in several different locations. To Martian geologists, this is fascinating, because not only do silica hotspots hint at watery environments, they can tell us what those environments were like.

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