“The discovery of abundant siderite in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,” Benjamin Tutolo, associate professor at the University of Calgary, Canada, and lead author of the paper, said in a statement.

Scientists using NASA’s Curiosity rover have discovered siderite—an iron carbonate—in the sulfate-rich rocks of Gale Crater, solving a long-standing mystery about Mars’ missing carbonates. This find p

A NASA rover taking rock samples on Mars has uncovered a plentiful mineral that was invisible to orbiters studying the Red Planet from space.