In those drill sites, Curiosity detected deposits containing an iron carbonate material called siderite. According to Ben Tutolo, a University of Calgary associate professor of Earth, Energy, and Environment Studies as well as a NASA Mars Science Laboratory Curiosity Rover team, the data marks a major moment in the search for extraterrestrial life.

A treasure trove of clues from Curiosity reveals that ancient Mars once trapped massive amounts of CO2 in its crust, thanks to surprising concentrations of iron carbonate deep in Gale Crater. By drilling into layers laid down in a vanished lake,