NASA’s rover Curiosity discovered a mineral called siderite on Mars, which can only form from carbon settling from the atmosphere.

During its analysis at Gale Crater on Mars, NASA’s “Curiosity” rover identified a mineral named ‘siderite,’ which can only form from carbon settling from the atmosphere. This discovery indicates that there was an active carbon cycle on Mars billions of years ago, suggesting that the planet may have had conditions conducive to life at one point. The siderite discovery was made during X-ray diffraction analyses conducted by the Curiosity rover with the Chemistry and Mineralogy (CheMin) instrument between 2022 and 2023. Data obtained showed that high-purity crystalline siderite was found at three out of the four drilled points.

The formation of siderite suggests that Mars’s atmosphere once contained high levels of carbon dioxide. This implies that conditions for long-term presence of liquid water on the ancient Mars surface were met.

These findings of liquid water presence align with other geological evidence indicating the presence of lakes and even oceans on the planet’s surface in the past. Benjamin Tutolo, a geochemist from the University of Calgary, mentioned that this discovery supports existing scientific models regarding Mars’ habitability. Previous rover and satellite-based research had found limited evidence of carbonate minerals. However, scientific models had predicted that such minerals should be widespread on the Martian surface. This discovery not only confirmed the expected presence of carbonate minerals but also helped explain why they had not been found before. Researchers highlighted that this finding could potentially change the methods of searching for carbon minerals on Mars.