Curiosity Mars rover found Siderite on the red planet

NASA’s Curiosity Mars rover has discovered a key mineral that may help solve one of the long-standing mysteries of the Red Planet: what happened to Mars’ thick, ancient atmosphere. The mineral, called siderite, could provide vital clues about how the Martian climate evolved and how the planet lost its ability to support surface water.

Key Highlights

• For years, scientists have believed that early Mars had a dense, carbon dioxide-rich atmosphere, allowing for the presence of liquid water on its surface. According to this theory, carbon dioxide and water should have chemically interacted with Martian rocks, forming carbonate minerals. However, prior analyses — from rover missions and orbiting satellites — failed to detect the expected quantities of these carbonates on Mars’ surface.

• That changed when Curiosity, which has been exploring Gale Crater since its landing in 2012, drilled rock samples at three different sites in 2022 and 2023. Within these ancient sedimentary rocks, the rover identified siderite, an iron carbonate mineral.

• The presence of siderite, which forms under specific geochemical conditions, indicates that billions of years ago, Mars likely had a thicker atmosphere rich in carbon dioxide. This atmospheric CO₂ would have acted as a greenhouse gas, warming the planet enough to allow stable bodies of liquid water — a key ingredient for life — to exist on the surface.

• On Earth, carbon dioxide plays a central role in regulating climate, and its influence is similarly significant on both Mars and Venus. This discovery strengthens the case that Mars once had a more Earth-like environment, increasing the potential that it could have supported microbial life in the distant past.

Source: NASA