NASA’s Curiosity rover has made a major discovery that adds to growing evidence that Mars once had a much warmer and wetter climate, potentially capable of supporting life. Scientists have identified siderite, an iron carbonate mineral, in rock samples collected by the rover from three sites in Gale Crater between 2022 and 2023.
The presence of siderite suggests that Mars once had a thick atmosphere rich in carbon dioxide — a greenhouse gas crucial for trapping heat and sustaining surface water. This discovery supports longstanding theories that the Red Planet was once home to large lakes or even oceans.
“This is a key breakthrough in understanding Mars’ climate history,” said Benjamin Tutolo, a geochemist at the University of Calgary and lead author of the study published in Science. “Siderite forms under specific conditions — in water, and in the presence of a carbon dioxide-rich atmosphere. Finding it in such concentrations points to a very different Martian environment billions of years ago.”
Until now, evidence of carbonate minerals like siderite on Mars has been sparse, despite models predicting their widespread presence. Curiosity’s onboard instruments found siderite concentrations of up to 10.5% by weight in rock samples drilled 1.2 to 1.6 inches (3 to 4 centimeters) deep.
The sedimentary rocks in Gale Crater, including sandstones and mudstones, are believed to have formed around 3.5 billion years ago when the crater was likely a lakebed. Scientists believe that, as Mars’ thick atmosphere thinned over time, carbon dioxide became locked in the planet’s crust through geochemical reactions, forming carbonate minerals.
“These findings help address one of the great puzzles in Mars research: where did all the carbon dioxide go?” said Edwin Kite, a planetary scientist at the University of Chicago and co-author of the study. “Mars has a thin atmosphere today, but all signs point to a much thicker one in the past. Discovering significant stores of carbon-rich minerals offers a new clue.”
Unlike Earth, Mars does not have active plate tectonics, which play a crucial role in recycling carbon through volcanic activity. This means carbon dioxide that was once in the atmosphere may have been sequestered into rock and never released again — a key insight into the loss of Mars’ habitability.
Tutolo emphasized that the Martian carbon cycle was likely “imbalanced,” meaning more carbon dioxide was removed from the atmosphere than re-emitted. “This imbalance may have played a critical role in Mars’ shift from a habitable world to the cold, dry planet we see today,” he said.
Researchers believe similar rock formations across Mars may also contain siderite, suggesting that a substantial portion of the planet’s ancient carbon dioxide is hidden beneath the surface. This discovery not only deepens our understanding of Mars’ climate evolution but also provides valuable data for future exploration and the search for past life.
News Source: www.reuters.com
Dwayne Paschke is an experienced news reporter and media professional, currently working as a senior news analyst for a private media organization based in Toronto, Canada. With years of experience in journalism, he brings a wealth of knowledge to his role, where he contributes to Los Angeles Headlines by providing accurate and comprehensive coverage of significant news stories.
