Mars was once thought to have a thick, carbon dioxide-rich atmosphere and liquid water, which reacted with rocks to form carbonate minerals. However, missions and spectroscopy have found less carbonate than expected.
As the Curiosity rover climbs Mount Sharp in Gale Crater, it examines rocks from different time periods. A new study analyzing drill samples from a sulfate-rich layer found siderite, an iron carbonate mineral, within these rocky layers.
The discovery of abundant siderite in Gale Crater could provide new insights into Mars’ geologic and atmospheric history. Researchers analyzed an 89-meter section of Gale Crater using data from the Curiosity rover, finding siderite in amounts ranging from 4.8 to 10.5 weight percent, alongside highly water-soluble salts.
Scientists believe the siderite formed under water-limited conditions, driven by water-rock interactions and evaporation processes, shedding light on Mars’ past environment.
The carbonates discovered in Gale Crater have partially decomposed, releasing some carbon dioxide back into the atmosphere, hinting at an ancient carbon cycle on Mars. This finding suggests that carbonate minerals beneath the surface may be hidden by other minerals, making them difficult to detect through near-infrared satellite analysis.
If similar sulfate-rich layers across Mars also contain carbonates, the total stored carbon dioxide would only account for a fraction of what was needed to create a warm, water-friendly atmosphere in the planet’s past. The remaining carbon dioxide might be concealed in other deposits or have escaped into space over time.
Source: Tech Explorist
