The latest research by a team of scientists with Dr. Ben Tutolo of the University of Calgary, published in the journal Science, provides evidence of an ancient carbon cycle on Mars. Analysis of rock samples from Gale crater, collected by the Curiosity rover, revealed the presence of siderite, a carbonate mineral containing iron. The discovery suggests that more than 3.5 billion years ago, Mars’ atmosphere was rich in carbon dioxide and could have supported liquid water existing on the planet’s surface.
Significance of the discovery of siderite
Siderite, or iron(II) carbonate, is formed by the reaction of carbon dioxide with water and iron-containing minerals. Its presence in the rocks of Gale crater indicates an active carbon cycle in Mars’ past. The research team, analyzing data from three drilling sites explored by Curiosity in 2022 and 2023, found evidence of siderite in sulfate-rich layers on the slope of Mount Sharp. This discovery is significant because previous models suggested the presence of carbonates on Mars, but direct evidence of their existence was lacking.
Implications for climate and the possibility of supporting life
The presence of siderite suggests that Mars’ ancient atmosphere contained enough CO₂ to maintain temperatures that allowed for existence of liquid water. However, geochemical processes leading to the formation of siderite may have contributed to the gradual removal of CO₂ from the atmosphere, resulting in the cooling of the planet and the loss of conditions conducive to life. Dr. Tutolo stresses that the carbon cycle on Mars was unsustainable – more CO₂ was sequestered in rocks than was released back into the atmosphere. This may have challenged the planet’s ability to maintain conditions that would support life.
Applying Martian research to Earth
Research on Mars’ carbon cycle is also relevant to processes occurring on Earth. Dr. Tutolo and his team are using the acquired knowledge to develop methods to sequester CO₂ by converting it into carbonate minerals. Understanding the mechanisms for the formation of such minerals on Mars can help develop technologies to remove CO₂ from the planet’s atmosphere, which is important in the fight against climate change.
The discovery of siderite on Mars opens new avenues of research into the planet’s climate history and potential ability to support life. The team of scientists plans to continue analyzing the samples collected by Curiosity to better understand the geochemical processes that took place on Mars. Further research may also provide valuable information on the possibility of using similar processes to sequester CO₂ on Earth.
Sources: EurekAlert!, ScienceDaily, science.ucalgary.ca / Fot.: geekweek.interia.pl
