NASA’s curiosity rover discovered evidence of the ancient Mars carbon cycle, bringing scientists closer to answers on whether the planet can support life.
Curiosity watches the track retreat in the distance on April 30, 2023 at a site called Ubajara. This site is where Rover discovered the Siderate. Image credit: NASA/JPL-Caltech/MSSS.
Planetary researchers have long believed that Mars once had a thick carbon dioxide-rich atmosphere and liquid water on the surface of the planet.
That carbon dioxide and water should have reacted with Mars rocks to produce carbonate minerals.
However, to date, rover missions and near-infrared spectroscopy analysis from Mars orbit satellites have not discovered the amount of carbonate on the Earth’s surface predicted by this theory.
“We’ve seen a lot of experience in the world,” said Dr. Benjamin Tutoro, a researcher at the University of Calgary.
“The planet is habitable and shows that the model of habitability is correct.”
Using data collected by curiosity, Dr. Tutoro and his colleagues analyzed the composition of the 89 m stratigraphic section of Gail Crater, which once contained an ancient lake.
They identified high concentrations of iron carbonate minerals called siderelites in layers rich in magnesium sulfate, ranging from about 5% to over 10% by weight.
This was unexpected as orbital measurements had not detected carbonates in these layers.
Given its source and chemistry, the researchers speculate that the Seidelians, formed by the water rock reaction and evaporation, indicate that carbon dioxide has been chemically isolated from the Martian atmosphere to sedimentary rocks.
If the mineral composition of these sulfate layers represents a globally sulfate-rich region, these deposits contain large carbon reservoirs that were previously unrecognised.
The carbonate is partially destroyed by a later process, indicating that some of the carbon dioxide was later returned to the atmosphere, creating a carbon cycle.
“The discovery of abundant siderelites in Gale Crater represents both an astonishing and important breakthrough in understanding Mars’ geological and atmospheric evolution,” Dr. Tutoro said.
Dr. Thomas Bristow, a researcher at NASA’s Ames Research Center, added:
“A mere centimeters below gives us a good idea of minerals that were formed on or near the surface about 3.5 billion years ago.”
Survey results It will be displayed in the journal Science.
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Benjamin M. Tsutoro et al. 2025. Carbonates identified by the curiosity rover show the carbon cycle operating on ancient Mars. Science 388 (6744): 292-297; doi: 10.1126/science.ado9966
Source: www.sci.news
