NASA's Curiosity Rover Uncovers Evidence of Ancient Carbon Cycle on Mars

NASA’s Curiosity rover has made a groundbreaking discovery that could change our understanding of Mars’ history and its potential to support life. New research led by Dr. Ben Tutolo, a scientist from the University of Calgary, provides compelling evidence of a carbon cycle in Mars’ ancient past — a vital clue in the search for extraterrestrial habitability.

Carbonate Discovery in Gale Crater Sheds Light on Mars' Climate History

Published in the prestigious journal Science, the study reveals that Curiosity rover's data from three drill sites within Mount Sharp's sulfate-rich layers detected siderite, an iron carbonate mineral. These findings suggest that carbon dioxide was once abundant in the Martian atmosphere, potentially allowing liquid water to exist on Mars' surface.

“The discovery of large carbon deposits in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,” says Dr. Tutolo, PhD, associate professor at the University of Calgary and a participating scientist on the Curiosity Rover team.

Was Ancient Mars Habitable?

This new evidence supports the theory that Mars transitioned from a warm, wet environment to its current cold, arid state due to its gradual atmosphere loss. Siderite formation under a CO2-rich atmosphere implies that the Red Planet was warmer in the past and potentially habitable.

“The broader implications are the planet was habitable up until this time, but then, as the CO₂ that had been warming the planet started to precipitate as siderite, it likely impacted Mars’ ability to stay warm,” Tutolo explains.

Implications for Future Mars Missions and Earth Climate Research

NASA scientists believe that future missions targeting sulfate-rich regions of Mars will be key to confirming these findings and understanding the full scope of carbon sequestration on Mars. This work is also directly relevant to Earth-based climate solutions.

“Learning about the mechanisms of making these minerals on Mars helps us to better understand how we can do it here,” says Tutolo. “Studying the collapse of Mars' warm and wet early days also tells us that habitability is a very fragile thing.”

Earth vs Mars: A Tale of Two Planets

Despite similarities in their early histories, Earth and Mars have evolved in vastly different ways. The research highlights how even slight changes in atmospheric CO₂ can drastically alter a planet’s ability to sustain life.

“The most remarkable thing about Earth is that it’s habitable — and has been for at least four billion years,” Tutolo adds. “Something happened to Mars that didn’t happen to Earth.”