Texas A&M Study Hints at Ancient Life on Mars from Rover Samples
COLLEGE STATION, Texas — A new study co-authored by Texas A&M University geologist Dr. Michael Tice suggests that ancient Martian rocks examined by NASA’s Perseverance rover might contain chemical signatures of microbial life.
The research, published in the journal Nature, focuses on the Bright Angel formation in Jezero Crater, a region named after locations in Grand Canyon National Park due to its light-colored rocks. This area is rich in mudstones that contain oxidized iron, phosphorus, sulfur, and organic carbon — all of which could have provided energy for early microorganisms.
“When the rover entered Bright Angel and started measuring the compositions of the local rocks, the team was immediately struck by how different they were from what we had seen before,” said Tice, who is also a geobiologist and astrobiologist. “They showed evidence of chemical cycling that organisms on Earth can take advantage of to produce energy.”
The Bright Angel formation consists of sedimentary rocks formed by water, suggesting a once dynamic environment. Using tools like the SHERLOC and PIXL spectrometers, scientists detected organic molecules that signify possible biological activity.
Among notable findings are tiny nodules enriched in ferrous iron phosphate and iron sulfide, which typically form in low-temperature and water-rich environments. “It’s not just the minerals, it’s how they are arranged in these structures that suggests that they formed through the redox cycling of iron and sulfur,” Tice explained.
The SHERLOC instrument identified a Raman spectral feature called the G-band, indicative of organic carbon in several rocks. Notably, the strongest signals came from an area called “Apollo Temple,” where specific minerals were found in abundance.
“This co-location of organic matter and redox-sensitive minerals is very compelling,” Tice noted. “It suggests that organic molecules may have played a role in driving the chemical reactions that formed these minerals.”
The study presents two scenarios regarding the origin of these organic molecules: one might be abiotic processes driven by geology, while the other could involve ancient microbial life. Although some features of the rocks might be explained by geological processes, Tice stated that it’s being considered that these were potentially produced by living organisms more than three billion years ago.
Perseverance has collected a core sample from the Bright Angel formation, which is now stored for a potential return mission to Earth. “Bringing this sample back to Earth would allow us to analyze it with instruments far more sensitive than anything we can send to Mars,” Tice said.
Dr. Tice emphasized the significance of these findings, explaining they meet NASA’s criteria for potential biosignatures that need further investigation to determine their origins. “What’s fascinating is how life may have been making use of some of the same processes on Earth and Mars at around the same time,” he added. “It’s a special and spectacular thing to be able to see them like this on another planet.”
