The search for life on Mars goes through Duluth

DULUTH -- Rock samples from Duluth are giving researchers clues as to whether Mars could have sustained life.

Scientists have found several signs that ancient Mars had running water and a warmer climate than it does now. Researchers are investigating why that is.

A new study from the University of Calgary suggests one possible answer: a chemical reaction in iron-rich rocks that releases a lot of hydrogen, causing a greenhouse effect that would have trapped sunlight and warmth in the planet’s atmosphere.

Ben Tutolo is an associate professor of geoscience at the University of Calgary. While working on his doctorate several years ago at the University of Minnesota, he started studying something called serpentinization: a chemical process in which rocks give off hydrogen gas. He took some rock samples from the Duluth Complex rock formation to study this process.

Courtesy / Ben Tutolo via MPR News

Years later, he started studying what this chemical process would have looked like on Mars. Since Mars’ surface is especially iron-rich, he looked for comparable iron-rich rocks on Earth to see how much hydrogen they produced.

“I realized that, actually, these rocks from the Duluth Complex that I'd already sampled, I'd already looked at, look a lot like similar rocks would've looked on Mars,” Tutolo said.

Rocks like this are rare on Earth, but they can be found in Duluth.

What Tutolo and his team found was that the serpentinization process in these rocks generated about five times more hydrogen than normal serpentinization processes on Earth. That would be enough to warm up Mars, making it possible for water to flow – and even possible for the planet to sustain life.

Sometime around 3.5 billion years ago, Mars’ climate changed to be cold and dry. Scientists are still researching what triggered that shift.

“We know that early Mars was warm and wet. We have abundant geological history of flowing water… we have orbiters and rovers on the planet, and they’re not encountering any liquid water,” Tutolo said. “So the question is, how did that transition from warm and wet to cold and dry occur?”

Tutolo is looking into this question as part of the Mars Curiosity Rover team at NASA. The team is studying sediments on Mars to figure out how the transition is recorded in the rock record.