A UCalgary scientist studies the geology of Mars in search of signs that the planet could have once supported life | New

Rocks on the surface of Mars could offer telling clues as to whether the Red Planet was once habitable enough to support life.

To find out, the Canadian Space Agencyas part of the NASA-led program Mars Science Lab Missionis funding a three-year study by Dr. Benjamin Tutolo, PhD, associate professor in the Department of Geosciences in the Faculty of Science.

Tutolo will study the geological records of Mars dating back around 3.5 billion years by examining the layers of sediment currently being explored by the Curiosity robotic rover as it collects rock and soil samples from the surface of Mars.

Ben Tutolo

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“Our goal is to impose constraints on whether Mars was habitable,” says Tutolo. “And if Mars was habitable, then we can wonder if it actually evolved life.”

Tutolo and his research team will use data collected by Curiosity as it slowly climbs Mount Sharp. The mountain sits in the center of Gale Crater where Curiosity landed about 10 years ago.

Since May 1, 2022, Curiosity traveled a distance 27.8 kilometers on the Martian surface, according to NASA.

The rover is equipped with several analyzers capable of determining the chemistry and mineralogy of rocks or the ground surface of Mars. Its Canadian-made instrument, the Alpha Particle X-Ray Spectrometer, analyzed 1,211 samples and returned 2,659 results to Earth.

To help interpret what Curiosity sees on Mars, Tutolo and his team will experiment in his lab, run numerical models on a computer, and conduct field research in British Columbia.

The team includes collaborators from the University of Calgary in the Department of Geosciences: Professor Dr. Steve Larter, PhD, and Associate Professor Dr. Rachel Lauer, PhD.

Other participants include an undergraduate student from UCalgary (working on a project this summer), a master’s student who will start in September, and a postdoctoral researcher who will be hired soon.

Anaerobic chamber in the Tutolo laboratory

Tutolo will use this anaerobic chamber in his three-year study.

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Team examining geological transition recorded in rocks

The goal of the team’s research is to study the geological transition from the oldest lake sediments in the deepest part of the Gale crater – where Curiosity began its exploration – to the younger layers of sediments deposited in the crater and which formed Mount Sharp about 3.5 billion years ago.

Tutolo says geological evidence shows that the oldest rocks in the crater come from a “fluviolacustrine environment,” a river-fed lake that contained liquid water.

In contrast, younger sediments from Mount Sharp contain salts of magnesium sulfate, such as Epsom salt used to relax muscles and relieve pain. These salts are extremely soluble, so their precipitation involves the evaporation of almost all the water from a solution to produce the salts.

“We think it must have been drier on Mars to precipitate these minerals. What we are exploring is how this transition is recorded in the rocks,” says Tutolo.

Additionally, the UCalgary team is conducting field research in the Basque Lakes near Cache Creek, British Columbia. These magnesium sulfate lakes – which are rare on Earth – actively precipitate the same sulfate minerals found on Mount Sharp on Mars.

Although Basque lakes were teeming with brine shrimp during a research trip in June, Tutolo says the question for similar sulphate deposits on Mars is, “Is there a point where it gets so salty that nothing could live there?

The team has unique tools to aid their research, including an anaerobic chamber in Tutolo’s lab used to study chemical processes that occur completely in the absence of oxygen.

Mars is red because of all the iron on its surface. In addition, the planet’s atmosphere is far from the 20% oxygen present in the Earth’s atmosphere.

Thus, the anaerobic chamber allows the team to simulate conditions on Mars, conducting experiments in anoxic (oxygen-free) environments on iron-induced chemical reactions in the presence of water, Tutolo explains.

One of British Columbia's Basque Lakes

One of British Columbia’s Basque Lakes

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Understanding Mars’ geologic history can shed light on Earth’s evolution

Interpretation of the geological transition on Mars will help answer the question of whether the planet’s environment would still have been habitable had the climate become much drier and colder.

If there is potential for life to have evolved, could it exist on the surface of Mars at that time, and if so, what would that evidence look like in rocks?

Slight variations in the Earth’s motion — wobbling on its axis and expanding or contracting the distance of its orbit around the sun — have produced alternating ice ages and “warm houses,” or greenhouse climates, Tutolo notes. Mars’ motion through space changes a bit more drastically than Earth’s, so these cycles are reinforced on the Red Planet.

“There was probably a time when Mars was warming up and having water again, and going back and forth [from warmer to colder],” he says.

Learning more about the geologic history of early Mars can shed light on early Earth history, where geologic records from that time are not accessible, Tutolo says.

This is because the Earth’s crust is affected by plate tectonics whereby, over eons, the surface is subsumed into the planet’s mantle as continent-sized plates of rock collide. Thus, very little of the surface of the early Earth still exists.

“But on Mars, all of these rocks have been there since they were deposited, about 3.5 billion years ago or more,” Tutolo says. “So we can see these rocks on Mars and understand how life evolved on our planet from totally abiotic, or lifeless at all, to what it is today.”