Martian meteorites could provide clues about life on the planet

* Updated June 9, 2023

Kim Tait has loved rocks since she was a kid. 

She’d spot a rock, plop it in her pocket, and bring it home to investigate it using geology books.

Today, Tait is a mineralogist who has turned her lifelong fascination into a successful career. Tait, a senior curator of mineralogy at the Royal Ontario Museum, is studying 4.5-billion-year-old Martian meteorites that ejected off the surface of the planet, entered Earth’s atmosphere, and landed in Northwest Africa.

She’s using these meteorites to determine if the necessary ingredients for life—phosphorus and water—once existed on Mars. Tait’s research, funded through the Environmental Molecular Sciences Laboratory’s (EMSL) Fiscal Year 2022 Call for Large-Scale Research proposals, could also provide clues on how life has evolved on Earth. Tait is a featured guest on the EMSL podcast, Bonding Over Science, talking about her research. 

The history of Mars 

There is widespread evidence that water once flowed on the surface of Mars. However, water alone can’t indicate that life existed on the planet. Phosphorus is an essential component in DNA and RNA—the building blocks of life. Without phosphorus, life on Mars wouldn’t be able to evolve.  

Tait is looking at phosphates and sulfides, which are two mineral groups, to get a more accurate prediction of phosphorus and water availability for life on Mars, the origin of Martian water, and the evolution of the Martian atmosphere. By understanding Mars, this research could foreshadow what Earth may experience in the future. 

“We’re interested in understanding the history of Mars,” said Tait, who is also an associate professor in the Department of Earth Sciences at the University of Toronto. “We know that Mars had water flowing on it at some point.” 

Mars also was once a geologically active planet and has the largest volcano in the solar system, which is the size of Arizona. There has been no volcanic activity on Mars for the last 165 million years. 

“We don’t know how life formed,” Tait explained. “What was the first spark of life on our planet? Is there life out there? These are all sorts of fundamental questions answered by looking at geology.”

Using EMSL Instrumentation to Study Martian Meteorites 

Tait is examining processes for similarities between Mars and Earth to determine how pressure, temperature, and water or lack of water impacted Mars. For example, was there ever a time that Mars had bacteria or algae?  

“Maybe this will tell is a little bit about how life evolved on Earth,” Tait said. 

In order to determine if there was water availability on Mars, Tait is examining hydrous Martian phosphate minerals in melt inclusions.  

“I think we have 300 regions of interest that we could look at,” said Tait. “It’s a little bit like detective work.” 

In coordination with the Biogeochemical Transformations Integration Platform, Tait is using EMSL’s scanning transmission electron (SEM) microscope and atom probe tomography (APT) to conduct structural and chemical observations of the minerals. The SEM determines the crystal structure and how the atoms are arranged. When the sample is transferred from the SEM to the APT, a pulse laser strips the sample atom by atom. The tips of the APT instrumentation are less than the depth of human hair, but finitely identify atoms. The sample travels through the mass spectrometry instrument, lands on a detector, and the atom is identified. Then a 3D reconstruction of the atom is built. 

“It’s a really powerful instrument,” says Tait of the APT.

Tait is using EMSL’s nano Secondary Ion Mass Spectrometry (NanoSIMS) to determine atmospheric processes on Mars. Using sulfur isotopes as tracers, NanoSIMS allows researchers to look at the elements and isotopic ratios and to identify sulfur. 

EMSL expertise raises bar for user science 

In addition to access to EMSL instrumentation, Tait works alongside the instrument owners and experts to learn how to use the resources and to evaluate new research approaches.  

“I’ve used APT all over the world but having instrumentation and people all together really changes things,” she added. 

EMSL material scientist Daniel Perea and Sandra Taylor, a chemist with Pacific Northwest National Laboratory, taught Tait the tricks of the trade when it comes to collecting data and 3D animations. Taylor even recorded a tutorial that Tait can take back to her own institution and use to continue data processing. 

“Having those intellectual conversations before starting to collect data is so valuable,” said Tait. “That collaborative think tank is what is so unique about EMSL. It’s like having a sous chef and a pastry chef—or a Michelin chef because they are world renowned scientists on their own.”