Could the history of Mars be set in stone? Meteorite discovery may offer clues to Red Planet's past

Hiding inside a piece of an ancient meteorite that is at least 4.4 billion years old lies potential secrets to the history of Mars.

The meteorite, known as NWA 8171, contains a mineral that has not been discovered in Martian material before. And it might offer clues about how the planet was formed.

"The most exciting part is that we potentially have a new rock type on Mars,” said Tanya Kizovski, an assistant professor at Brock University's earth sciences department who made the discovery.

"We are expanding our knowledge in terms of what is possible geologically.”

NWA 8171 was first discovered in 2013 and is one of at least 18 pieces that came through the atmosphere in one rock and then exploded. The fragments fell to the Earth and were picked up one by one and eventually identified as originating from the same meteorite.

It is currently being held in the Royal Ontario Museum’s collection in Toronto, where Kizovski was able to examine it.

It is a breccia — a sedimentary rock made up of broken bits of other rocks — that contains insights into Mars’ geological history. She called it “the perfect place to start” because it’s so old and contains so many rock types.

Inside the breccia, Kizovski found garnet.

Red-coloured garnet gems are often used in jewelry, and is January’s birth stone, but what she found is more specifically referred to as andradite and can be many colours. Kizovski said the garnet found in NWA 8171 is "definitely dark-coloured," but it's hard to say whether it's green or yellow.

Chris Herd, who did his PhD on Martian meteorites, called the breccia “probably one of the most significant discoveries in Martian meteorite research in the last 15 years.”

He says it can provide insight into the planet’s different geological processes.

“Garnet is not something that we typically see or have seen. We certainly have not seen it in Martian meteorites before,” said Herd, a professor at the University of Alberta.

“It challenges us to think of the processes, the conditions that existed on Mars or within Mars, that could give rise to this tiny little piece of rock like this.”

Herd says there’s a possibility of finding more garnet in the other fragments, which could help researchers better understand the significance of the discovery.

While Kizovski has found garnet in a Martian meteorite for the first time, she cautions that it’s unclear where the mineral came from.

“There's been many, many meteorites that have hit Mars over its history,” she said. “So technically this could be a survived piece of one of those meteorites that hit Mars.”

To confirm whether the mineral is of Martian origin, researchers would have to destroy a portion of the sample to verify its isotopic signature to see if it matches Mars. An isotopic signature is the atomic makeup of any material, which scientists use to trace the geographic origin or history of that material.

So, the plan is to study it as much as possible first.

While there is still uncertainty, Kizovski says it still helps provide valuable information on the planet — another piece in the puzzle of understanding Mars’ geologic history and climate.

For Mars, little is known about whether it has plate tectonics — the science that, for Earth, helps explain the gradual formation of the continents over billions of years — but Kizovski says this discovery might open the door to learning more.

“What excites me the most is the possibility of now hopefully looking back into some of the data we have from rovers and orbiters and maybe finding evidence of this rock type in places we didn't look before,” Kizovski said.

“There's lots of really cool avenues to go down here and I'm excited to keep exploring.”