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Canada’s remote Gros Morne National Park is one of the few places where you can see the Earth’s mantle

An otherworldly landscapeDuring the warmer months, Canada’s easterly island of Newfoundland is a lush wonderland dotted with lakes, bogs and endless forests. But on Newfoundland’s west coast, wedged between the deeply carved fjords and towering peaks of Gros Morne National Park, a barren plateau emerges.

Known as The Tablelands, this vast desert-like landscape that resembles Mars is the result of half a billion years of geological activity. But beyond its striking appearance, the park was named a Unesco World Heritage site because it offers a scientific window into the past – and, potentially, into other worlds.

The Earth’s soul
The Tablelands is one of the few places on the planet where you can glimpse the “soul” of the Earth: its mantle, the deep layer of silicate rock found miles beneath the crust. This type of rock is rich in toxic metals and is inhospitable to most vegetation, which is why the Tablelands is so barren. In fact, compared with the rest of the lush Gros Morne National Park, the Tablelands sticks out like a sore thumb.

“What’s remarkable is not only [that it’s] so well exposed, it’s well preserved,” said Rob Hingston, visitor experience product development officer for Gros Morne National Park.

How did this happen?
According to Dr Alison Leitch, a geophysicist at Memorial University of Newfoundland, 500 million years ago, as the supercontinent of Pangea was beginning to form and the Iapetus Ocean was closing, what would now be considered North America and Europe were colliding. When continents shift, fragments of crust are often subducted, or recycled, back into the Earth, but in this case, a fragment of the Earth’s mantle, which had been a piece of the ocean floor, was pushed up to form the Tablelands. This landscape remained pretty well buried until finally, just 12,000 years ago after the last Ice Age, the mantle became visible.

“It would have eroded away in a few million years [but] it’s preserved because it’s been underground most of the time since it was formed,” said Leitch. “It just sort of popped up during post-glacial rebound like a lot of the other features that you see in western Newfoundland, and it’s being eroded away as we speak.”

Prior to the in-depty study of the Tablelands in the 1960s, plate tectonics were only a theory. When scientists realised that the barren rock emerging from the dense forest of Gros Morne was, in fact, a broken-off piece of the Earth’s mantle, it helped prove the theory that the Earth is covered in tectonic plates.

A “toxic” landscape
According to Dr Penny Morrill, a professor at Memorial University’s Earth Science Department, almost every continent has a piece of mantle but many are not as easily accessible. “Out of all the ones that I work at, the Tablelands is the only one that is like strikingly barren rock rising above the tree line,” she said. “It’s just so beautiful and it’s so accessible.”

Morrill has spent her career studying ophiolites (exposed pieces of mantle) around the globe, and now focuses on the Tablelands’ otherworldly landscape. According to Morrill, these rocks “have higher concentrations of metals that some plants would find toxic,” she said, explaining that most plants would wither away in this extreme environment. “One of the ways a plant survives in a place where there’s no nutrients… is that it’s a carnivorous plant, so it catches insects and gets its nutrients that way.”

One such plant can be found along the 4km Tablelands Trail: the pitcher plant, Newfoundland and Labrador’s provincial flower. This meat-eating purplish plant rears its head on long stem, demonstrating its tenacity as one of the few living things along the Tablelands.

Clues to Mars? Visiting the Tablelands may feel like a journey to another planet, but aside from its toxic minerals and alien landscape, scientists actually believe this remote corner of Earth can teach us something about life on Mars.

Part of Morrill’s research involves examining how life survives in the Tablelands, which may give us clues to how it could potentially exist on Mars. When Morrill was investigating groundwater that flows through the plateau, she was shocked to discover that it was full of microbial life.

According to Morrill, the cells living in the local groundwater here don’t feed on the nutrients we typically see supporting life, but rather on carbon monoxide and other “poisonous” elements. She believes this is the result of an underground process called “serpentinisation”. This occurs when water reacts with rocks from the Earth’s mantle, and it’s thought that the same process may have occurred on Mars. “Mars doesn’t have a very thick atmosphere, so any life on the surface would potentially be damaged by solar radiation,” she said. “So, if we’re looking for life on Mars, it may be protected in the subsurface … it’s a very protective environment on Mars where [life] could potentially exist.”

Spanning history
If you want to see some of the effects of these water-rock reactions, all you have to do is look. One of Morrill’s favourite things to do with visitors is to bring them to a place where new carbonate rock is always forming through precipitation. She’ll have them put one foot on the new precipitated rock and one foot on the original mantle “and then your two feet are spanning 500 million years of history”.

If you were to snap a photo of that, you’d have your own geological story to tell.

A potential game-changer
Beyond the many scientific contributions that have come from these mountains – from a better understanding of plate tectonics, to potentially uncovering how life could survive on Mars – the Tablelands may still hold a few more secrets.

“These rocks have the potential to sequester carbon dioxide,” said Morrill. A current study at Memorial University suggests that the Tablelands could potentially capture and store CO2. “That carbonate that you’re standing on when you’re at the site is because CO2 is coming out of the atmosphere, dissolving into the water and then precipitating as carbonate rock. That’s a long-term storage potential for carbon dioxide,” she said.

If we can discover additional ways to harness CO2 from the atmosphere, these rocks could be a game-changer in helping combat climate change.

It’s rare to find such a well-preserved, ancient piece of the geological past that reveals how the Earth moves and breathes and creates life. If you want to peer back 500 million years, western Newfoundland is the place to do it.

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