Beneath the frozen wastes of the Arctic, a three-way geopolitical tug-of-war is taking place over which country owns a ridge of undersea mountains.

6th July, 2022.      //   General Interest  // 

Arctic sea ice (Credit: Getty Images)

One of the most mysterious mountain ranges in the world is not visible on any ordinary map. You can’t see it on the most popularly used flat map of the world, the Mercator projection, or on the Peters projection that is a popular (and more accurate) alternative. On a spinning globe, the plastic axle at the North Pole often covers it up, as if there’s nothing to see.

But this is where you can find the Lomonosov Ridge, a vast mountain range running from the continental shelf of Siberia towards Greenland and Canada. The mountain range stretches for more than 1,700km (1,060 miles), its highest peak is 3.4km (2.1 miles) above the ocean floor.

This little-known mountain range is at the centre of three nations seeking sovereignty over the seabed around the North Pole. According to Denmark, the mountain range is an extension of its autonomous territory of Greenland. According to Russia, it is an extension of the Siberian archipelago Franz Josef Land. And according to Canada, it is an extension of Ellesmere Island in the Canadian territory of Nunavut.

So who is right?

The ridge was first discovered in 1948 by researchers on one of the Soviet Union’s early expeditions to the central Arctic. From a camp on the sea ice, the Soviet scientists detected unexpectedly shallow waters to the north of the New Siberian Islands. It was the first hint that the ocean was split into two basins by the ridge, rather than being one large, featureless basin, as previously assumed. In 1954, the researchers published a map showing an underwater mountain range, which they named after the 18th-Century poet and naturalist Mikhail Lomonosov, who had predicted 200 years before that such features would be found in the Arctic basin.

Today, more than 70 years after the ridge was detected, it remains an enigmatic feature in one of the most poorly mapped seafloors in the world. Even with modern ships passing powerful 864-beam arrays of sonar down through the Arctic waters, the resolution of the ridge is only in the order of hundreds of metres. That’s like being just about able to distinguish one end of an athletics track from the other side.

In such a poorly charted area, new mapping expeditions always lead to surprises. “It’s like putting on a new pair of glasses every time,” says Paola Travaglini, who has led mapping of Arctic the seafloor on expeditions aboard Canada’s CCGS Louis S St Laurent icebreaker. “You never know what you’re going to find.”

But mapping the peaks and valleys of this mountain range alone isn’t enough to determine how it formed, which landmasses it is a part of, and which nations can credibly claim it. To do that, scientists need to physically get hold of a piece of the ridge – a lump of rock that might be able to reveal a geological trace of the mountain range’s origins.

Hard evidence

Christian Knudsen, a geologist at the Geological Survey of Denmark and Greenland (GEUS), was involved in analysing a chunk of the ridge. Scientists from Denmark, Canada and Russia have dredged rocks from around the mountain range, but the difficulty is always proving that what they’ve picked up is really a part of the ridge, rather than just some pebbles or boulders lying around that could have come from anywhere. Ice sheets formed on Arctic coastlines have a tendency to sprinkle detritus all around the seafloor as they drift, leaving a trail of “drop stones”. A drop stone that hitched a ride on an iceberg from Siberia or northern Canada could easily be scooped up from the ridge by accident, giving a false result.

But it is hard to take a piece out of a mountain range that is submerged beneath hundreds of metres to several kilometres of water, topped with floating sea ice. It’s hard enough to get there in the first place. A team of researchers from GEUS, led by Christian Marcussen, managed to dredge the sample from on board the Oden, Sweden’s research icebreaker, in 2012.

Marcussen’s scientists were able to dredge the ridge at a depth of 3km (1.87 miles). Among the rocks they drew back to the surface was an orange-coloured lump around the size of a rugby ball. This was the material that Knudsen later analysed. “In the beginning no one paid attention to this rust-orange-brown crust, but I was curious to see what it was,” says Knudsen. “So we cut it.”

Inside he found something unexpected: layer upon layer of fine lines, much like tree rings. This layered crust was rich in manganese oxide, which forms in nodules on the seafloor where there is very little sediment. The nodules take many thousands of years to form, so it was a hint that the rock that had formed in-situ at the ridge, and was not a drop stone. Knudsen measured the age of the rock using beryllium isotopes – Beryllium-10 is a radioactive isotope that forms in the stratosphere, and over time decays to Beryllium-9. By measuring the ratio of the two, Knudsen could get the age of the rock.

What he found was a steady eight-million-year timeline of the rock’s history through the many layers of the crust, with the oldest rock next to a base layer of sandstone at the bottom, and the outer layer very recent.

“It proved that this rock has been sitting in this position for eight million years in the polar basin – since before the Ice Age,” says Knudsen. It felt, he says, like he was Sherlock Holmes finding a footprint outside the window. “I could prove that this rock was actually from the Lomonosov Ridge.”

But it was sandstone below the rust-orange crust that had the most interesting information about the mountain range. The lines formed in this rock were folded, a signature mark of sandstone that has been crumpled in a mountain-building event. The clays were turned into micas as the mountain was made, beginning another isotope “clock” as it did so – this time relying on an isotope of potassium – which helped Knudsen to date the age of the mica, and therefore of the mountains themselves. It turned out the mountain-folding event was 470 million years ago. The sand grains that made up the rock, though, were much older – closer to 1.6 billion years.

Why mountains matter

As coastal nations, Russia, Denmark and Canada of course already have sovereign rights over the seafloor close to their own shores. Coastal countries can establish an Exclusive Economic Zone that stretches up to 200 nautical miles (370km) from shore, which gives them rights to activities like fishing, building infrastructure and extracting natural resources, under the UN Convention on the Law of the Sea. That law also permits a country to extend its rights over the seabed further – if there are seafloor features that they can prove are an extension of their continental shelves.

For such a seafloor feature to count in a country’s favour, there has to be evidence that it is a piece of submerged land – and not an oceanic ridge that has always been underwater and has little to do with the country’s land mass.

What Knudsen’s findings boil down to is evidence that the Lomonosov Ridge is indeed submerged land, and not formed from seafloor spreading, like the mid-Atlantic ridge that runs like a seam from Iceland down towards Antarctica. The same finding is backed up by other studies, including seismic research into the structure of the crust, led by Ruth Jackson of the Geological Survey of Canada, and other crucial evidence, such as extensive research to map the seafloor in the area.

“It’s definitely continent,” says Knudsen. “And it’s continent that is similar to what we find in eastern Greenland – it is a continuation of Greenland, that’s our main point. We have taken the rocks, proved they actually came from the ridge, and we understand what they are. And then we are home,” says Knudsen.

The thing is, while the ridge may well be an extension of Greenland, if you look at it from the other end it is also an extension of Russia. Rocks of a very similar sort have been found on the Russian archipelago of Franz Josef Land, to the north of Novaya Zemlya, Knudsen notes. And Canada, too, has evidence that the Lomonosov Ridge is a prolongation extending from Ellesmere Island, perhaps not surprising given that Ellesmere nestles close to Greenland via a narrow strait just 20km (12.5 miles) wide at the northern end.

In fact, it’s perfectly possible that the Lomonosov Ridge is Russian, Canadian and Greenlandic all at once.

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