Rare black iceberg spotted off Labrador coast could be 100,000 years old, prof says

CBC

04-06-2025

A rare black iceberg spotted off the coast of Labrador is making a splash on social media after a fish harvester living in Carbonear, N.L., took a photo of it while fishing for shrimp last month.
Originally from the Faroe Islands, Hallur Antoniussen was working with a crew on board the Saputi factory freezer trawler off the coast of Labrador in mid-May.
He'd never seen an iceberg like this one before.
"I have seen icebergs that are rolled, what they say have rolled in the beach with some rocks in it. This one here is completely different. It's not only that he is all black. He is almost ... in a diamond shape," Antoniussen said in an interview with CBC Radio's Labrador Morning.
He spotted the berg after going up the ship's crane when they were more than 100 kilometres offshore in the Hopedale channel, located between Nain and Hopedale.
A crew member had counted 47 icebergs in the area just the day before.
Antoniussen doesn't think it's a berg that tipped over — or rolled on the beach — picking up dirt and rocks after getting grounded. He's seen a lot of icebergs over his 50 years of fishing off of Greenland, and more recently off the Labrador coast since 1989.
The 64-year-old said it was hard to estimate the size of the iceberg at sea but figured it was at least three times the size of a regular bungalow.
He took a picture from roughly six kilometres away.
"It's something you don't see very often, and a camera is not something I run around [with] when I'm working. So, I just ran to my room and took my phone and snapped this picture," he said.
Antoniussen said the berg looked like a rock with lots of really dark greys and black veins in it, and quickly ruled out that a shadow was being cast on it.
He took the photo to show other crew members on the fishing boat. Then Antoniussen posted it on Facebook, and it soon took off, garnering hundreds of comments after being shared around.
Commenters have mused about everything from aliens to precious metals, and even dinosaurs being hidden in the ice.
"It's an Oil Berg," said one poster.
"Looks like a giant [woolly] mammoth!" exclaimed another.
Antoniessen is clear: this is a real photo.
Other people wondered if the iceberg has volcanic ash in it, a result of some ancient eruption.
An impressive iceberg
Lev Tarasov, a Memorial University professor of physical oceanography, doesn't rule that last theory out completely.
Tarasov says there are volcanoes beneath the ice caps of Iceland, and while he's not exactly sure about volcanoes in Greenland, he added that scientists have measured hotspots in the landmass's central region.
Like Antoniussen, he hasn't seen an iceberg quite like this one before.
Tarasov observed smaller versions of the black iceberg during his fieldwork on the Kangerlussuaq Fjord in Greenland last summer -— just not as impressive, he said.
He guesses it could be between 1,000 and 2,000 years old, but could also contain ice that's older than 100,000 years old.
Tarasov said ice from all over Greenland is slowly converging toward its coastline, and when it gets there, it breaks off to form icebergs.
Those icebergs can take one to three years before reaching the Newfoundland and Labrador coastline.
A terrestrial journey
Tarasov says it's a reminder just how dynamic ice can be.
Ice streams, also known as outlet glaciers, move much faster than other parts of the ice sheet; they carry ice from the interior, traveling through deep valleys or channels out to the coast.
They pick up rocks and dirt along the way.
"There's parts of the ice that are actually flowing up to 20 kilometres per year, which would mean that ... the ice is moving maybe a few metres every hour," Tarasov said.
The bottom of the ice grinds against the earth's crust, he explained. There's a whole lot of churning, turning all that rock and sediment into a powder that then spreads up through columns of ice.
It would take a long time for that ground-up rock to spread so uniformly throughout the ice, Tarasov said.
Tip of the iceberg
Tarasov theorizes that the black berg was probably part of a much larger chunk of ice before it broke off into the water.
"Over time, as it travels around Baffin Bay and down the coast of Labrador, it's melting away. So I think a lot of that ice is melted away. Maybe the part that's clean is underneath, right? Again, 90 per cent of the ice is underneath the water. So we're only seeing the tip of the iceberg on top," he said.
Tarasov thinks the iceberg rolled over at some point, and is now showing its underbelly.
He also offers another possible explanation for the iceberg's intriguing colour.
There is strong evidence showing that an asteroid struck the northwest corner of Greenland some 12,000 years ago, he said. The iceberg could have some dust from that meteorite strike if it came from the area.
No matter what, the ice likely isn't new: it's quite possible the dirt on the iceberg may not have seen the "light of day for hundreds of thousands of years," Tarasov said.