HomeInternationalMassive meteor crater discovered beneath Greenland's ice much older than thought

Massive meteor crater discovered beneath Greenland’s ice much older than thought

The Hiawatha crater was exceptionally nicely preserved regardless of glacier ice being extremely efficient at erosion. Its state fueled speak that the meteorite may need hit as not too long ago as 13,000 years in the past.

However, the crater, which is without doubt one of the world’s largest, has now been definitively dated — and it’s much, much older. In reality, it slammed into the Earth only a few million years after dinosaurs went extinct, about 58 million years in the past.

“Dating the crater has been a particularly tough nut to crack, so it’s very satisfying that two laboratories in Denmark and Sweden, using different dating methods arrived at the same conclusion. As such, I’m convinced that we’ve determined the crater’s actual age, which is much older than many people once thought,” mentioned Michael Storey, head of geology on the Natural History Museum of Denmark, in a information launch.

When the asteroid hit, the Arctic was coated in balmy rainforest with temperatures of round 68 levels Fahrenheit (20 levels Celsius). Local inhabitants would have included crocodiles, turtles and primitive hippo-like animals, mentioned Storey, who was an writer of a brand new paper on the crater printed within the journal Science Advances.

The Hiawatha impression crater might swallow up Washington DC and is bigger than about 90% of the roughly 200 beforehand identified impression craters on Earth.

The researchers collected sand and rock samples in Greeland to determine when the meteor hit.

It’s not but identified whether or not the meteor that struck Greenland disrupted the worldwide local weather in the identical approach the 200-kilometer huge asteroid that created the Chicxulub crater in Mexico — that doomed the dinosaurs — did some 8 million years earlier. But the Greenland meteorite would have devastated plant and animal life within the speedy area.

To date the glacier, researchers collected sand and rocks from rivers flowing from the glacier. Those samples would have been heated by the meteor impression. They had been dated utilizing strategies that detect the pure decay of long-lived pure radioisotopes contained within the rock.

Crystals of the mineral zircon contained within the rock had been dated utilizing uranium-lead courting. The uranium isotopes begin decaying as zircon crystallizes, reworking into lead isotopes at a gradual and predictable charge. The approach pointed to a date of about 58 million years in the past.

The grains of sand had been heated with a laser, and the researchers measured the discharge of argon gasoline, which is produced from the decay of the uncommon however naturally occurring radioactive isotope of potassium, often called Okay-40.

“The half-life of K-40 is exceptionally long (1,250 million years) which makes it ideal for dating deep-time geological events like the age of the Hiawatha asteroid,” Storey mentioned.

The approach urged an analogous time-frame for the meteor strike.

“It is fantastic to now know its age. We’ve been working hard to find a way to date the crater since we discovered it seven years ago,” mentioned coauthor Nicolaj Krog Larsen, a professor on the GLOBE Institute on the University of Copenhagen, who first discovered the crater.



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