Hiawatha crater in Greenland is older than previously thought

(ORDO NEWS) — Danish and Swedish researchers have dated the huge Hiawatha impact crater, a 31km-wide asteroid crater buried under a kilometer-long layer of Greenland ice.

The dating put an end to speculation that the asteroid hit after humans appeared and opens up new insights into the evolution of the Earth in the post-dinosaur era.

Since 2015, when researchers at the University of Copenhagen’s GLOBE Institute discovered the Hiawatha impact crater in northwest Greenland, uncertainty about the crater’s age has been the subject of much speculation.

Could an asteroid have crashed into the Earth 13,000 years ago, when people have long inhabited the planet? Could its collision have been the catalyst for the nearly 1,000-year period of global cooling known as the Younger Dryad?

New analyzes of grains of sand and rocks from the Hiawatha crater by the Natural History Museum of Denmark and the GLOBE Institute at the University of Copenhagen and the Swedish Museum of Natural History in Stockholm show the answer is no.

The Hiawatha impact crater is much older. It is 58 million years old, according to a new study published today in the journal Science Advances.

“The dating of the crater has been a particularly difficult nut to crack, so it’s very pleasing that two laboratories in Denmark and Sweden, using different dating methods, came to the same conclusion.

Thus, I’m convinced that we have determined the real age of the crater, which is much older, than many thought before,” says Michael Storey of the Natural History Museum of Denmark.

Hiawatha crater in Greenland is older than previously thought 2

“Determining the new age of the crater surprised us all. In the future, this will help us study the possible impact on climate at an important era in the history of the Earth,” says Dr. Gavin Kenny from the Swedish Museum of Natural History.

Professor Nikolaj Krogh Larsen of the GLOBE Institute at the University of Copenhagen, one of the people who helped discover the Hiawat impact crater in 2015, is pleased that the exact age of the crater has now been confirmed.

“It’s fantastic that we now know its age. We’ve been hard at work finding a way to date the crater since we discovered it seven years ago. Since then, we’ve traveled to the area several times to collect samples related to the Hiawatha impact,” says Professor Larsen.

Age detected with laser beams and grains of sand

When the asteroid Hiawatha crashed into the Earth’s surface, there was no kilometer-thick ice sheet, releasing several million times more energy than an atomic bomb.

At the time, the Arctic was covered in temperate rainforest and wildlife abounded – and temperatures of 20 degrees Celsius were the norm. Eight million years earlier, an even larger asteroid crashed into present-day Mexico, causing the extinction of Earth’s dinosaurs.

The asteroid crashed into the Earth, leaving behind a crater thirty-one kilometers wide and one kilometer deep. The crater is large enough to contain the entire city of Washington.

Today, the crater lies beneath the Hiawatha Glacier in northwest Greenland. The rivers flowing from the glacier provided the researchers with sand and rocks that were superheated by an impact 58 million years ago.

Sand was analyzed at the Natural History Museum of Denmark by heating grains with a laser to release argon gas, and rock samples were analyzed at the Swedish Museum of Natural History using uranium-lead dating of the mineral zircon.

Clear evidence that Hiawatha’s impact disrupted the global climate is still lacking. However, the dating of the crater allows the international research team working on the crater to begin testing various hypotheses to better understand the impact it has had on local and global climate.

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