Giant impact crater in Greenland occurred a few million years after dinosaurs went extinct

Credit: Uwe Dedering @ Wikipedia

Another crater controversy ends as two different dating methods produced the same result.
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Danish and Swedish researchers have dated the enormous Hiawatha impact crater, a 31 km-wide asteroid crater buried under a kilometer of Greenlandic ice, says the University of Copenhagen.

The dating ends speculation that the asteroid impacted after the appearance of humans and opens up a new understanding of Earth’s evolution in the post-dinosaur era.

Ever since 2015, when researchers at the University of Copenhagen’s GLOBE Institute discovered the Hiawatha impact crater in northwestern Greenland, uncertainty about the crater’s age has been the subject of considerable speculation.

Could the asteroid have slammed into Earth as recently as 13,000 years ago, when humans had long populated the planet? Could its impact have catalyzed a nearly 1,000-year period of global cooling known as the Younger Dryas?

New analyses performed on grains of sand and rocks from the Hiawatha impact crater by the Natural History Museum of Denmark and the GLOBE Institute at the University of Copenhagen, as well as the Swedish Museum of Natural History in Stockholm, demonstrate that the answer is no.

The Hiawatha impact crater is far older. In fact, a new study published in the journal Science Advances today reports its age to be 58 million years old.

“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,” says Michael Storey of the Natural History Museum of Denmark.

“Determining the new age of the crater surprised us all. In the future, it will help us investigate the impact’s possible effect on climate during an important epoch of Earth’s history” says Dr. Gavin Kenny of the Swedish Museum of Natural History.

As one of those who helped discover the Hiawatha impact crater in 2015, Professor Nicolaj Krog Larsen of the GLOBE Institute at the University of Copenhagen is pleased that the crater’s exact age is now confirmed.

“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. Since then, we have been on several field trips to the area to collect samples associated with the Hiawatha impact,” says Professor Larsen.

Full article here.