Greenland’s giant crater is getting older

Tucked a kilometer below the surface of the Hiawatha Glacier in northwest Greenland, this impact crater has been challenging scientists since its discovery in 2015. Its 31 km diameter is enough to contain a city the size of Washington DC, probably the work of an asteroid one to two kilometers wide. But when did this monstrous collision occur? This is the puzzle that two independent teams from the University of Copenhagen in Denmark and the Natural History Museum in Stockholm in Sweden have solved.

Maps showing the location of the Hiawatha impact crater in northwest Greenland (left) and the shape of the Earth’s surface under the ice, showing the crater on the right. Credits: University of Copenhagen

Modern human influence?

Among the many speculations about the Hiawatha crater – the first to be discovered under the ice – is that it was formed only 13,000 years ago, when people had long settled the planet. The hypothesis shed light on the last ice age, which paleoclimatologists call the Dryas, a series of three periods of cooling that occurred between 16,500 and 11,700 years ago. Thus, the impact on the origin of Hiawatha Crater must have contributed to the last of these three periods, the Younger Dryas, which began 12,900 years ago and lasted 1,200 years. “Debris thrown into the atmosphere (water vapor, ash and dust) could affect the climate and melt a lot of ice. Thus, a sudden influx of cold water into the Nares Strait between Canada and Greenland could have occurred, which could have affected the sea currents of the entire region, causing the water and land to cool.explained in 2018 John Paden, a professor at the University of Kansas and co-author of a study reporting a surprising discovery in Scientific achievements.

View of the wall of the Hiawatha crater in Greenland. (Credit: Shfaqat Abbas Khan)

Difficult date

In reality, it turns out that the Hiawatha crater is much older: 58 million years old!

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