An immense, ancient impact crater has been discovered under the dense arctic ice covering Greenland. Over 300 metres deep and more than 30 kilometres wide, the crater is one of the 25 largest ever found on Earth. It’s also the first one to be found under a continental ice sheet.
The researchers behind the discovery say that the huge, bowl-shaped indentation was formed when an iron meteorite almost a kilometre wide smashed into the Earth as recently as 12,000 years ago. The impact zone in northwestern Greenland is now covered by the Hiawatha Glacier.
“The crater is exceptionally well-preserved, and that is surprising, because glacier ice is an incredibly efficient erosive agent that would have quickly removed traces of the impact. But that means the crater must be rather young from a geological perspective,” Professor Kurt H. Kjær, the leader of the team that worked on the discovery, said in a statement. "So far, it has not been possible to date the crater directly, but its condition strongly suggests that it formed after ice began to cover Greenland, so younger than 3 million years old and possibly as recently as 12,000 years ago – toward the end of the last ice age.”
In 2015, scientists first developed theories that there was a crater in the area. The team has since worked to survey the region using satellite imagery and radar systems capable of penetrating continental ice sheets.