An international research team including ETH Zurich has dated the huge Hiawatha impact crater, which is located under a layer of ice almost a kilometer deep in Greenland. The crater is therefore 58 million years old – much older than was initially speculated. The iron meteorite that once hit the earth in north-west Greenland with enormous energy was more than one kilometer in size.
Researchers first announced the discovery of the crater in 2018. Although it was not yet possible to date the crater at the time, they speculated that the impact event could have taken place around 12,000 years ago. According to this assumption, the meteorite impact could have heralded the Younger Dryas – a sharp cold snap in the history of the earth at the end of the last glacial period. But that was obviously not the case.
Rather, the meteorite crashed into Greenland 58 million years ago. The research team, led by the Natural History Museums of Sweden and Denmark and the University of Copenhagen, reports this in the journal Science Advances. Consequently, the impact is not related to Pleistocene glaciation.
For the study, the researchers age-dated grains of sand and zirconium crystals that they collected downstream of the Hiawatha Glacier. “Dating the crater was a particularly tough nut to crack,” said co-author Michael Storey of the Natural History Museum of Denmark, according to a statement from the University of Copenhagen.
But now that the age of the crater has been determined, the potential impact of the impact on the climate during an important period in Earth’s history can be examined, added lead author Gavin Kenny of the Swedish Natural History Museum. Large meteorite impacts can have a lasting and global impact on the climate. However, there is currently no evidence for the Hiawatha impact.
The Greenland impact crater has a diameter of 31 kilometers and is one of the 25 largest on earth. The whole city of Paris would fit into it. However, it falls far short of the Chicxulub crater in what is now the Gulf of Mexico. The meteorite, which most likely sealed the end of the dinosaurs around 66 million years ago, left a crater around 200 kilometers in diameter.