The Hiawatha impact
A 31-kilometre crater hides under a kilometre of Greenland ice — and turns out to be Paleocene, not recent.
- When
- Known to
- ± 540 thousand years
- Era
- Paleocene, Cenozoic
Radar surveys in 2015 revealed a large circular basin beneath the Hiawatha Glacier in northwest Greenland, and impact-shocked quartz in meltwater sediment confirmed it as a crater. Its age was initially unknown, and a young date would have made it a candidate for the Younger Dryas cooling. Argon and uranium-lead dating of impact-melted grains published in 2022 instead put it at about 58 million years ago, when the region was forested. It is a rare case of a hypothesis being killed cleanly by a date.