Massive Crater Discovered Under Greenland Ice
When one thinks of a massive asteroid colliding with Earth, the extinction of the dinosaurs 65 million years ago likely comes to mind.
The prevailing theory is the Chicxulub crater, 115 miles wide and located in the Yucatán Peninsula in Mexico, was the landing ground for a deadly asteroid that crashed into the world tens of millions of years ago and set into motion a chain of events that killed off the dinosaurs, ScienceDaily noted.
Now, a study published in the journal Scientific Advances details the discovery of another asteroid crater that likely hit in the relatively recent history of Earth, although this one is not quite as big as the catastrophic crater found in Mexico. And its true effect is still unknown.
This new crater was found underneath the ice shelf of the Hiawatha Glacier in Greenland, the study says. At 19 miles wide, it’s bigger than Paris or Washington, D.C. — and likely hit sometime in the recent history of Earth judging by how well preserved it is, the study says.
“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,” study author Kurt H. Kjær said in a press release from The University of Copenhagen.
The discovery was made possible thanks to NASA’s Operation IceBridge, a initiative to scan “changes in polar ice” and make that information public for others to review in maps, according to NASA. Researchers at the University of Copenhagen’s Centre for GeoGenetics at the Natural History Museum of Denmark helped examined the data from NASA, discovering the shape of what appeared to be a huge crater hidden underneath ice in Greenland in July 2015.
NASA glaciologist Joseph MacGregor worked with the researchers after their initial discovery, looking at “radar measurements” of the possible crater that were taken by a research plane from the Alfred Wegener Institute in Germany, the press release says.
And what did they find?
“A distinctly circular rim, central uplift, disturbed and undisturbed ice layering, and basal debris,” MacGregor said in the press release.
In other words, the evidence that it is indeed a crater caused by an asteroid collision is “all there,” MacGregor said.
Researchers also found a channel where some of the melted water in the glacier was freely flowing — and used that to collect different rocks to look for more evidence of a high-impact collision.
They found shocked quartz and glass, which forms after a big collision, as noted by Gizmodo. National Geographic reported that it’s estimated that the asteroid would have been about three-quarters of a mile wide with a whopping weight of up to 12 billion tons.
There is also a 20-ton meteorite located at the Geological Museum in Copenhagen — not far from the crater — which led researchers to theorize if the two were connected, the study noted.
Kjær told National Geographic that while it is not included in the paper, his findings could eventually help support the Younger Dryas impact hypothesis, which says huge animals like mammoths died during the Ice Age because of fires caused by a big impact.
But there’s still a long ways to go before that argument can be supported, Kjær cautioned the magazine.
“This may generate a lot of discussion, and we need to find out,” he said, according to National Geographic. “We won’t know until we have a proper date.”
Nicolaj K. Larsen, a co-author of the study, told Gizmodo that researchers are already trying to figure out how to get a more specific date of impact.
“We are currently trying to come up with ideas on how to date the impact,” she told the outlet. “One idea is to drill through the ice and get bedrock samples that can be used for numerical dating.”