Sunday , August 1 2021

Crater found under Greenland's ice among the 25 largest impact craters on Earth



An international team led by Researchers from the Center for GeoGenetics at the Natural History Museum of Denmark, University of Copenhagen, discovered a 31-kilometre the wide meteorite impact crater buried beneath the ice sheet in Greenland's Hiawatha Glacier.

If confirmed, it would be the first impact crater discovered under one of Earth's continental ice sheets, said researcher from the University of Copenhagen in Denmark.

Signs of the crater were first detected by NASA's Operation Icebridge, an airborne mission that uses radar to track changes in ice on Greenland's ice sheet.

The researchers have been working for the last three years to verify their discovery, initially made in 2015.

All about the crater

According to the study published in the journal 'Science Advances,' the crater measures are more than 31 km in diameter, A special and bigger area than Paris and larger than Washington DC, which places it among the 25 largest impact craters on Earth.

What are impact craters?

An impact crater is a circular depression on a surface referring to a planet, moon, asteroids, or other celestial bodies, caused by a collision of a smaller body (meteor) with the surface.

How did such a big crater form?

Map of the bedrock topography of the ice sheet and ice-free land surrounding the Hiawatha impact crater. The structure is 31 km (Image: Natural History Museum of Denmark)

The crater is formed when a kilometre-wide iron meteorite smashed into northern Greenland but has been hidden under nearly a kilometer of ice.

"The crater is exceptionally well-preserved, and that is surprising because glacier ice is an incredibly efficient erosive agent "That would quickly removed traces of the impact," said Professor Kurt H Kjaer from the Natural History Museum of Denmark.

"So far, it has not been possible to form it after ice began to cover Greenland, so it was more than three million years old and as recently as 12,000 years ago – toward the end of the last ice age, "he said.

When was it first discovered?

Close-up of the northwestern ice-sheet margin in Inglefield Land. The Hiawatha impact crater was discovered beneath the semi-circular ice margins (Image: Natural History Museum of Denmark)

The crater was first discovered in July 2015 as the researchers inspected a new map of the topography beneath Greenland's ice-sheet.

"Previous measurements of Hiawatha Glacier radar were part of a long-term NASA effort to map Greenland's changing ice cover," Joe MacGregor, a glaciologist with NASA, explains.

"What we really needed to test was a dedicated radar survey there. The details of a circular circular rim, central uplift, disturbed and undisturbed ice layering, and basal debris – it's all there. "

They noticed a huge, but undetected circular depression under Hiawatha Glacier, sitting at the very edge of the ice sheet in northern Greenland.

"We immediately knew this was a special time it became clear that it would be difficult to confirm the origin of the depression," said Kjaer.

The 20-tonne iron meteorite sits in the courtyard at the Geological Museum in Copenhagen.

Also read | This new Artificial Intelligence technique just found 6,000 new craters on Moon

Also read | Top seven impactful largest craters unearthed in the past few years

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