Saturday , January 16 2021

NASA discovers other crater hidden under Greenland ice



Topography of recently discovered Greenland's crater. Image: NASA Goddard Space Flight Center

NASA has discovered a massive, old crater buried under two kilometers of ice in northwest Greenland. Surprisingly, the second crater has been discovered during the thick ice of the region in recent months.

Stretching over 36.5 kilometers (22 miles), the crater was probably formed by an asteroid effect over the past 2.6 million years, according to a study published Monday in Geophysical research letters. If the function is confirmed to have fallen out of an asteroid strike, it will rank as the 22nd largest battleground known on Earth.

Scientists have identified about 200 battlegrounds on our planet, but it is only the second time in history that a crater has been recorded under an ice sheet. In November, NASA announced it had seen the first underglacial battleground buried under Greenland's Hiawatha glacier, just 183 kilometers away from the new site.

Inspired by this discovery, a team led by the NASA Glacier Joseph MacGregor began scanning Greenland for other craters. The new crater seems to be larger and older than the Hiawatha impact site.

Both features were spotted using satellite images and aerial photography captured by NASA's Operation IceBridge aircraft fleet.

Because of their proximity to each other, MacGregor and his colleagues considered whether these craters might have been formed by the same impact event. Maybe a binary asteroid system hit the ground, or an asteroid broke into two pieces under atmospheric entrance.

But observations of the new crater's topography reveal that it is far more eroded than the Hiawatha crater, suggesting that they could not have formed at the same time.

"The morphology of the other structure is lower [and] its overlying ice is conformable and older, "writes MacGregor and his co-authors in the study." We conclude that the identified structure is very likely a hit crater, but it is unlikely to be a twin of the Hiawatha battleground. "

Read more: Scientists discover hidden asteroid crater under a mile of Greenlandic ice

The Hiawatha crater probably formed within the last 100,000 years. It will take more research to limit the age of the second crater, but the odds are that created during the Pleistocene period, which began 2,588,000 years ago. Based on the estimated age of its ice cap, it was formed at least 79,000 years ago, the team said.

The structure does not yet have an official name, but the authors recommended calling it Paterson Crater. This name would honor the late glaciologist Stan Paterson, who helped reconstruct climate data in the last 100,000 years of Greenland ice cores.

"The possibility of further underglacial craters under the Greenlandic and Antarctic ice sheets should be explored, as our discovery further underlines the impact of burying and preserving evidence of terrestrial effects," said the team.

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