Topography of the newly discovered Greenland crater. Image: NASA Goddard Space Flight Center
NASA has detected a massive, ancient crater buried under two kilometers of ice in northwest Greenland. Even more surprising, it is the second crater discovered under the thick ice of the region in recent months.
According to a study published on Monday at 36.5 kilometers (22 miles), the crater was formed by an asteroid impact in the last 2.6 million years. Geophysical research letters. If it is confirmed that the feature is the consequence of an asteroid attack, it will be classified as the 22th largest impact crater on Earth.
Scientists have identified about 200 impact craters on our planet, but this is only the second time in history that a crater has been detected beneath a layer of ice. In November, NASA announced that it had seen the first subglacial impact crater buried under the Greenland Hiawatha Glacier, located only 183 kilometers from the new site.
Inspired by that discovery, a team led by NASA glaciologist Joseph MacGregor began scanning Greenland for other craters. The new crater appears to be larger and older than the Hiawatha impact site.
Both features were detected using satellite images and aerial images captured by NASA's Operation IceBridge fleet.
Given their proximity to each other, MacGregor and his colleagues reflected on whether these craters could have been formed by the same impact event. Perhaps a binary asteroid system hit the Earth, or an asteroid broke into two pieces during entry into the atmosphere.
But observations of the topography of the new crater reveal that it is much more eroded than the Hiawatha crater, suggesting that they could not have formed at the same time.
"The morphology of the second structure is less deep. [and] "The ice that covers it is agreeable and older," write in the MacGregor study and its co-authors. "We came to the conclusion that the identified structure is very likely to be an impact crater, but it is unlikely to be a twin of the Hiawatha impact crater."
Read more: Scientists discover a hidden asteroid crater under a mile of Greenland ice
The Hiawatha crater was probably formed in the last 100,000 years. More research will be required to restrict the age of the second crater, but it is likely to have been created within the Pleistocene period, which began 2,588,000 years ago. According to the estimated age of its ice sheet cover, 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 the Paterson crater. This name would honor the late glaciologist Stan Paterson, who helped reconstruct climate data for the past 100,000 years using Greenland ice cores.
"The possibility of additional subglacial craters beneath the ice sheets of Greenland and Antarctica should be investigated, as our discovery further emphasizes the ability of ice sheets to bury and preserve evidence of land impacts," the team said.
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