Several years after scientists discovered what was considered the oldest crater a meteorite made on the planet, another team found it’s actually the result of normal geological processes.
During fieldwork at the Archean Maniitsoq structure in Greenland, an international team of scientists led by the University of Waterloo’s Chris Yakymchuk found the features of this region are inconsistent with an impact crater. In 2012, a different team identified it as the remnant of a three-billion-year-old meteorite crater.
“Zircon crystals in the rock are like little time capsules,” said Yakymchuk, a professor in Waterloo’s Department of Earth and Environmental Sciences. “They preserve ancient damage caused by shockwaves you get from a meteorite impact. We found no such damage in them.”
Additionally, there are multiple places where the rocks melted and recrystallized deep in the Earth. This process—called metamorphism—would occur almost instantaneously if produced from an impact. The Waterloo-led team found it happened 40 million years later than the earlier group proposed.
“We went there to explore the area for potential mineral exploration, and it was through close examination of the area and data collected since 2012 that we concluded the features are inconsistent with a meteorite impact,” Yakymchuk said. “While we were disappointed that we weren’t working in a structure that was the result of a meteorite hitting the planet three billion years ago, science is about advancing knowledge through discovery, and our understanding of the Earth’s ancient history continues to evolve. Our findings provide scientific data for resource companies and Greenlandic prospectors to find new mineral resources.”
The study, Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland, by Yakymchuk and an international team of scientists from Canada, Australia, Denmark, Greenland and the United Kingdom, appears in the journal Earth and Planetary Science Letters.
In the Media:
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Canadian-led team disproves 'world's oldest crater' discovery in Greenland, CTV News, March 11, 2021
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Suspicions on True Origin of World's Oldest 'Impact Crater' Have Now Been Confirmed, Science Alert, March 11, 2021
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The world's oldest crater from a meteorite isn't an impact crater after all, Science Daily, March 11, 2021
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'World's oldest impact crater' isn't an impact crater at all! 62-mile-wide Maniitsoq structure was created by geological processes 3 billion years ago and NOT a meteorite strike, scientists claim, The Daily Mail, March 11, 2021
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Oldest Crater of the World Isn't a Meteorite Crash Site, Here's What Geological Study Reveal, The Science Times, March 12, 2021
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It Turns Out That the World’s Oldest Impact Crater Isn’t an Impact Crater, Universe Today, March 16, 2021
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The world's oldest crater from a meteorite isn't an impact crater after all, Phys.org, March 11, 2021
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World's oldest meteor crater isn't what it seems, Live Science, March 23, 2021
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When Is a Crater Not a Crater?, Atlas Obscura, March 19, 2021
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Experts Baffled as Origin of World's Oldest Meteor Crater Disputed, Nature World News, March 23, 2021
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World's oldest meteor crater isn't what it seems, Space.com, March 25, 2021
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The supposedly oldest impact crater on Earth isn’t a crater after all, Massive Science, March 8, 2021