The world’s oldest meteor crater isn’t an impact crater after all

Several years after scientists discovered what was believed to be the oldest meteorite crater on the planet, another team discovered that it was actually the result of normal geological processes.

During fieldwork at the Archean Maniitsoq Structure in Greenland, an international team of scientists led by Chris Yakymchuk of the University of Waterloo discovered that the features of this region are incompatible with an impact crater. In 2012, another team identified it as the remnant of a three billion year old meteor crater.

“Zircon crystals in rock are like little time capsules,” said Yakymchuk, a professor in the Department of Earth and Environmental Sciences at Waterloo. “They preserve the old damage from the shock waves you get from a meteor impact. We didn’t find any such damage in them.”

Additionally, there are several places where rocks have melted and recrystallized deep within the Earth. This process – called metamorphism – would occur almost instantly if produced by an impact. The Waterloo-led team discovered that this happened 40 million years later than the previous group had proposed.

“We went there to explore the area for potential mineral exploration, and it was through careful examination of the area and the data collected since 2012 that we concluded that the features are incompatible with a meteorite impact.” , Yakymchuk said. “Although we were disappointed not to work in a structure that was the result of a meteorite hitting the planet three billion years ago, the science is to advance knowledge through discovery, and our understanding of Earth’s ancient history continues to evolve. The findings provide scientific data for resource companies and Greenlandic prospectors to find new mineral resources. “

The study, stirred not shaken; critical appraisal of an Archean meteorite impact project 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.