The planet's oldest meteor impact crater is not a crater at all, researchers explained in recent research proposing normal forces put the massive indent into the planet's surface. But the jury is however out.
The Maniitsoq Structure
The ambitious crater, named locally as the Maniitsoq structure, can be found 55 kilometers (34 miles) southeast of the city of Maniitsoq in Greenland. The structure is about 100 km (62 miles) in diameter and was built about 3 billion years ago, though its heritage has been doubted in recent years
Geologist Adam Garde, of the Geological Survey of Denmark and Greenland, and colleagues explained in 2012, that they had discovered proof that the Maniitsoq structure was formed by a meteor impact, dubbing it the first recorded instance of its kind in the world. Still, recent research calls into query the 2012 groups' discoveries.
The University of Waterloo in Canada geologist and lead author Chris Yakymchuk explained that after a long inquiry of the Maniitsoq area, they have not yet discovered proof of microscopic surprising deformation that is located in almost all other impact craters. "Their data suggest that the building in the place is the property of old plate tectonic activity, heating, and deformation about hundreds of millions of years." Still, Garde reported that he is not certain.
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The Meteorite
Garde and his colleagues determined that the Maniitsoq structure is an impact crater primarily because of the structure of rocks at its core, which they recorded in the journal Earth and Planetary Science Letters in 2012.
The scientists explained that the middle of those rocks and the way they had been exerted into the ground could be described only by the influence of a meteorite.
Chris explained that an impact origin was probable, with the data they had at the time and that the goal was to experiment on the effect hypothesis utilizing more data compiled with a larger array of procedures.
Other research had already clear several doubts on the 2012 discoveries, but Chris explained that he and his group came with an "open mind" about the structure's legacy when they began their studies in 2016.
Zircon Crystals
Their major proof against an impact origin arrives from an examination of zircon crystals - incredibly durable and minute layouts made up of zirconium silicate. The group assessed over 5,000 of these mineral grains and could not discover any proof - such as ruptures within the crystals - of them being destroyed by a significant impact.
Zircon crystals are microscopic time capsules that can catch the defect created from shock waves provoked during a meteorite impact. Chris explained that they did not discover any defect that suggested old shock waves crossed through these minerals.
Age of Impact
Lately, researchers have utilized these crystals to indicate that Earth's crust thrived rapidly at about the same time the Maniitsoq structures were created, recent reports suggest this kind of tectonic expansion spurt possibly formed the Maniitsoq structure.
When they began to integrate several field notes with data on the age of certain rock units, it started to guide them away from an impact crater heritage. Chris disclosed that the age they recovered was 40 million years younger than the suggested age of impact.
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