Impact crater Yarrabubba, located in the Western part of Australia was formed 2,229 billion years ago, scientists have found.
a New study published in the journal Nature Communications, showed that he is the oldest known meteorite in the world, and its age is about half of the time of existence of the Earth.
in addition, Yarrabubba 200 million years older than any other similar formations on the planet.
According to assumptions of specialists, the fall of the meteorite in Australia could significantly change the Earth’s climate, bringing the end of one of the oldest and most extensive glaciation, which began and ended in the Paleoproterozoic.
Scientists have long suspected that Yarrabubba formed several billion years ago, but to determine the age of such ancient craters difficult. They are usually poorly preserved due to erosion and earthquakes.
To accurately estimate the age of Yarrabubba, the team studied the minerals monazite and zircon, found in the so-called points of shock recrystallization where a meteorite impact has changed the structure of the minerals. They need scientists found a microscopic grain.
They were dated using the uranium-thorium-lead method and to accurately determine the age of 70-kilometer-wide crater. It turned out the meteorite fell at about the same time when our planet is out of phase “Earth-snowball.”
“Glacial deposits were absent in the rocks for about 400 million years after the appearance of Yarrabubba,” notes Professor Chris Kirkland’s (Chris Kirkland) from the School of Earth Sciences and planets, University kertina.
the Researchers suggest that the place where the meteorite fell, was covered with ice, as much of the Land at the time. Because of the powerful shot into the atmosphere could get up to half a million tons of vaporized ice. But water vapor is even more “effective” greenhouse gas than carbon dioxide. It could make the climate much warmer.
However, with such a Hypothesis not everyone agrees. So, Professor Tim burrows (Tim Barrows) from the University of Wollongong who did not participate in this study, considers it nothing more than a beautiful theory. The fact that there is no evidence that the place of the meteorite fall was attended by a glacier.
However, the accuracy of the calculation of the age of the crater burrows impressed. The same technique described in detail in the journal Nature Communications, it proposes to use to determine the age of other ancient craters.
earlier, “News.Science” (nauka.vesti.ru) wrote about how the Popigai crater in Siberia, scientists have linked the mass extinction, as well as that of the earth’s craters are traces of the fall of asteroids with satellites.
Text: To.Science
