Scientists confirm that Australia’s Yarrabubba impact crater is the oldest in the world
Oldest meteorite impact recorded in the world: a 43-mile-wide crater in Western Australia was created by an asteroid attack 2,229 BILLION years ago
- The Yarrabubba crater in WA are the remains of the first known asteroid attack on Earth
- The scientists used the analysis of isotopic minerals to determine their age: 2,229 billion years.
- The oldest asteroid attack on Earth has also been linked to the end of glacial conditions
The oldest asteroid attack on Earth was in Yarrabubba, in the interior of Western Australia, about 2,229 billion years ago, Australian scientists confirmed.
The Curtin University team in Perth used isotopic mineral analysis to calculate the precise age of the impact crater 43 miles wide for the first time.
The asteroid attack that created the crater occurred 200 million years before the next oldest impact on Vredefort in South Africa.
Yarrabubba’s impact structure is considered one of the oldest on Earth, but until now it lacked a precise age.
Barlangi Rock, near where the Curtin researchers collected their samples for analysis
“Yarrabubba, which is between Sandstone and Meekatharra in downtown WA, had been recognized as an impact structure for many years, but its age was not well determined,” said Professor Chris Kirkland of the University of Curtin.
The Earth has a constantly changing surface due to tectonics and erosion, which means that very old impact craters are difficult to identify.
The team analyzed the zircon and monazite minerals that were “recrystallized by shock” by the impact of the asteroid, at the base of the eroded crater to determine the exact age of Yarrabubba.
With 2,200 million years, Yarrabubba is about half the age of the Earth: 4.5 billion years.
Zircon, a common colorful gemstone in the earth’s crust, found in the Yarrabubba crater
According to the researchers, the moment of the impact created by the crater may even have helped take planet Earth out of deep freezing.
“We now know that the Yarrabubba crater was made just at the end of what is commonly known as the Early Snowball Land, a time when the atmosphere and oceans evolved and became more oxygenated and when rocks deposited on many continents they registered glacial conditions, “said Professor Kirkland.
Yarrabubba’s impact also coincided with the disappearance of glacial deposits, which are absent in the rock record for 400 million years since the impact.
“This turn of fate suggests that the great impact of the meteorite may have influenced the global climate,” said associate professor Nicholas Timms.
The team’s calculations indicated that an impact on an ice-covered continent could have sent half a billion tons of water vapor to the atmosphere, potentially playing a role in modifying Earth’s climate.
“This finding raises the question of whether this impact may have tipped the balance enough to end glacial conditions,” said Professor Timms.
The asteroid may have landed in an ice-covered landscape, vaporizing a large volume of ice in the atmosphere and producing the 43-mile crater in the rocks below what we see today.
The study could be important for future discoveries of impact craters, some of which may be even older than Yarrabubba, which was first reported in 2003.
“Our findings highlight that the acquisition of precise ages of known impact craters is important: this was visible for almost two decades before its importance materialized,” said Dr. Aaron Cavosie of the University of Curtin.
“Yarrabubba is about half the age of Earth and raises the question of whether all the older impact craters have eroded or are still out there waiting to be discovered.”
The team says that while the material thrown from an impact crater found in parts of Australia and Africa was previously identified as older than 2 billion years ago, its corresponding craters could not be identified.
The research team, which also included Timmons Erickson of NASA’s Astromaterials Research and Exploration Science division, published his study in Nature Communications.
WHAT IS THE THEORY OF SNOWBALL LAND?
For millions of years, more than 640 million years ago, the Earth was wrapped in ice.
At that time, most of the land was grouped around the equator, but the glaciers left their mark on the rocks even there.
No one knows what caused the Earth to freeze, but once it did, the bright white surface of the ice reflected the heat and maintained the ‘snowball’ conditions, until the CO2 released by the volcanoes created a greenhouse effect. strong enough to melt the ice.
If the ice had covered the entire planet, life could have died out. But there is evidence that muddy pools survived during this period, and primitive but resilient life forms survived in the pools.
When the Earth unfroze, life exploded across the planet in an explosion of evolution.
We can owe our existence to this Snowball Earth event.