World’s oldest meteorite impact is 43-mile crater in Australia – created 2BILLION years ago
THE oldest crater on Earth has been precisely dated and scientists think the impact could have changed the world’s climate.
Western Australia’s Yarrabubba crater is now thought to be 200 million years older than the next oldest crater on Earth.
Researchers re-dated the site with new technological methods.
They measured the age of shocked minerals within the crater and determined it was created by a meteorite 2.23billion years ago.
This would make it around half the age of our 4.5billion-year-old Earth.
The crater has long been regarded as one of Earth’s oldest but a precise age was unknown until now.
Dating craters can be very difficult due to changes in the Earth’s surface over time.
The research team thinks the meteor struck at a time when glaciers were forming all over the Earth and Australia was largely covered in ice.
Simulations have indicated that the meteorite hit a continental ice sheet and threw 5,000 trillion kilograms of water vapour into the atmosphere.
The scientists note that such an impact would have drastically changed the Earth’s climate and may have even caused a greenhouse effect period known as “Snowball Earth”.
The researcher were based at Curtin University in Perth.
Professor Chris Kirkland, who worked on the study, said: “Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn’t well determined.”
“Now we know the Yarrabubba crater was made right at the end of what’s commonly referred to as the early Snowball Earth – a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions.”
The researchers can support their climate changing theory with the fact the Yarrabubba impact appears to coincide with the disappearance of glacial deposits.
Associate Professor Nicholas Timms said: “This twist of fate suggests that the large meteorite impact may have influenced global climate.”
The study could have a significant impact for future crater investigations.
Curtin University’s Dr Aaron Cavosie said: “Our findings highlight that acquiring precise ages of known impact craters is important – this one sat in plain sight for nearly two decade before its significance was realised.
“Yarrabubba is about half the age of the Earth and it raises the question of whether all older impact craters have been eroded or if they are still out there waiting to be discovered.”
This research has been published in Nature Communications.
What's the difference between an asteroid, meteor and comet?
Here's what you need to know, according to Nasa...
- Asteroid: An asteroid is a small rocky body that orbits the Sun. Most are found in the asteroid belt (between Mars and Jupiter) but they can be found anywhere (including in a path that can impact Earth)
- Meteoroid: When two asteroids hit each other, the small chunks that break off are called meteoroids
- Meteor: If a meteoroid enters the Earth’s atmosphere, it begins to vapourise and then becomes a meteor. On Earth, it’ll look like a streak of light in the sky, because the rock is burning up
- Meteorite: If a meteoroid doesn’t vapourise completely and survives the trip through Earth’s atmosphere, it can land on the Earth. At that point, it becomes a meteorite
- Comet: Like asteroids, a comet orbits the Sun. However rather than being made mostly of rock, a comet contains lots of ice and gas, which can result in amazing tails forming behind them (thanks to the ice and dust vapourising)
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