Five years ago, a group of researchers from the University of Curtinin Australiadetermined that in that country it was he crater of impact of meteorite older in the world. Although it is no longer visible for the time elapsed, it was encrypted in 2.2 billion years His age and, according to the study published then in Nature Communications, the impact of the meteorite contributed to ending the first ice age.
Now, a group of researchers from the same university and again headed by the geologist Christopher L. Kirkland has discovered a meteorite crater even olderwhich dates back to 3.5 billion years ago And it has been made with the title of being the oldest known on the planet, in the region of Pilbarain Western Australia.
‘Before our discovery, the oldest impact crater was 2.2 billion years old, so this is, by farthe oldest known crater ever found on Earth‘, he says Tim JohnsonGeologist at the University of Curtin and co -author of the study, in a statement. The finding is detailed in a recent new study also published in Nature Communications.
The researchers came to this discovery trying to understand how the first continents formed more than 3,000 million years ago
Kirkland team defends that Great meteorite collisions they could have caused the land mantle to form ‘masses’ of volcanic material that, over time, they became In continental cortex. However, to sustain their theory they needed find evidence of a meteorite impact that coincided with that temporal line, which they achieved.
The test is the shipyard cones
‘The crater was exactly where we expected it to be,’ the researchers point out in an article in The Conversation. But the team did not find a giant crater basin -3,500 million years is enough for erosion to do its job; Instead, they found the next best option: a rock formation known as shipyard cones In an area of the Pilbara region called the North Pole Dome.
These shipyard cones are geological structures that are only generated under the immense pressures caused by a meteoric impact.
‘It’s these Beautiful and delicate structures That they look a bit like a inverted bádminton pen with the upper broken part, ‘explains Johnson. ‘Cones that point up with delicate feather -shaped characteristics. The only way you can form those shipyard cones in natural rocks is from a great impact of meteorite‘.
Impact at 36,000 km/h
This meteorite would have hit the earth more than 36,000 kilometers per hour, spreading debris throughout the planet and creating A crater of more than 100 kilometers in diameter.
In addition, ‘discovering this impact and finding others from the same period could explain a lot about how life could have begun, since Impact craters created favorable environments for microbial life, as hot water pools‘, says Kirkland.