Two deep, underground scars in the earth’s crust lie in outback Australia and mark the remains of what scientists believe to be the world’s largest ever meteorite crater. Its diameter: over 250-miles. These two scars measure more than 120 miles in diameter each and are believed to represent the collision point of the meteorite which split in two before falling on Earth.
Initially, scientists had only discovered one of the two scars. At the time, they thought that the site represented the third largest crater ever discovered. The crater itself is no longer visible, however, experts have been studying samples from the twin scars which they obtained by drilling.
According to Dr. Andrew Glikson from the Australian National University School of Archaeology and Anthropology, the impact occurred some 300 million years ago. The two asteroids which finally struck Earth are believed to have been more than 10 kilometers across and such massive impacts may have caused the extinction of many life species on the planet at the time of the collision.
“Large impacts like these may have had a far more significant role in the Earth’s evolution than previously thought.”
The impact zone is located near the borders of Queensland, the Northern Territory and South Australia and is more than 19 miles deep. Geological processes have long buried the double-impact crater, however its imprint remains. And although such a massive impact is believed to have caused a massive extinction, Dr. Glikson cannot accurately identify the date of the impact especially since there are no extinction events matching the collision.
When compared to other famous asteroid craters, the Chicxulub crater for instance, which is believed to have caused the extinction of the dinosaurs, this double-impact crater is a monster. The Chicxulub asteroid is believed to have been 10 kilometer wide. Its crater’s diameter measures 110 miles, yet the impact zone of the Warburton Basin asteroid is more than twice the size of the Chicxulub crater.
Geothermal research actually revealed the crater. As researchers were drilling out rock samples from South Australia, they came across rocks that had been turned to glass (one of the tell-tale signs of such collisions). According to Dr. Glikson, the two deep domes in Earth’s crust are huge and stem from the planet’s crust rebounding as a result of the massive impact. This rebound caused rock from the mantle below to be brought towards the surface.
“I have a suspicion the impact could be older than 300 million years.”
Dr. Glikson said, noting that the rocks surrounding the site are as old as 600 million years old, although they are not accompanied by sediment layers which could provide evidence of a mass extinction. Normally, layers of sediments accompany large meteorite strikes. And while large amounts of debris were blasted into our planet’s atmosphere at the moment of impact, there is still much work to be done in order to uncover evidence of the devastating effects that the asteroid must have had.