World's Largest Asteroid Found in Australia, Impacts Measuring 400KM Wide Found

Scientists have discovered a 400-km wide impact zone from a huge meteorite in Central Australia.

Calling it the largest impact zone ever found on earth, the crater from the impact that occurred millions of years ago had already disappeared. However, geophysicists found the twin scars of the impact hidden deep in the earth's crust.

"The two asteroids must each have been over 10 kilometers across – it would have been curtains for many life species on the planet at the time," said Dr. Andrew Glikson, the lead researcher from the Australian National University.

The impact zones were discovered during a drilling operation as part of a geothermal research in an area near the borders of South Australia, Queensland and the Northern Territory.

Glikson said the impact zones will play a role in studying the earth's evolution. "Large impacts like these may have had a far more significant role in the Earth's evolution than previously thought," he said.

The scientists don't know the exact date of the impact, but the surrounding rocks in area were estimated to be 300 to 600 million years old.

However, the scientists could not relate the impact zones to any extinction event like when a large meteorite struck the earth 68 million years ago that sent a plume of ash found as a layer of sediment in rocks around the world.

The plume was believed to have caused the extinction of life on earth including many dinosaur species.

"It's a mystery – we can't find an extinction event that matches these collisions. I have a suspicion the impact could be older than 300 million years," Glikson said.

The impact zones were found during a geothermal research project drilling more than two kilometers into the earth's crust.

The drill core had traces of rocks that had been turned to glass by the extreme temperature and pressure caused by a major impact.

The Australian National University said magnetic modelling of the deep crust in the area traced out bulges hidden deep in the Earth, rich in iron and magnesium, corresponding to the composition of the earth's mantle.

"There are two huge deep domes in the crust, formed by the Earth's crust rebounding after the huge impacts, and bringing up rock from the mantle below," he said.

The two impact zones total more than 400 kilometres across, in the Warburton Basin in Central Australia.