The largest asteroid impact zone on Earth has been identified by scientists after two collision sites were discovered in central Australia.
Researchers from Australian National University (ANU) said on Tuesday they had detected a 400 kilometer-wide zone believed to have been caused by a meteorite splitting in two millions of years ago.
The research has been published in the academic journal Tectonophysics and revealed that the twin deep domes were discovered during drilling as part of geothermal research in a surface area that straddles the borders of South Australia, Queensland and the Northern Territory.
ANU researcher Dr Andrew Glikson said the spectacular crash would have destroyed anything in its path.
"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," he said in a statement.
Glikson was not sure when the event occurred, however surrounding rocks are between 300-600 million years old.
"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," he said.
"Large impacts like these may have had a far more significant role in the Earth's evolution than previously thought," he added.