Australian crater linked to mass extinction of dinosaurs

SCIENTISTS have discovered signs of a large impact crater buried off the coast of Australia that may be linked to the biggest extinction event in Earth’s history — the “Great Dying” 250 million years ago.

Many scientists have long blamed a massive meteor near Mexico's Yucatan Peninsula for wiping out the dinosaurs 65 million years ago.

What caused the far earlier and larger Permian-Triassic extinction when about 90% of all species disappeared is subject to sharper debate.

The leading theory is that the extinction actually stretched over thousands of years, triggered by volcanic eruptions. A massive flow of molten rock over what is now Siberia injected tons of toxic gases into the atmosphere, gradually changing the planet's climate.

The new study, published today by the journal Science, backs another theory that a massive asteroid strike played at least some role, too.

The researchers cite clues that an impact crater the right age and perhaps 120 miles wide is buried off Australia's northwest corner. They're calling it the Bedout crater (pronounced Beh-doo.)

"We think that mass extinctions may be defined by catastrophes like impact and volcanism occurring synchronously in time," lead researcher Luann Becker of the University of California, Santa Barbara, said.