Rock 300m years ago changed Earth's face
Source: Agencies |
February 16, 2013, Saturday
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Print Edition
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A STRIKE from a big asteroid more than 300 million years ago left a gigantic impact zone buried in Australia and changed the face of the Earth, researchers said yesterday.
"The dust and greenhouse gases released from the crater, the seismic shock and the initial fireball would have incinerated large parts of the Earth," said Andrew Glikson, who is a visiting fellow at the Australian National University.
The asteroid was bigger than 10 kilometers in diameter, while the impact zone itself is estimated to have been larger than 200 kilometers - making it the third-largest impact zone in the world.
"The greenhouse gases would stay in the atmosphere for tens of thousands of years," Glikson said.
The discovery was made after another researcher alerted Glikson to some unusual mineral deposits in the East Warburton Basin in South Australia.
Glikson and colleagues analyzed quartz grains drawn from deep beneath the Earth's surface in research that started in 2010.
The crater itself was recently identified, he added.
The strike may have been part of an asteroid impact cluster that caused an era of mass extinction, wiping out primitive coral reefs and other species, added Glikson, co-author of a study published in the journal Tectonophysics.
The impact happened before the dinosaurs, he said.
The announcement of the discovery came just before a newly discovered asteroid about half the size of a football field was set to pass some 27,600 kilometers from Earth.
"The dust and greenhouse gases released from the crater, the seismic shock and the initial fireball would have incinerated large parts of the Earth," said Andrew Glikson, who is a visiting fellow at the Australian National University.
The asteroid was bigger than 10 kilometers in diameter, while the impact zone itself is estimated to have been larger than 200 kilometers - making it the third-largest impact zone in the world.
"The greenhouse gases would stay in the atmosphere for tens of thousands of years," Glikson said.
The discovery was made after another researcher alerted Glikson to some unusual mineral deposits in the East Warburton Basin in South Australia.
Glikson and colleagues analyzed quartz grains drawn from deep beneath the Earth's surface in research that started in 2010.
The crater itself was recently identified, he added.
The strike may have been part of an asteroid impact cluster that caused an era of mass extinction, wiping out primitive coral reefs and other species, added Glikson, co-author of a study published in the journal Tectonophysics.
The impact happened before the dinosaurs, he said.
The announcement of the discovery came just before a newly discovered asteroid about half the size of a football field was set to pass some 27,600 kilometers from Earth.
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