Nature & Environment
Record-Breaking Asteroid Slammed into Australia Millions of Years Ago
Catherine Griffin
First Posted: Mar 23, 2015 09:51 AM EDT
Where did the largest asteroid impacts occur on our planet? It turns out that Australia holds the record. Scientists have discovered a 250-mile-wide impact zone from a huge meteorite that broke in two moments before it slammed into Earth.
The crater has long since disappeared. However, researchers have uncovered the twin scars of the impacts, which represent the largest impact zone ever found on Earth, hidden deep in our planet's crust. The impact zone itself was found during drilling as part of geothermal research in an area near the borders of South Australia, Queensland and the Northern Territory.
"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 Andrew Glikson, one of the researchers, in a news release. "Large impacts like these may have had a far more significant role in the Earth's evolution than previously thought."
That said, the exact date of the impacts remains unclear. The surrounding rocks are 300 to 600 million years old, but evidence of the type left by other meteorite strikes is lacking. For example, a large meteorite strike 66 million years ago sent up a plume of ash which can be found in the form of a layer of sediment of rocks around the world. This plume may have led to the extinction of a large proportion of life on the planet, including many dinosaur species. A similar layer, though, has not been found in sediments around 300 million years old.
"It's a mystery-we can't find an extinction event that matches these collisions," said Glikson. "I have a suspicion that the impact could be older than 300 million years."
While researchers do know these massive impacts occurred, they're not sure when. However, it's likely further research may reveal the true time period of these impacts.
The findings are published in the journal Tectonophysics.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
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First Posted: Mar 23, 2015 09:51 AM EDT
Where did the largest asteroid impacts occur on our planet? It turns out that Australia holds the record. Scientists have discovered a 250-mile-wide impact zone from a huge meteorite that broke in two moments before it slammed into Earth.
The crater has long since disappeared. However, researchers have uncovered the twin scars of the impacts, which represent the largest impact zone ever found on Earth, hidden deep in our planet's crust. The impact zone itself was found during drilling as part of geothermal research in an area near the borders of South Australia, Queensland and the Northern Territory.
"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 Andrew Glikson, one of the researchers, in a news release. "Large impacts like these may have had a far more significant role in the Earth's evolution than previously thought."
That said, the exact date of the impacts remains unclear. The surrounding rocks are 300 to 600 million years old, but evidence of the type left by other meteorite strikes is lacking. For example, a large meteorite strike 66 million years ago sent up a plume of ash which can be found in the form of a layer of sediment of rocks around the world. This plume may have led to the extinction of a large proportion of life on the planet, including many dinosaur species. A similar layer, though, has not been found in sediments around 300 million years old.
"It's a mystery-we can't find an extinction event that matches these collisions," said Glikson. "I have a suspicion that the impact could be older than 300 million years."
While researchers do know these massive impacts occurred, they're not sure when. However, it's likely further research may reveal the true time period of these impacts.
The findings are published in the journal Tectonophysics.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone