Meteorites: Sudbury Evidence

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Billions of years ago, a cataclysmic event took place in the region now know as Sudbury, in Ontario, Canada. And it’s only relatively recently that scientists have figured out what actually happened. I’m Jim Metzner, and this is the Pulse of the Planet.

“If you stand at Sudbury now, to the trained eye, you can tell that something catastrophic happened there a long time ago, but those signs are rather cryptic. And it’s for that reason that for many decades people have argued about what actually happened there, and it was only within the last 15 years or so that there’s been a widespread consensus that the event that occurred there was actually a meteorite impact.”

James Edward Mungall is an Associate Professor in the Department of Geology at the University of Toronto.

“You can go to Sudbury now and look at the place where we think that the meteorite impact basin was, which measures about 60 kilometers long by about 30 kilometers wide. But we think that the original basin was probably anywhere from 250 to 300 kilometers in diameter. That’s a very large basin. It was an actually an ocean of magma. It’s so big that if you stand in the middle of it, you can’t see the edges. So, if you go to Sudbury and start looking for signs of impact, you have to look at a lot of different places. And much of the evidence that we rely upon is microscopic in size. There are things there that you don’t find in places where there haven’t been impacts. For example, there are diamonds which are much smaller than a millimeter across, which were formed by the passage of a shockwave through carbon-rich rocks. There are crystals there which are smaller than you can see with the naked eye, which have been partly or completely transformed into glass by the passage of a shockwave. There’s a type of structure called a shatter cone, which are cone-shaped cracks in the rock. The only places that shatter cones have ever been observed are around meteorite impact sites and very close to the points of detonation of nuclear weapons.”

Please visit us on the web at pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation.

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Meteorites: Sudbury Evidence

Scientists are finding clues to what caused a cataclysmic explosion two billion years ago.
Air Date:01/31/2006
Scientist:
Transcript:

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Billions of years ago, a cataclysmic event took place in the region now know as Sudbury, in Ontario, Canada. And it's only relatively recently that scientists have figured out what actually happened. I'm Jim Metzner, and this is the Pulse of the Planet.

"If you stand at Sudbury now, to the trained eye, you can tell that something catastrophic happened there a long time ago, but those signs are rather cryptic. And it’s for that reason that for many decades people have argued about what actually happened there, and it was only within the last 15 years or so that there’s been a widespread consensus that the event that occurred there was actually a meteorite impact."

James Edward Mungall is an Associate Professor in the Department of Geology at the University of Toronto.

"You can go to Sudbury now and look at the place where we think that the meteorite impact basin was, which measures about 60 kilometers long by about 30 kilometers wide. But we think that the original basin was probably anywhere from 250 to 300 kilometers in diameter. That’s a very large basin. It was an actually an ocean of magma. It’s so big that if you stand in the middle of it, you can’t see the edges. So, if you go to Sudbury and start looking for signs of impact, you have to look at a lot of different places. And much of the evidence that we rely upon is microscopic in size. There are things there that you don’t find in places where there haven’t been impacts. For example, there are diamonds which are much smaller than a millimeter across, which were formed by the passage of a shockwave through carbon-rich rocks. There are crystals there which are smaller than you can see with the naked eye, which have been partly or completely transformed into glass by the passage of a shockwave. There’s a type of structure called a shatter cone, which are cone-shaped cracks in the rock. The only places that shatter cones have ever been observed are around meteorite impact sites and very close to the points of detonation of nuclear weapons."


Please visit us on the web at pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation.

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