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Waspie_Dwarf

Killer Crater Found In Antarctica

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Large Impact Crater Founder Under Antarctic Ice


The Ohio State University press release is reproduced below:


BIG BANG IN ANTARCTICA -- KILLER CRATER FOUND UNDER ICE
Ancient mega-catastrophe paved way for the dinosaurs, spawned Australian continent


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COLUMBUS, Ohio -- Planetary scientists have found evidence of a meteor impact much larger and earlier than the one that killed the dinosaurs -- an impact that they believe caused the biggest mass extinction in Earth's history.

The 300-mile-wide crater lies hidden more than a mile beneath the East Antarctic Ice Sheet. And the gravity measurements that reveal its existence suggest that it could date back about 250 million years -- the time of the Permian-Triassic extinction, when almost all animal life on Earth died out.

user posted image
Ralph von Frese

Its size and location -- in the Wilkes Land region of East Antarctica, south of Australia -- also suggest that it could have begun the breakup of the Gondwana supercontinent by creating the tectonic rift that pushed Australia northward.

Scientists believe that the Permian-Triassic extinction paved the way for the dinosaurs to rise to prominence. The Wilkes Land crater is more than twice the size of the Chicxulub crater in the Yucatan peninsula, which marks the impact that may have ultimately killed the dinosaurs 65 million years ago. The Chicxulub meteor is thought to have been 6 miles wide, while the Wilkes Land meteor could have been up to 30 miles wide -- four or five times wider.

"This Wilkes Land impact is much bigger than the impact that killed the dinosaurs, and probably would have caused catastrophic damage at the time," said Ralph von Frese, a professor of geological sciences at Ohio State University.

He and Laramie Potts, a postdoctoral researcher in geological sciences, led the team that discovered the crater. They collaborated with other Ohio State and NASA scientists, as well as international partners from Russia and Korea. They reported their preliminary results in a recent poster session at the American Geophysical Union Joint Assembly meeting in Baltimore.

The scientists used gravity fluctuations measured by NASA's GRACE satellites to peer beneath Antarctica's icy surface, and found a 200-mile-wide plug of mantle material -- a mass concentration, or "mascon" in geological parlance -- that had risen up into the Earth's crust.

Mascons are the planetary equivalent of a bump on the head. They form where large objects slam into a planet's surface. Upon impact, the denser mantle layer bounces up into the overlying crust, which holds it in place beneath the crater.

When the scientists overlaid their gravity image with airborne radar images of the ground beneath the ice, they found the mascon perfectly centered inside a circular ridge some 300 miles wide -- a crater easily large enough to hold the state of Ohio.

Taken alone, the ridge structure wouldn't prove anything. But to von Frese, the addition of the mascon means "impact." Years of studying similar impacts on the moon have honed his ability to find them.

"If I saw this same mascon signal on the moon, I'd expect to see a crater around it," he said. "And when we looked at the ice-probing airborne radar, there it was."

"There are at least 20 impact craters this size or larger on the moon, so it is not surprising to find one here," he continued. "The active geology of the Earth likely scrubbed its surface clean of many more."

He and Potts admitted that such signals are open to interpretation. Even with radar and gravity measurements, scientists are only just beginning to understand what's happening inside the planet. Still, von Frese said that the circumstances of the radar and mascon signals support their interpretation.

"We compared two completely different data sets taken under different conditions, and they matched up," he said.

To estimate when the impact took place, the scientists took a clue from the fact that the mascon is still visible.

"On the moon, you can look at craters, and the mascons are still there," von Frese said. "But on Earth, it's unusual to find mascons, because the planet is geologically active. The interior eventually recovers and the mascon goes away." He cited the very large and much older Vredefort crater in South Africa that must have once had a mascon, but no evidence of it can be seen now.

"Based on what we know about the geologic history of the region, this Wilkes Land mascon formed recently by geologic standards -- probably about 250 million years ago," he said. "In another half a billion years, the Wilkes Land mascon will probably disappear, too."

Approximately 100 million years ago, Australia split from the ancient Gondwana supercontinent and began drifting north, pushed away by the expansion of a rift valley into the eastern Indian Ocean. The rift cuts directly through the crater, so the impact may have helped the rift to form, von Frese said.

But the more immediate effects of the impact would have devastated life on Earth.

"All the environmental changes that would have resulted from the impact would have created a highly caustic environment that was really hard to endure. So it makes sense that a lot of life went extinct at that time," he said.

He and Potts would like to go to Antarctica to confirm the finding. The best evidence would come from the rocks within the crater. Since the cost of drilling through more than a mile of ice to reach these rocks directly is prohibitive, they want to hunt for them at the base of the ice along the coast where the ice streams are pushing scoured rock into the sea. Airborne gravity and magnetic surveys would also be very useful for testing their interpretation of the satellite data, they said.

NSF and NASA funded this work. Collaborators included Stuart Wells and Orlando Hernandez, graduate students in geological sciences at Ohio State; Luis Gaya-Piqué and Hyung Rae Kim, both of NASA's Goddard Space Flight Center; Alexander Golynsky of the All-Russia Research Institute for Geology and Mineral Resources of the World Ocean; and Jeong Woo Kim and Jong Sun Hwang, both of Sejong University in Korea.

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[attachmentid=26085]
Above, thickness of the Earth's crust across Antarctica . Thicker crust appears red. The location of the Wilkes Land crater is circled (below right of center). Image courtesy of Ohio State University.

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Above, GRACE-measured gravity fluctuations beneath East Antarctica . Denser regions appear more red; the location of the Wilkes Land crater is circled (above center). Image courtesy of Ohio State University.

[attachmentid=26087]
Above, airborne radar image of land elevation in East Antarctica . Higher elevations appear red, purple, and white; the location of the Wilkes Land crater is circled (above center). Image courtesy of Ohio State University . An inset of the Chicxulub crater is included for comparison. Image courtesy of Ohio State University.

[attachmentid=26088]
Above, combined image of gravity fluctuations and airborne radar in the Wilkes Land region of East Antarctica . The edges of the crater are colored red and blue; a concentration of mantle material is colored orange (center). Image courtesy of Ohio State University.
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Below, size comparison of large craters of the solar system. The Wilkes Land crater is third from left. Image courtesy of Ohio State University. [Larger version available here.]
[attachmentid=26089]



Source: Ohio State University press release

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so they finnaly think they found the reason for the permian- triassic mass extinction :) mostly they always thought they wouldnt find any traces cuz of all the tectonic movements lol

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The mass extinction was caused by volcanos and meathane wrming up the planet by nearly 10 degrees.

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The mass extinction was caused by volcanos and meathane wrming up the planet by nearly 10 degrees.

That is one theory Master Sage. This impact is another.

It is impossible to be certain about things which occured a quarter of a billion years ago.

Not all experts are convinced that the Chixulub impact was responsible for the mass extinction of the dinosaurs, and that was only 65 million years ago so they will certainly have multiple theories for the Permian-Triassic extinction.

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Sometimes I think that Scientists really have NO IDEA...

They just have a heap of theories on everything, until something else comes along to prove them wrong, and then they go... Oh of course, so thats how it is... So then that new theory sticks around and is claimed as fact, until something else pops ups that ruins their new theory......

I'm not blaming them for having theories and ideas on how our big wide world works, in history present and future terms, but they should admit that they haven't a clue most of the time. They just guess and make their result fit their theory...

Just My Thoughts...

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Sometimes I think that Scientists really have NO IDEA...

They just have a heap of theories on everything, until something else comes along to prove them wrong, and then they go... Oh of course, so thats how it is... So then that new theory sticks around and is claimed as fact, until something else pops ups that ruins their new theory......

I'm not blaming them for having theories and ideas on how our big wide world works, in history present and future terms, but they should admit that they haven't a clue most of the time. They just guess and make their result fit their theory...

Just My Thoughts...

cuz they dont, its all theorys until proven real

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Posted (edited)

Sometimes I think that Scientists really have NO IDEA...

They just have a heap of theories on everything, until something else comes along to prove them wrong, and then they go... Oh of course, so thats how it is... So then that new theory sticks around and is claimed as fact, until something else pops ups that ruins their new theory......

I'm not blaming them for having theories and ideas on how our big wide world works, in history present and future terms, but they should admit that they haven't a clue most of the time. They just guess and make their result fit their theory...

Just My Thoughts...

Why is it that people with little or no understanding of scientific method assume that because science doesn't know everything it must know nothing?

Science doesn't claim to have all the answers. It is a search for the truth. What scientists do is try to make their theories fit the results, not the other way around. Sometimes there are multiple theories simply because they both fit the results. As more is learned a theory may fall by the wayside and another replaces it. This is why scientists call them theories, if you want to beleive in absolute truths take up theology.

Sadly there seems to be a growing ignorance of the way that science works. People seem to be totally oblivious to the fact that virtually everything in the modern world has been created by some "clueless" scientist or engineer.

Edited by Waspie_Dwarf

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The mass extinction was caused by volcanos and meathane wrming up the planet by nearly 10 degrees

That is one supported theory..A large meteor impact could of caused the Siberian Traps :tu:

Why is it that people with little or no understanding of scientific method assume that because science doesn't know everything it must know nothing?

It disgusts me...

Science doesn't claim to have all the answers. It is a search for the truth. What scientists do is try to make their theories fit the results, not the other way around. Sometimes there are multiple theories simply because they both fit the results. As more is learned a theory may fall by the wayside and another replaces it. This is why scientists call them theories, if you want to beleive in absolute truths take up theology.

Sadly there seems to be a growing ignorance of the way that science works. People seem to be totally oblivious to the fact that virtually everything in the modern world has been created by some "clueless" scientist or engineer.

Couldn't of said it better myself, Waspie :tu:

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Sadly there seems to be a growing ignorance of the way that science works. People seem to be totally oblivious to the fact that virtually everything in the modern world has been created by some "clueless" scientist or engineer.

Pardon my growing ignorance.... Yes your right scientists have 'invented' things... I never said they hadn't. It's their understanding of the world itself that they don't understand.

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Pardon my growing ignorance....

That was a genaral statement, not aimed at you personally, just as I am sure that your accusation of cluelessness was not aimed at me personally (I have been a professional scientist for more than 20 years).

It's their understanding of the world itself that they don't understand.

They don't understand their own understanding? That I don't understand.

If you are trying to say that scientists don't understand the real world then you couldn't be further from the truth. It is the very process of eliminating incorrect theories that widens their understanding as Sir Arthur Conan Doyle's Sherlock Holmes would say,

When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

A comparison between Holmes and science is a good one. Science is detective work. Observations are made. From these observations hypothesis are formed. These hypothesis are tested by more measurement and more observation. If the observations agree with those predicted by the hypothesis then it is accepted by the scientific and becomes a theory. If it does not fit it is rejected. This is the way of understanding, not of ignorance.

You accept that scientists have made advances. If they are "clueless" how did they do this? Lucky guess? Magic? Or just maybe they actually know what they are doing.

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You know its not an either or type of thing, one theory about the dinosaurs extinction was that they were going through a transistion period due to climate shifts, when the asteroid hit and killed them off. A similar thing could have occured with the P-T extinction, that the asteroid hit right in the middle of other climate changes.

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Posted (edited)

You know its not an either or type of thing, one theory about the dinosaurs extinction was that they were going through a transistion period due to climate shifts, when the asteroid hit and killed them off. A similar thing could have occured with the P-T extinction, that the asteroid hit right in the middle of other climate changes.

That's very true.

It is always easy to assume that because 2 events occur at around the same time that they must be connected. It is not alwys the case. It is possible that neither the impact or the climate change caused the extinction, but another factor not even considered.

I suspect that with the vast amount of time that has passed we will never know for sure.

By the way Avinash, thanks for getting this thread back on subject.

Edited by Waspie_Dwarf

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Very interesting topic, thats scared me if that would happen again!

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What I think happened is that the meteor struck Antarctica (which was close to Russia). This then triggered a series of massive volcanic eruptions...including the Siberian Traps. This then in turned changed the climate drastically, warming the earth.

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What I think happened is that the meteor struck Antarctica (which was close to Russia). This then triggered a series of massive volcanic eruptions...including the Siberian Traps. This then in turned changed the climate drastically, warming the earth.

Right, the volcanos teroticaly made about a 4 degree difrence. Then that heat unacned underwater metahne, which lead to further climate change.

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Right, the volcanos teroticaly made about a 4 degree difrence. Then that heat unacned underwater metahne, which lead to further climate change.

A question rather than a personal belief -

The impact and subsequent volcanicity would send a fair amount of material into the atmosphere.

With the sun blocked a nuclear winter results, reducing global temperatures.

so....

Impact and World temperature rises say 5deg C (based on no research on my part)

5 years (or whatever) later world cools 10 degC

Continued eruptions increase by 0.1 deg C every 500 years

Clensing of atmosphere reduced the nuclear winter increase by 0.1 deg C every 100 years

Stable world, but with pollutants in atmosphere temperature some 5-10 deg C

Next 100,000 years...... World balances out.

It would not be a case that increased temperature happened, but there was no stable environment above sea level for several 100k years.

Just thinking out aloud.

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