Meteor shards linked to massive extinction

International Herald Tribune ^ | 21 November 2003 | Kenneth Chang

[balrog666]

Fragments may be 250 million years old

About three dozen microscopic shards of rock unearthed in Antarctica may be the fragments of a meteor that killed most of life on earth 250 million years ago, scientists reported Friday. .

The shards bolster theories that meteors caused several of the mass extinctions in earth's history when large numbers of species died out almost simultaneously. Most scientists agree that the most recent major mass extinction 65 million years ago, which killed off the dinosaurs, was caused when a meteor struck the earth near the Yucatán Peninsula of Mexico. .

The extinction 250 million years ago, known as the Permian-Triassic boundary, was the largest extinction of all. More than 90 percent of species living in the oceans and 70 percent of those on land disappeared. .

At present, the primary suspected cause for the Permian-Triassic extinction is giant volcanic eruptions in Siberia, which might have induced catastrophic ecological changes. .

Writing in Friday's issue of the journal Science, the researchers report that they found the meteorite fragments in rocks in Antarctica that date to the Permian-Triassic boundary. The mineral composition of the fragments, each less than one-fiftieth of an inch, or roughly half a millimeter, wide, correspond to that of certain meteorites and is like nothing found naturally on earth, they reported. .

In addition, the scientists said, the same rocks had previously yielded soccer-ball-shaped molecules known as buckyballs containing extraterrestrial gases as well as grains of quartz with fractures that indicate they had been hit with a tremendous shock. .

"Clearly, this evidence points toward a major impact at the Permian-Triassic boundary," said Asish Basu, a professor of earth and environmental sciences at the University of Rochester in New York and lead author of the Science paper. That, he said, is "the most reasonable interpretation." .

The same researchers will report at a American Geological Union meeting next week in San Francisco that they have also found tiny metal spheres they believe were part of the earth's crust and melted by the impact. .

Others are not yet convinced. Eldridge Moores, an emeritus professor of geology at the University of California at Davis, described the meteorite fragments as "the most interesting evidence for a meteorite event at this boundary that I've seen so far." .

But, he added, while the evidence for the dinosaur-killing meteor 65 million years ago is a convincing 10 on a 1-to-10 scale, the evidence for a killer meteor at the Permian-Triassic boundary is not nearly as solid. "I think it's now up to 3 or 4," he said. "It's not 9 or 10." .

Douglas Erwin of the National Museum of Natural History in Washington said, "It's suggestive, but it's hardly compelling." Each piece of evidence offered so far has not by itself been compelling. .

The description of shocked quartz, he said, was tentative, even by the researcher who reported it, and other scientists have failed to reproduce the findings of buckyballs and extraterrestrial gases. If a meteor caused this largest of all extinctions, "I find it remarkable that there's so little evidence," Erwin said. .

If the evidence for an impact does become more compelling, that would raise another geological mystery: whether meteor impacts can set off gigantic volcanic eruptions. Huge eruptions in India coincided with the Yucatán meteor impact 65 million years ago. .

To date, most geologists have argued that meteors are not powerful enough to crack the earth's crust. Basu, who is strongly convinced that a meteor struck the Earth 250 million years ago, believes coincidence is not likely. "There has to be a connection," he said.

[DannyTN]

Pinging all meteorists and craterists. Calderists, cometists, and asteroidists too?

What about fragmentists, shardists and buckyballers?

[Orion78]

Perhaps this is what kick started the giant volcanoes on Mars. Roughly on the opposite side of the planet is the giant crater Hellas Planitia. I have often wondered when looking at a Mars map if there is a connection between the two.

[PatrickHenry]

where do you suppose the craters on the Earth and the Moon and Mars and Venus and Mercury come from?

The same place the earth, the moon, etc. all come from. Why should craters have a separate origin?

[Orion78]

So are you suggesting that all craters on all planetary bodies were formed at the same time durring the solar systems creation?

[PatrickHenry]

So are you suggesting that all craters on all planetary bodies were formed at the same time durring the solar systems creation?

I'm just sitting back, enjoying the fact that you have the burden of proving your craterist theory -- or rather, speculation. You say that rocks fall from the sky and cause craters? Okay. You've said it. Now what does that accomplish?

[Orion78]

LOL, Ok, well, if you want to play hard ball. Here ya go.

NASA Solves Half-Century Old Moon Mystery

[PatrickHenry]

Yes. Observe that the article admits that this, if true, would be an account of "the first and only human in history to witness and document the impact of an asteroid-sized body impacting the Moon's scarred exterior." And then it took 50 years to find what they claim is a likely crater to match up with this alleged observation by an amateur. Imagine ... they were actually able to find a crater on the moon! And suddenly, based on this "evidence," craterism is proved! Right. One dubious data point. Whoopie!!

However, even in the unlikely case that this actually was an observed cratering event, please note that it's a small crater, and it's on the moon! No atmosphere. Earth is a different situation. There are no observed instances of craterism on earth. None at all.

[Orion78]

Ok deny deny deny... Then what do you suppose caused these explosions on the moon witnessed simultaneously by mutiple observers?

November 18th (UT) Lunar Impacts

[PatrickHenry]

Those are the worst photos I've ever seen. There's more evidence for alien abductions than there is for meteor craters!

[U S Army EOD]

After reading reason number 8 I finally figured out why I have such a rotten personality.

[U S Army EOD]

Not me, maybe.

[U S Army EOD]

How do you know it wasn't caused by a very bad case of planet acne?

[U S Army EOD]

When I was sailing my sailboat back from England in 1978 we had one come in at night when we were between the Canaries and the BVI's. I was below deck and the sky lit up like someone was shinning a spot light on the boat. It was quite a sight.

[null and void]

There are no observed instances of craterism on earth. None at all.

Watch mecca for future developments...

[U S Army EOD]

Normally a big hole in the ground if the rock is big enough.

[Orion78]

Ok well, lets suppose for a minute that you're right and meteors don't cause craters when they hit. What happens to them after they enter the atmosphere?

[U S Army EOD]

How do we know you are not an alien who keeps getting put on hold every time you try to phone home.

[PatrickHenry]

What happens to them after they enter the atmosphere?

You mean if rocks really do fall from the sky and enter the atmosphere? Too many hypotheticals in that question. First, show me that the sky is full of rocks. Then I'll deal with what's left of your question.

[Orion78]

Just curious, was does EOD stand for?

[U S Army EOD]

Normally they burn up, but some times they make a big hole in the ground. On other rare occasions they penetrate the top of automobile and certain young ladies feet. There is in fact a woman in one of the New England states you had the unique misfortune of actually being hit by a small one. This is documented.