Volcanoes May Have Caused Mass Extinctions?

Hugh Pickens writes "According to recent research, huge amounts of sulphur dioxide released by volcanic eruptions may have had more to do with wiping out dinosaurs than the meteorite strike at Chicxulub on Mexico's Yucatán Peninsula. Marine sediments drilled from the Chicxulub crater have revealed that that the mass extinctions occurred 300,000 years after Chicxulub hit Earth. The Deccan volcanism was a long cumulative process that released vast amounts of greenhouse gases into the atmosphere. '"On land it must have been 7-8 degrees warmer," says Princeton University paleontologist Gerta Keller. "The Chicxulub impact alone could not have caused the mass extinction, because this impact predates the mass extinction."' Keller also postulates a second larger and still unidentified meteor strike after Chicxulub, that left the famous extraterrestrial layer of iridium found in rocks worldwide and pushed earth's ecosystem over the brink. But where's the crater? "I wish I knew," says Keller."

Comments

Re:Pre hoc ergo propter hoc?

[SnowNinja]

For the Chicxulub impact to have caused the mass extinction, it *must* have predated the mass extinction. How's it going to cause a mass extinction if it takes place after the mass extinction occurs?

I think what they're trying to say is that 300,000 years is a little long to actually attribute the mass extinction to the meteor. If it were the direct cause, the extinctions would have occured in a much more narrow time frame.

Re:Pre hoc ergo propter hoc?

[ByOhTek]

Given that radiocarbon dating looses too much accuracy to be useful somewhere between 5k and 10k years... I seriously doubt they used that. Especially since it wasn't mentioned in the article.

Some quick (20 second) searching found some things you might like to enlighten yourself with.
Radometric dating, methods other than just carbon
They probably used thermoluminescence dating.

I caused the mass extinction

[tjstork]

I do not care much for lizards. They are big, stupid and slow, and they smell. All these dinosaurs are around, and I hated them all, but there's all sorts of stupid regulations about dinosaurs, thanks to Al Gore leading the save the dinosaur charge.

So I hopped into my time machine, gathered up some of the world's famous hunters, went back in time and killed the dinosaurs. Me and Buffalo Bill must have slaughtered 1,200 T-Rex's in what is now Montana, just in one night of drinking and hooting and hollering and a-shooting.

Those of you wonder what really happened to Jesse James, though, should know that he really did die 65 million years ago. We were playing cards one night after a big hunt and I drew a royal flush to his full house. Jesse probably wouldn't blown my head off in anger, but Buffalo Bill was quicker on the draw and he said, "Don't even do it Jesse." Jesse stuffed his revolver back into his holster, grabbed the bottle and went off in a huff. But as he was a stompin' away, he was set on by a pack of raptors and chewed up. It was a sad thing, but T.R. was able to go shoot two down with that pistol of his, and, thus, while we couldn't save Jesse, we at least saved the bottle of whiskey.

I reckon it took us a few months to kill all them dinosaurs. Since they all ate the biggest dinosaurs, we just took out all the brontos and crushed their eggs, and the rest all starved. We shot a bunch too. And then I dropped everyone back into their own times, and came back to this one, and there was not a dinosaur to be found.

Thank god!

So I called upon Mr. Gore to see if he remembered how much he liked dinosaurs in this adjusted timeline, and he said that he thought dinosaurs were ok in their own time, and said that, if we didn't do something about global warming, dinosaurs might come back.

So now, I gotta back in time and gather up the boys and go visit henry ford.

Ah, the work that we do!