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Science

Volcanoes May Have Caused Mass Extinctions? 210

Posted by Zonk from the can't-breath-must-snack-on-mammals dept.
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."
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Volcanoes May Have Caused Mass Extinctions? More

Volcanoes May Have Caused Mass Extinctions?

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  • The Chicxulub impact alone could not have caused the mass extinction, because this impact predates the mass extinction.

    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?

    • Doh... (Score:3, Informative)

      by Anonymous Coward
      How's it going to cause a mass extinction if it takes place after the mass extinction occurs?


      If you had ate least read the summary, you would have realized that this "predate" here means 300000 years...

    • Re:Pre hoc ergo propter hoc? (Score:5, Informative)

      by SnowNinja ( 1051628 ) on Friday November 02, 2007 @04:05PM (#21216737)

      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.
      • >>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.

        I would Love to know the margin of error radioactive carbon dating has at a 65 million year old site, where other radioactive elements were deposited.

      • Re: (Score:2)

        by Miraba ( 846588 )
        Apparently there's some controversy as to whether the gap is a result of normal geological activity or a direct result of the impact. See the last paragraph of this section [wikipedia.org].

    • Re:Pre hoc ergo propter hoc? (Score:5, Interesting)

      by IdleTime ( 561841 ) on Friday November 02, 2007 @04:15PM (#21216891) Journal
      Gerta Keller... *sigh*

      I think everyone should take her research with quite a few grains of salt, she has been in a bitter fight for years over this issue and she has been quite obnoxious when it comes to the topic of Chicxulub and mass extinction. Until this is confirmed by independent research, nobody should take it for gold.

    • 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?

      Geologic timescales. Here, 'predated' implies 'predated significantly enough such as to be unrelated.' This is understood by everyone who isn't trying to be as pedantic as humanly possible.

    • Re: (Score:3, Interesting)

      by Black Copter Control ( 464012 )
      It's like you shoot your friend in the back tonight, and (s)he dies in 2010. It's not that your friend no longer died after you fired the gun, but rather the 2-3 year wait kinda cancels the 'smoking gun' effect.

      If, on the other hand, the prosecution produces evidence that you shot your friend in the head, and then your friend went into a coma for 2-3 years before dying, then they might still have good grounds for a murder charge.

      Such a coma effect might be if we could show that the 300,000 years of in

      • It's like you shoot your friend in the back tonight, and (s)he dies in 2010. It's not that your friend no longer died after you fired the gun, but rather the 2-3 year wait kinda cancels the 'smoking gun' effect.

        Actually, depending on where the person was shot in the back, the bullet could indeed kill them a number of years later.

        Likewise, it's not impossible that, even if she's right about the time difference (which is debatable as others have pointed out), the meteor strike could have set off a series of e
  • Obviously they've hunted land they can see, maybe look under the ice? Just recently greenland discovered a new island when some ice melted.
    • I think you'd have to go a long way down. I think Anywhere with ancient surface easily available would be OK. Mountains are more likely to be a good place, since deep ancient surfaces are uplifted.

      It's not so easy to find good sites though, Time is money, and there isn't much of either available usually. Most places where you can find good rock are out of the way, and many have only a few months of the year you can be there.

      • Re: (Score:2)

        by mrkitty ( 584915 )
        You'd think they'd be able to use some NASA technologies (xray, heat, whatever else they use to probe the cosmos) from space or something to see through the ice, then identify suspect patterns. Money for sure is an issue.

    • Re: (Score:2)

      by Burz ( 138833 )
      Funny you should mention that.

      I recall reading several years ago about a gigantic impact site located between Australia and Antarctica. I don't recall when it was supposed to have hit.

  • where's the crater? (Score:2, Funny)

    by Anonymous Coward
    But where's the crater? "I wish I knew

    Its gotta be in Oklahoma. Trust me, that place is a **** hole!

  • Xenu (Score:3, Funny)

    by jas_public ( 1049030 ) on Friday November 02, 2007 @03:59PM (#21216655) Journal
    This sounds like an L. Ron Hubbard story.
  • I know the circumstances of the dinosaur's extinction are controversial, but this is what they tought me way back in elementary school...

  • is it warm in here? (Score:5, Funny)

    by User 956 ( 568564 ) on Friday November 02, 2007 @04:04PM (#21216709) Homepage
    The Deccan volcanism was a long cumulative process that released vast amounts of greenhouse gases into the atmosphere.

    Yeah, but with our advanced technology, we can cut that time in half.

  • Easy (Score:3, Funny)

    by rucs_hack ( 784150 ) on Friday November 02, 2007 @04:06PM (#21216751)
    It shouldn't be that hard to work it out, after all, wasn't it only about ten thousand years ago it happened? /ducks :)

  • Ridiculous... (Score:5, Funny)

    by gentlemen_loser ( 817960 ) on Friday November 02, 2007 @04:09PM (#21216805) Homepage
    Everyone knows that the earth is only 6000 years old, as evidenced here [creationmuseum.org] They even have models of Eve with vegetarian Raptors. See. [arstechnica.com] I do not understand why anyone pays any attention to these activist scientists. Duh...
    • Vegatarian Raptors? Heh. Is that really an exhibit? I'd go see it, but I'd probably wet myself from laughing.

      What does a Raptor with six inch claws eat? Anything it wants.

    • Re: (Score:2)

      by Empiric ( 675968 )
      Well... not according to Jesus.

      When you see your likeness, you are pleased. But when you see your images which came into existence before you, which neither die nor become manifest, how much you will have to bear!

      --Gospel of Thomas

    • Re: (Score:2, Funny)

      by Digital Vomit ( 891734 )

      Ha ha ha! Oh gosh that's funny! That's really funny! Do you write your own material? Do you? Because that is so fresh. "Everyone knows that the earth is only 6000 years old". You know, I've never heard anyone make that joke before. Hmm. You're the first. I've never heard anyone reference that on Slashdot before. Because that's what the religious people say in church right? Isn't it? "The earth is only 6000 years old". And, and yet you've taken that and used it out of context to insult people who are differe

      • there's something deeply ironic about some dude taking another dude to task over his use of an overused worn-out dig by dragging out an overused, worn-out insult.

        i like the family guy bit. or well, i liked it the first 50 times somebody cribbed it.

      • Re:Ridiculous... (Score:4, Funny)

        by lgw ( 121541 ) on Friday November 02, 2007 @06:48PM (#21218797) Journal
        Wait, wait, let me get this right. The "6000 years" thing is so obviously stupid that no one should accuse Christians of believing it, but the part where Christians believe that a cosmic Jewish zombie who was his own father can make you live forever if you symbolically eat his flesh and drink his blood and telepathically tell him you accept him as your master, so he can remove an evil force from your soul that is present in all humans because a woman made from a rib was convinced by a talking snake to eat from a magical tree and thereby pissing off an invisible wizard who lives in the sky -- that part -- is not obviously stupid at all, but obviously true?

        For simplicty, please list which fairy tales you do and don't believe in, so we can insult your *actual* beliefs?

  • Cause (Score:5, Interesting)

    by rossdee ( 243626 ) on Friday November 02, 2007 @04:12PM (#21216855)
    Maybe the meteor impact caused the volcanos to start up.

    • Re: (Score:3, Funny)

      by rucs_hack ( 784150 )
      There is a theory that this is what happened. The Siberian Traps were already going, they were a long term thing, but they had an upsurge of activity that was seriously bad for the environment at around the time the Asteroid hit, or so I recall, it was a while ago I learned this. Wait a bit and I'm sure a slashdotr technorati will provide the ref :)

    • Re: (Score:3, Informative)

      by Miraba ( 846588 )
      That's already been proposed. See the entry on the Shiva crater [wikipedia.org].

  • ...it must have been 7-8 degrees warmer..
    and a whole lot tighter, right?

    right?

  • Oblig futurama (Score:3, Funny)

    by Joe the Lesser ( 533425 ) on Friday November 02, 2007 @04:14PM (#21216867) Homepage Journal
    Fry: What killed off the dinosaurs?

    Giant Super Brain: Me!
  • How about a huge impact somewhere in the south Pacific west of Chili, this caused a shockwave rippling out from there around the world. The shockwave ripples then reconverged on the opposite side of the world in India, causing the Deccan Traps to go pop. I figured out the likely location using the wonderful Earth Sandwich tool http://www.zefrank.com/sandwich/tool.html [zefrank.com]
    • I figured out the likely location using the wonderful Earth Sandwich tool

      Nice try, but it must be wrong; Dad said we could dig a hole straight down to China, but that we shouldn't because all the commies would come pouring through.
  • A crater all that big would be pretty obvious, i.e. Hudson Bay or possibly the general Yucatan shape. I vote for the Yucatan because maybe it followed the other rock in right behind it and hit harder, which is why the one famous crater is so hard to see land-wise. Maybe the 300,000 years is how long the iridium took to land back on earth from being jettisoned into our atmosphere and/or beyond. (gravity)
    • I vote for the shallow sea in between India and Asia (now the Himalayas). It might also explain why India was traveling so fast when it hit Asia.

      • Re: (Score:2)

        by arivanov ( 12034 )
        Jokes aside search for "Shiva Crater". Just found it myself and it sounds like the crater you are looking for.

        • Re: (Score:2)

          by arivanov ( 12034 )
          Just read what I posted :-) "Found it" in the sense "found references about it on the net" :-)
  • But where's the crater? "I wish I knew," says Keller."
     
    It's the entire Gulf of Mexico. I mean, it's obvious from the shape of the thing.
     
    Remember you read it here first.
    • can I join your fan club? My first thought was "Under the antartic cap of course" but I think the gulf is the best cosmo-conspiracy theory yet. (an no I am not being sarcastic)
    • the gulf is two craters overlapping. try the sea of japan instead.

  • Comment removed (Score:4, Funny)

    by account_deleted ( 4530225 ) on Friday November 02, 2007 @04:24PM (#21217057)
    Comment removed based on user account deletion

    • Re: (Score:2)

      by ReTay ( 164994 )
      DUH! The Church of Scientology has been saying this for years now, people! Get with the times!
        (Score:-1, Troll)

      All right who gave mod points to a bivalve?
      (And yes I am sure everyone else would have found that funny.)
    • DUH! The Church of Scientology has been saying this for years now, people! Get with the times!
       
      Parent is FUNNY via witty sarcasm and reasonably on topic not TROLL.
       
      OK, not 5 but at least 2 or 3.
  • Massive-ass Earth Farts, and Ka-Phooey! That's all it took?
  • The idea that absolute dating techniques can survive catastrophic events without the introduction of abnormalities is rather presumptive. Just last week, there was an announcement that uranium isotopes are not invariant ...

    http://http//www.sciencedaily.com/releases/2007/10/071023103947.htm [http]

    What is the cause of the extraneous decay?

    One Russian researcher has performed a simple experiment that demonstrates a statistical enigma within decay rates that mysteriously correlates with movements of the stars, the Su

    • Re: (Score:2)

      by geekoid ( 135745 )
      The radiocarbon* techniques are very accurate. How accurate depends how far back they go. So when we are talking millions of year, you might have a 25,000 year deviation.

      *Important to note, the use different things for decay depending on the age of the product. Carbon dating with carbon 14 is useless for things over 50,000 years. That's about 9 half lives. So they use other elements with a longer half life.
      • You could have just as easily written "is not" and left it at that.

        The OP made a clear and convincing argument. Showed examples of people doing very non-scientific things like throwing out data that doesn't agree with them. That is just plain wrong.

        Science should be held to a higher standard. It should not kowtow to consensus or preconceived notions. What good is peer review when the reviewers are biased? What good is peer review when articles that challenge the consensus get rejected? It's about
      • The radiocarbon* techniques are very accurate.

        Just to be pedantic, radioisotope dating is precise (by your example), but may not be accurate. Precise indicates that you can get results with many significant figures (like +/-25,000 years out of 65 million). Accurate indicates that you can get results which are correct.

        It is possible to have precision without accuracy. The parent post was suggesting radiometric dating suffers from inaccuracy, you have claimed it does not suffer from imprecision. You

    • Re:Absolute Dating Absurdity (Score:4, Informative)

      by zerocool^ ( 112121 ) on Friday November 02, 2007 @05:12PM (#21217681) Homepage Journal

      For starters, the 21st Century Science and Technology [wikipedia.org] is NOT a reputable, peer-reviewed scientific journal. It is a group of quacks. Literally, the magazine (which is not even printed anymore, copies are available now as pdf only) is a thinktank of scientists who challenge "the assumptions of modern scientific dogma, including quantum mechanics, relativity theory, biological reductionism, and the formalization and separation of mathematics from physics." (from their statement of purpose).

      Furthermore, the "21st century" publication follows the line of groupthink known as the LaRouche Movement [wikipedia.org], a wacky pseudo-political group of conspiracy theorists and nutcases. Their group spews fascist, anti-semetic ideology like it's going out of style.

      That alone makes your bullshit transparent, but you state that you want something other than attacks on credentials (I happen to believe that scientists stand or fall on their credentials, including past bodies of work, but whatever). So, in a nutshell, Radiometric Dating [wikipedia.org], including Carbon-14 dating and other methods such as Rubidium-strontium dating and Uranium-lead dating, is EXTREMELY accurate and accepted by all reputable scientists and peer-reviewed scientific journals.

      So, if your russian scientist is the only one shouting that it's inaccurate, we must be left asking "Why does every other scientist accept it, and what is his axe to grind?".

      ~Wx
      • ... 21st Century Science and Technology is NOT a reputable, peer-reviewed scientific journal.

        I won't argue with your assessment. However, they didn't publish the research in question.

        The original article was published in Physics-Uspekhi (Advances in Physical Sciences) [turpion.org], which looks like a respectable journal. The English version of the Russian article is here [turpion.org]. The abstract doesn't say what 21st Century Sci-Tech says. The reviewer's comments are here [turpion.org].

        If anyone can get access to the full text, let u

      • Re: (Score:2)

        by pln2bz ( 449850 ) *
        The study is a Russian study. I think the proper response to ask whether or not people have actually attempted to replicate the experiment? And if not, why is that?

        My understanding is that some of the other quotes in there were from reputable scientists and from reputable peer review journals, btw. If you're going to appeal to credentials, then that should be a two-way street: if somebody *of* credentials says something, then it should be followed up on, right?
      • What is the error on these geological date estimates? They say in the article that there was a 300,000 year difference. Can they pin down events 65M yrs old to the nearest 100,000 years?

    • I'd love to hear *reasons* for why these people would be wrong (as opposed to attacks on their credentials). Why do we place so much confidence in dating techniques when there is apparently quite a bit of controversy about them, and in spite of demonstrations that there may be significant problems?

      The controversey and 'demonstrations' are mostly from people with an axe to grind - not people interested in the scientific process.

      Now, take this quote as prime example:

      In fact, the denouement ca

      • Re: (Score:2)

        by pln2bz ( 449850 ) *
        Wow. It's amazing that you accept the ambiguity of the dating technique as just a part of the scientific process. And you call Ginenthal a pseudoscientist?

        • Re: (Score:2)

          by samkass ( 174571 )
          It's amazing that you accept the ambiguity of the dating technique as just a part of the scientific process. And you call Ginenthal a pseudoscientist?

          Ambiguity *is* part of the scientific process. Only a pseudoscientist is certain enough to say otherwise.

          • Re: (Score:2)

            by pln2bz ( 449850 ) *

            Ambiguity *is* part of the scientific process. Only a pseudoscientist is certain enough to say otherwise.

            Yeah, but your methodology is ambiguous enough to allow for whatever results the peer review journals will permit. How can you possibly fault me for being skeptical of that? I would go so far as to say that anybody who did not exhibit a healthy dose of skepticism towards those results were faking their own skepticism of anybody who doubted them.

            I realize that you probably invested a chunk of change and

    • I am very wary of your argument style. It is heavy on quotes but not much on the measurements themselves. This is very reminiscent of my past arguments with Creationists before I saw the light and realised they were a bunch of losers not deserving of my time.

      I will follow my personally approved style on these issues: take the first article and look at it carefully, if it fails .... do not proceed.

      Yes the article talks about measurements that indicate a separation of U235 and U238 isotopes therefore skewin

      • Re: (Score:2)

        by pln2bz ( 449850 ) *

        Yes the article talks about measurements that indicate a separation of U235 and U238 isotopes therefore skewing age determination using this mechanism. However, this is only in sandstone. It is believed to be due to either water action or microbes. This does not affect igneous rocks. Therefore if the researcher is careful about the environment of the sample and the rock type and backs it up with other methods they should be OK. In fact the oldest rocks are dated using not just any bit of dirt they find but

    • http://redshift.vif.com/JournalFiles/V09NO2PDF/V09N2BRU.pdf [vif.com] contains an analysis of the analysis (yes, you read that right) of an experiment on tritium, which experiment was apparently inspired by Shnoll's. Interestingly, the analysis was published in a journal (Apeiron) which is known for being of a more -- ahem -- speculative journal than many mainstream scientists are comfortable with.
      The analysis (as spare of details as it is, I admit) is not favorably impressed with the or

    • Re: (Score:2)

      by barakn ( 641218 )

      What is the cause of the extraneous decay?

      The article you referenced (with a flawed URL) did not mention extraneous decay. The authors merely stated that the ratios of isotopes varied more than expected depending on the original method of deposition. This partitioning of isotopes has absolutely nothing to do with decay and does not support your argument.

      One Russian researcher has performed a simple experiment that demonstrates a statistical enigma within decay rates that mysteriously correlates with movem

      • Re: (Score:2)

        by pln2bz ( 449850 ) *

        Also, cosmic ray rates are well-known to have diurnal and annual cycles and I haven't seen any evidence that the Russian biologist knew enough about this to adequately shield his experiments from them.

        I think this goes to the heart of the matter, actually. The uniformitarian assumption that the number and intensity of incoming particles (like cosmic rays) never changes flies directly in the face of the notion of a catastrophic event. What happens in a catastrophic event? We really don't know. But, what

  • I caused the mass extinction (Score:5, Informative)

    by tjstork ( 137384 ) <todd.bandrowsky@ ... UGARom minus cat> on Friday November 02, 2007 @04:34PM (#21217177) Homepage Journal
    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!
  • They say that meteor hit 300,000 years before the KT extinction. That would mean that they are able to date the rocks in the KT layer and samples from the crater to within 0.4% error (300,000/65,000,000). I don't know of any radioactive dating techniques that are used to date in the 10's million of years. Even with those, the accuracy will vary from researcher to researcher and sample to sample. If they are analyzing the the thickness of sediment layers on the side of a cliff, I can't see how they could cla
  • Assume a volcano somehow got plugged up & couldn't errupt normally.
    Could an exploding volcano look like a meteorite crater ?

    What if a metorite crashed into the other side of the earth as exists a volcano, could a big enough impact cause a shockwave & an erruption on the other side of the planet much larger than normal erruptions ?
    • There are some craters that are so big and so old that no-one knows whether it was an impact or an explosion. For example, the Bushveld Complex in South Africa is about 500km in diameter and no-one knows how it formed. The famous gold mines are around the rim of that crater. It is so big and so old, that there are other, smaller and more recent impact craters inside it.
  • there's a saying medicine when looking to diagnose medical symptoms: when you hear hoofbeats, don't think of zebras (it's more likely to be horses causing the noise)

    it's a variation on occam's razor: the more exotic explanation is the less likely one

    volcanic activity is more likely than asteroids
  • OK, maybe/not really.
    I was just looking at google maps one time an it sure looks like the remnants of a crater to me, judge for yourself.
    The visible arc of the eastern most portion of the crater is the coastline to the east and a bit north of Polar Bear Provincial Park.
    Why else would you have such a large semicircle coast just cut out of an otherwise irregular coastline?
    http://maps.google.com/maps?ie=UTF8&ll=56.583692,-79.672852&spn=10.630137,27.597656&z=6&om=1 [google.com]

    • Re: (Score:2, Interesting)

      by securityfolk ( 906041 )
      I dunno - between 20W and 80W, and 55S to 65S (to the West of the Sandwich Islands), there are some bizarre ocean bed shapes (check http://maps.google.com/maps?ll=-59.739775,-46.557183&z=4&t=h&hl=en [google.com]). Looks like something - or maybe a couple of somethings smacked into Earth pretty hard. Looks like it hit hard enough to separate Antarctica from South America, or at least severely deform the mantle around that area. Does anyone have the scoop on what caused that region?

    • Re: (Score:2, Interesting)

      by onion_joe ( 625886 )
      Hmmm, that one is pretty interesting, especially the semi-circular concentric ridges in the bay.

      However (of course, sorry) this http://maps.google.com/maps?ie=UTF8&ll=56.583692,-79.672852&spn=10.630137,27.597656&z=6&om=1 [google.com] also looks kinda funny, and there is no evidence of an impact site. Current theory is a standing wave pattern related to ocean currents and tides. No shocked quartz, no tektites. Bummer, because that is in my neck of the woods and I am a geo-nerd.

      Only way to find out

  • 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."

    Iceland. I watched a documentary on this in the early 90's. The iridium concentration grows as you get closer to Iceland. Iceland is a volcanic island that is the result of a large extraterrestrial object shattering the thin crust on a mid-ocean ridge. It formed a rather large volcano that brought up a lot of material for millions of years, and is still somewhat active even today (Iceland). Iceland is also somewhere between 60 and 70 million years old, which is when the object impacted.

  • I thought there was still some debate regarding whether the Central American crater is the actual impact site of the dinosaur-killing asteroid?
  • There are other, larger impact craters on earth, so the Mexican crater idea was improbable all along. The earth's atmosphere is produced by outgassing of the planet through volcanoes and vents, so this is obviously a major reason for atmospheric change.
  • I hate to be a bit self referential, but when Dr Keller came out with her press release, I wrote up a comparison of the Permian-Triassic and the Cretaceous-Tertiary Extinctions [blogspot.com]. The whole article centers around the idea that the Permian Extinction is assumed to be one caused by vulcanism where there is VERY strong evidence for that being the root cause so we ought to compare the KT to the PT if we want to see if lava trumps meteor.

  • So (Score:2)

    by Dunbal ( 464142 )
    But where's the crater? "I wish I knew," says Keller."

    And no one but me has ever noticed the round, almost crater-like shape of the Gulf of Mexico...?
  • I have seen loads of pictures of dinosaurs and there is often a volcano erupting in the background. The dinosaurs couldn't care less.

  • Keller's far-out (Score:3, Informative)

    by yusing ( 216625 ) on Friday November 02, 2007 @10:08PM (#21220565) Journal
    The 300,000 year hypothesis isn't widely supported.

    "Many scientists reject Keller's analysis, some arguing that the 10 meter (32.8 ft) layer on top of the impact spherules should be attributed to tsunami activity resulting from impact. Few researchers support Keller's dating of the impact crater." -- Wikipedia ... http://en.wikipedia.org/wiki/K [wikipedia.org]-T_boundary
  • Under the Deccan traps?
  • Let's get real about this. We all know what really killed the dinosaurs: High insurance rates!

    Paul Robinson - My Blog [paul-robinson.us]

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