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Espritch
Skeptic Friend
USA
284 Posts |
 Posted - 07/08/2001 : 12:58:47
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I came across the following web site a while back and would like to find out what the rest of you think about it.
http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/
The site discusses a volcanism based theory of dinosaur extinction purposed by Dewey McLean. The theory as described seems to make sense.
What concerns me more is that he also asserts that physicist Luis Alvarez with the complicity of evolution scientists David Raup and Stephen J. Gould essentially tried to destroy his career because Alvarez didn''t like him purposing an alternative to his own Impact theory of dinosaur extinction.
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Bozola
Skeptic Friend
USA
166 Posts |
 Posted - 07/08/2001 : 13:40:07 [Permalink]
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There is still doubt that the KT asteroid was the catastrophic killer as envisioned by Alverez, etal.
There is no firm timeline of the extinction. The KT asteroid theory requires a very rapid extinction, but there seems to be data that does not agree with this. This could be an artifact of not having enough data to map the strata in question fully enough. It cannot be presumed that the creatures who became extinct in the Maastrichtian did so at the same time, and the same rate.
The extinction event was planetary in scope; it appeared to affect all terrestrial and aquatic ecosystems to some extent.
There are less than one thousand skeletons (or partial skeletons) from the last ten million years of the Cretaceous. This truely marginal data which to derive trends of population and diversity from.
There is strong evidence of a bolide strike near the end of the Cretaceous.
There is strong evidence of major vulcanism near the end of the Cretaceous.
There is no evidence for biotic replacement occuring; i.e. dinosaurian herbivores being gradually replaced with mammilians ones, for example.
All non-avian dinosaurians died out at the end of the Cretaceous; the evidence suggests that all land vertibrates exceeding 25 kg went extinct.
One hell of a puzzle.
Bozola
- Practicing skeet for the Rapture.
Edited by - Bozola on 07/08/2001 13:42:00 |
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Lars_H
SFN Regular
Germany
630 Posts |
Posted - 07/08/2001 : 13:48:02 [Permalink]
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I do not have the scientific expertise to asses his theory, but I tend to be careful whenever somebody cries CONSPIRACY. There are a number of proposed explanations for the extinction of the dinos. The Volcano and the asteroid are just two of them. None of the (serious) other theories feel that they were conspired against.
Even if somebody worked to have McLean silenced There several new theories or new variations proposed every year, some of them less likely then his. You have to feel that if there was something to it somebody else would have taken it up.
It may be the writeup and not the theory itself, but it seems to lack some of the things that would make a theory more believable to me:
- references there are number of refernces in the text, but non of them are directly supporting his theory.
- open questions The whole thing seems a bit to perfect. Every theorie has at least on or two open questions or arguments that could be used against it. And a good scientist is aware of those parts that could be improved and includes them so others can improve on his ideas. This just seems to good to be true.
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Boron10
Religion Moderator
USA
1266 Posts |
Posted - 07/08/2001 : 13:50:40 [Permalink]
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quote:
What concerns me more is that he also asserts that physicist Luis Alvarez with the complicity of evolution scientists David Raup and Stephen J. Gould essentially tried to destroy his career because Alvarez didn''t like him purposing an alternative to his own Impact theory of dinosaur extinction.
I have no way to test the validity of this, but I know the scientific community can be very treacherous. If this is true, it would not be the first time something like that happened.
-Timmy! |
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ljbrs
SFN Regular
USA
842 Posts |
Posted - 07/08/2001 : 19:11:16 [Permalink]
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Theories always are in question in science. They are always open to review. There is a lot of evidence for the KT theory. The KT theory is far from having been discredited. Also, it necessarily would have taken a long time for the global extinction. Since it was planet-wide, it could not have been a short-term extinction except in the vicinity of the KT site itself.
As for the volcano theory, I will let the experts fight it out. If it turns out to be correct, it will win out in the long run (as did Alfred L. Wegener with his Plate Tectonics theory, although, sadly, it was confirmed after his death). I have full faith with peer review. In the long term, it works very well. In the short term, fur can fly.
I will bet on the KT or some other development of that theory. For the volcano theory, there needs to be geological evidence, similar to the KT theory's evidence (which has grown since the theory came out).
I will let the scientists fight this one out. Unless any of us are experts in this field, this is about all that we can do.
ljbrs
Perfection Is a State of Growth...
Edited by - ljbrs on 07/09/2001 21:25:37 |
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bestonnet_00
Skeptic Friend
Australia
358 Posts |
Posted - 07/09/2001 : 02:28:06 [Permalink]
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There is another possibility, but I would suggest against taking it seriuosly.
Radioactive GM Crops.
Slightly above background.
Safe to eat.
But no activist would dare rip it out.
As they think it gives them cancer. |
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ljbrs
SFN Regular
USA
842 Posts |
Posted - 07/09/2001 : 21:28:47 [Permalink]
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bestonnet_00:
My ancestors will vouch for that!
ljbrs
Perfection Is a State of Growth... |
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Espritch
Skeptic Friend
USA
284 Posts |
Posted - 07/13/2001 : 22:56:44 [Permalink]
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quote:
My ancestors will vouch for that!
OK. I'll bite. So what happened to your ancestors?
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