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RE: Theories on the extinction of dinosaurs




> << Yep.  This is why the impact is included as *one* of the causes in all
>  multicausal models. >>
> 
> Multicausal extinction theories suffer from the problem of having all the 
> causes come together simultaneously 
< I think by definition, this is multicausal! >
> all over the world to produce the 
> extinction. As the number of causes goes up, the probability of this 
> happening drops >way< down. On the other hand, even the asteroid impact 
> theory is a multicausal theory, in the sense that something else going on
> in 
> the world must have made the dinosaurs particularly vulnerable to an 
> asteroid-impact extinction at the time that the impact happened.
< I believe, thought it is messy, that a multicausal theme must be embraced
as to the mass KT extinction as no one theory on it's own is enough to "do
in" the large percentage of creatures that disappear ofter the KT impact
layer. We know the Deccan Traps were spewing forth their magma at least a
million years before the impact. This might have poisoned the atmosphere,
weakened the ecology of the dinos, and along comes the impact as a sort of
final coup-de-gras the did for the Mesozoic fauna. >
>  After all, 
> there were other impacts in dinosaur history that did not have the 
> devastating effect of the K-T impact (though they may have been
> responsible 
> for some of the abrupt changes seen in the dinosaur fossil record).
>