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Re: Theories on the extinction of dinosaurs



In a message dated 11/19/99 10:41:24 PM EST, sarima@ix.netcom.com writes:

<< Because this is the most widely accepted form of the hypothesis, I prefer
 to term any model in which the impact is only the final of a series of
 causes as a multicausal model.  This makes for less confusion, as it avoids
 the tendency to see an implication that the impact itself was fully 
sufficient. >>

The impact by itself >was< fully sufficient. That is >proved< for all 
practical purposes by the coincidence of the K-T boundary clay with the 
observed demise of the dinosaurs (speaking of which, the same issue of 
Science that has the Sereno et al sauropod article also has a feature [p. 
1281] on the extinction and the incidence of dinosaur fossils below and above 
the clay: at a mere 1.8 meters below the clay is the last known dinosaur, 
represented by a Triceratops bone; above the clay, zilch dinosaurian--the 
workers found >no< gradual extinction). The question of >why< it happened to 
be fully sufficient at that time is a different question peripherally related 
to the extinction. Maybe the dinos were weakened (whatever that means), maybe 
the impactor hit an especially noxious rock stratum, maybe this, maybe that, 
and maybe some more. Don't see any way to resolve such questions without a 
time machine.