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Re: Asteroid impact finally confirmed?



Stan Friesen writes;

>Because, even in the most sedimentation intensive environments
>a few decades, or even a century or two, is, at most, a very thin
>layer of sediment.  Even under optimal conditions, resolution to
>within a century is virtually impossible.

Under continuous sedimentation models, this is certainly the case.  However,
during unusual events (i.e. storms), a great deal of sediment can be deposited
in a relatively short amount of time.  My sed/strat professor once said,
"Estimating deposition in sedimentary rocks is dicey at best; a river can
deposit an inch of sediment in one century, while a hurricane can deposit
several feet of material in one day."  Even though geologists prefer to stay
with unaformatarianism models, staying strictly with those models could deliver
misleading results.  What needs to be determined is whether the z-coal layer
shows evidence of slow deposition or fast deposition.  Does such evidence exist?

>In short, a century *is* simultaneous as far as the fossil record
>is concerned.

Yes, but under the conditions where the unaformatarianism model works.


Rob Meyerson
Orphan Vertebrate Paleontologist

***
When the going gets wierd, the wierd turn pro."