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Re: Theories on the extinction of dinosaurs



I agree, but Alverez' was not the only estimate.  I don't put a lot of
weight in any of the crater diameter estimates -- they vary too much, and
understandably so.

Norton, Patrick wrote:

> >> How do they know the object was 6 mi in diameter?<<
>
> > They don't, but estimate it from the size of the crater.<
>
> Actually, Alvarez et al estimated the size of the bolide in their 1980
> article, long before the Chixulub crater was found.  As I recall, their
> estimate was based on how large the object needed to be to result in
> global deposition of iridium in the amounts they found in their samples
> of the boundary clays.
>
> Pat