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Re: Extinction

tholtz writes:
>You (and many others, of course) are guilty of conflating two arguments -
>the date of the K-T impact, and the date of Chicxulub.  The Late Cretaceous
>was a LONG period of time, but many people not trained in stratigraphy have
>automatically assumed any Late K impact is a TERMINAL K impact.

>Now, I personally think that Chixculub is a, if not the, terminal K impact.
>However, Meyerhoff et al. have presented data showing sedimentary rocks of
>middle Campanian through Maastrichitan (and up into the Paleogene)
>*overlying* the disturbed layer.  If true, than Chixculub occured 8 or 10
>million years prior to the K-T boundary, and so could not be the causal

>Now, of course, if the dating is correct, that suggests there was a
>seperate, terminal K impact elsewhere.  Additionally, there is the
>possiblity that the overlying rocks were slumped into the crater
>post-impact.  Nevertheless, these possibilities should be examined, not
>assumed (just because they favor a cherished hypothesis).

>To sum up - the impact theory looks good for the terminal K extinctions,
>and (somewhat less so) the impact site appears to be Chixculub.  However,
>these are two seperate arguments, and each must be examined independantly.

Sir, you seem to have missed my point entirely.  I am suggesting that the
date of the Chixculub impact can be dated directly from the fossil record at
any place on the globe.  An impact creating a 120 mile crater would devastate
life everywhere on earth, and if it were to occur 8 million years prior to
the KT boundary, as you pose as a possibility, a mass extinction would have
occurred there, but as you probably know T rex and others not only flourished
during this time period but actually evolved. 

Futhermore, I do not claim that the Mexican impact was the sole impact -- I
expect the object fragmented from tidal forces in a fashion similar to the
recent comet strike of Jupiter -- but I do believe, as I feel is obvious,
that the object that generated the Chixculub crater and any sister impacts
exterminated the dinosaurs.