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Re: extinction

"Dewey M. McLean" <dmclean@vt.edu> writes:

> Phil, for your:

> > "Your list [of sites with multiple Ir layers] is not sufficiently
informative.  What 
> > are 
> > the depositional environments at each of these sites? More 
> > importantly, what is the
> > *micro*-stratigraphy of these zones?,"

>  I simply do not have the time 
> to abstract this information for you.

No need to.  I have read these papers.  My question to you was
rhetorical, and it was meant as a specific challenge to you.  So far in
our dialogs, you have avoided discussing the possibility that the
stratigraphy at these multiple layer sites could have been altered by
slumping, overturning, or by other forms of redeposition (thereby
creating multiple Ir layers out of one event).  Since you say you have no
time to answer my question, then we'll just let the issue die.
As you know, I have my own informed opinion about these specific sites. 
I believe that a single iridium "event" was probably redeposited into
multiple iridium layers.

> Certainly, you will want to study the data base, methodology, and 
> conclusions drawn from each study. You can do that only by actually 
> reading each individual paper.

As I noted, I have read these papers.  For the sake of our present
discussion, it makes no difference to me what the opinions of the various
authors were.   They make their respective cases clear.  I was asking for
your opinion, since you seem to believe that multiple iridium layers
*always* means multiple iridium events.  If I have mischaracterized your
views, then it would be helpful for you to tell us which of the K-T sites
that you listed may contain redeposited iridium.



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