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Re: SVP press coverage



On Thu, 25 Nov 2004 21:01:30 -0500 (EST), John Bois <jbois@umd5.umd.edu> wrote:
> 
> 
> Right.  Did she address this, I wonder?  One would think you could model
> it.  Doesn't she argue that the manner of deposition is indicative of low
> energy conditions?  I wonder if she has refined this argument?
> 

Here is the website of Keller and team's findings:

http://geoweb.princeton.edu/people/faculty/keller/chicxulub.html

And she does indeed argue that the manner of dep.=low energy
environments at Chicxulub (although I have not read her older stuff so
I don't know how it compares :)

>From the conclusions section:
<blockquote> a) Yaxcopoil-1 contains a 50 cm thick laminated micritic
limestone between the impact breccia and the KT boundary. This
interval contains five thin green layers of glauconite formation with
each interval bioturbated. This indicates deposition occurred in
variable, but generally low energy environments interrupted by long
pauses of little or no deposition and glauconite formation.

b) There are no grain-size grading (except for dolomite rhombs that
may give that impression), no cross-bedding, no flaser bedding, no
sand grains in insoluble residues, that would indicate high energy
deposition due to backwash and crater infill. Though such evidence is
present in the top 15 m of the impact breccia.
</blockquote>

-Heather Yager