Chixulub and K/T boundary

["Stupendous Man" <richmond@astro.Princeton.EDU>]

  Thomas R. Holtz, in a very informative letter, said:

> The evidence for a gigantic impact at the K-T boundary is very secure,
> although some impacts previously attributed to the boundary are not the
> correct age (e.g., the Manson Crater is demonstrably too old by ~12 million
> years!).

> This crater coincides (so far as we can tell with the admitedly-patchy
> fossil record) the extinction of the latest Maastrichtian dinosaurian
> faunas ...

  I have been told that papers "soon to be released" will claim
that a close examination of some of the sediments from drillholes
into the Chixulub crater area shows Cretaceous marine layers
_on top of_ the impact breccia.  I guess that the layers are dated
by forams.

  I'm aware that radioisotope studies have shown that Chixulub
occurred very close the the accepted K/T age, but, if true, this
new result would punch some holes in the impact-extinction 
theory.

  Can anyone provide further details of the sediment studies?
If not, we'll have to wait for the papers to appear, I guess --
I was told to watch geological journals, not Nature/Science...

                   Michael