K-T strike

[Hellcreek@aol.com]

H there:

I read that Science paper concerning the chromium isotopic evidence for mass
extinctions.  The authors mention that their analytical method for measuring
the isotopes relies on mass spectrometic  (MS) detection.  However, as is
mentioned in a footnote, the details of the procedure will appear in another
paper.  (I presume the method is Inductively coupled plasma (ICP)-MS
permitting the very low detection limits.)

To me, this is represents one of the best (and most interesting) cases I have
read concerning chemical evidence in support of impact since the first
published studies of K-T iridium in 1980.  Hopefully the authors will apply
this approach to other extinction boundaries as well.  And while this new
information does not settle the argument as to whether dinosaurs became
extinct in consequence of the impact, I  favor the impact-caused extinction
scenario(s).

Allen A. Debus