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Re: New Paper about Selectivity of Cretaceous-Paleogene Extinctions



On Sun, Mar 14th, 2010 at 12:57 PM, Paul Heinrich <oxytropidoceras@cox.net> 
wrote:

> Dear Friends,
> 
> There is a new paper that proposes an interesting and novel
> idea about the selectivity of the Cretaceous-Paleogene
> Extinctions. It is:
> 
> Kikuchi, R., and M. Vanneste, 2010, A theoretical
> exercise in the modeling of ground-level ozone resulting
> from the K?T asteroid impact: Its possible link with the
> extinction selectivity of terrestrial vertebrates.
> Palaeogeography, Palaeoclimatology, Palaeoecology.
> vol. 288, no. 1-4, pp.14?23.
> 
> http://dx.doi.org/10.1016/j.palaeo.2010.01.027

Would ground-level O3 concentrations have been just as high in mountainous 
areas? It's hard to 
believe that no non-avian dinosaurs lived at any decent altitude. 

That's all assuming that the atomic mass of O3 was great enough for it to 
settle downwards 
towards sea level. CO2 concentrations apparently vary with altitude during 
colder months, but are 
relatively uniform during the warmer months.
http://adsabs.harvard.edu/abs/2002AGUFM.A62B0151W

If there was a period of rapid cooling following the K-Pg impact, then you 
might expect ground-
level O3 concentrations to be significantly greater at sea level than at 
altitude. Of course, that 
same cooling may well have forced mountain-dwellers downwards towards the 
potentially greater 
ground level O3 concentrations at lower altitudes.

I may have just answered my own question. :-)

-- 
_____________________________________________________________

Dann Pigdon
GIS Specialist                         Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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