Re: Atmosphere at K-T extinctions

["James R. Cunningham" <jrccea@bellsouth.net>]

Seosamh wrote:

> If oxygen concentration went up, something(s)
> else decreased.

No, CO2 was at about 5 times present levels, and nitrogen was unchanged.  
Nothing else
was or is present in high enough quantities to be meaningful.  No decrease in 
other
gases just means atmospheric density was up too, though the increased 
temperatures may
have acted to increase the density altitude and offset the effect somewhat.  As 
an
aside, I looked density altitude when I started working on Quetzalcoatlus flight
mechanics, and decided the data was too iffy to bother using anything other 
than our
present atmosphere. I just do my calculations using indicated airspeed rather 
than true
airspeed.  The difference in atmospheric density wasn't really enough to affect
flightworthiness anyway.  Anything that could have flown then, could fly now.