Re: K/T impact (was Re: [for some reason] Tim's theory)

[John Bois <jbois@umd5.umd.edu>]

On Tue, 15 May 2001, Tim Williams wrote:

> Only a trickle of avian diversity (and disparity) survivied the K/T 
> boundary, in the form of the neornithines.

Since there is _no record_ of the extinction of enantiornithines, this
statement cannot be made.

> Certain mammals were hit hard (at least the marsupials).  As for them "going 
> up in smoke", see below.

Marsupial extinctions are also consistent with placental replacement
hypothesis.  How to choose between the two?

> The extinctions percolated from the bottom of the food chains upward.  The 
> devastating effect that prolonged darkness and cold conditions (perhaps 
> followed by elevated Greenhouse-like temperatures, as the ash and dust 
> settled but the CO2 stayed up in the atmosphere) would have on life 
> everywhere cannot be overstated.

Hypotheses should not be confused with facts.