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Re: Extinction scenarios




TomHopp@aol.com wrote:

> Regarding a white hot atmospheric pressure wave sweeping around the world as a
> result of the Chixulub impact, Brian (franczak@ntplx.net) wrote:
> <While I would certainly not deign to argue the physics described above,
> I do have to ask (as Peter Buchholz already has), how did *anything*
> survive this doomsday scenario you've postulated? Seems to me that this
> level of catastrophe would pretty much wipe the Earth clean of *all*
> life, no?>

No.  Once you get out a thousand miles or so, atmospheric mixing wouldn't be
complete, the peak pressure would be diminishing rapidly, and there would be a
number of survival windows.

>     Yeah, white heat in the air would be deadly, and if it swept ALL the way
> around the Earth it would pretty much cancel all animal life above ground.
> However, if the pressure wave petered out just short of 180 degrees, there
> could have been one last little spot left unscathed.

180 degrees opposite is one place I wouldn't want to be.  But I think you'd 
find a
number of shielded sites that wouldn't be too heavily impacted (in all the
requisite senses).

>  Interesting to ponder
> where such a refugium might have been, and who it existed for.
>     I imagine a population of far-flying neornithine birds overwintering in
> the Cretaceous Kerguelen Islands, deluged by rain, then experiencing the
> remnant of the pulse of atmospheric pressure as an uncomfortably hot and loud
> burst of excitement in an otherwise cold and dreary existence.  Later, these
> birdies would repopulate the rest of the enantiornithine-less planet in their
> far-flung journeys.
>     Also bear in mind that a quick pulse of white hot air might have
> relatively little effect beneath the surface of bodies of water, in pond mud,
> in caves, in burrows, etc.  This might explain turtle and frog survival,
> amongst others.

This sounds good to me.

>     Plants, of course, had long before learned to live with fire, and to
> resprout after catastrophes.

Yup again.Jim

>     Tom Hopp