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Re: K-T impact theory

Dictator-for-life Calvin wrote:
> No matter how big the dead zone, "brief" is a relative thing in
> geological time.  Even if it took 100,000 years for North American
> ecosystems to recover (if you can use "recover" in terms of mass
> extinction), there's no guarantee that it would be represented in the
> fossil record.

I don't think you understand the full scope of my question.  Nuees
ardente wipe the ground clean.  _Everything_ is gone.  Trees get
charcoaled on the spot.  Brush is simply vaporized.  Animals are broiled
alive.  Seeds are either killed by the heat or buried too deeply to
germinate.  Nothing larger than a gopher survived the Mount St. Helens
ashblast, and those few animals that did survive the blast all died
within a couple of years because of lack of food.  Are you seriously
suggesting that life could recover from a disaster of far greater
magnitude across all of North America in a few thousand years?  
> >In short, if the impact was as devastating as is claimed, then how did
> >*anything* survive?
> What, impact theory is out because it's *too* effective an
> explanation?  

Exactly.  An impact of the sort currently fantasized would eliminate
_everything_, all macroscopic life.  The record shows that not
everything was eliminated.  An "asteroid winter" of the sort currently
imagined would have killed every photosynthesizing cell on the planet,
as well as forcing the temperature so low that endothermic mammals would
rapidly die of starvation (look it up, no shrew can go a week without
eating, and the asteroid scenario requires them to go years without
sufficient food).  Plants can't grow without soil.  Soil requires an
organic component.  A blast of the described magnitude should have
eliminated every scrap of organic material in the direct blast region. 
In fact, when you consider the full ramifications, the only survivors
should have been marine life that can feed entirely on suspended organic
detritus like bits of decaying bodies.  In short, the kind of impact
blast currently being proposed should have put life back to a Cambrian
or even Late Precambrian stage.  

The asteroid theory doesn't work.  The effects it predicts don't appear
in the record, and the effects that do appear in the record don't make
any sense as the handiwork of an impact.  

> If a geologist told me that a
> hypersonic firestorm roasted North America, and he had evidence to
> back it up, I'd have a hard time refuting that because (what we know
> so far of) the fossil record didn't show (our estimations of) the
> expected effects.

So are we supposed to ignore the facts because a theory is too elegant
and emotionally appealing?  

-- JSW