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RE: Sulfate 'n soot kills dinos!



Hi Allan,
> 
> One thing to be considered is the trajectory of the bolide.  If the angle of
> approach to the Earth's atmosphere is sufficiently shallow (but not so
> shallow that the bolide skips out of the atmosphere), the ozone layer can be
> reduced to 10% of its normal amount (most likely via ionization).  This
> would be prior to the actual impact onto the Earth's surface.  [This study
> (a computer model actually) was once mentioned in a nature special - Dr.
> Bill Gallagher was the host].

I do remember watching the program you mentioned but it has been a while.
However, I do have a problem with the volume O3 allegedly depleted. It was one
thing that stuck out with me about the program because it was made with no data
to back it up, no numbers no nothing. I try not to take such statements at face
value. Just think, the K-T impactor was about 10 Km wide. The main (most of the
air) part of our atmosphere is about 16 KM. Now a large mountain slamming 
through
the atmosphere at over 30 Km/sec (or even half that for that matter)assuming a
normal trajectory would have spent a fraction of a second in the atmosphere b
efore impact. Now an oblique impactor, such as the K-T is believe to be (~30
degrees from the SE IIRC) would naturally spend a little more time but still 
only
a second or so. So my contention is that the object could not have spent as much
time in the atmosphere per se, to do that much damage to the upper O3 layer. 
> 
> After the actual impact into the surface (land & water), then the soot and
> dust, etc. would also deplete the ozone layer even further.  Once the skies
> had cleared (after the greenhouse effect, etc.), the lack of ozone would
> mean Ultraviolet radiation would shine on the earth virtually unhindered.
> This would cause really, really bad sunburn to anything still wandering
> around! :-)
> 
I have not doubt that the Ozone layer was dmaged but to what degeree and by 
what?
Stratospheric O3 breaks up mostly by interaction with radiation and not soot.
Soot tends to absorb certain wavelenths and dust, depending on the tyoe absorbs
or reflects radiation. The only other processes am aware of that inhibits O3 are
CFC's (manmade) and various natural CL emissions.


> The acid rain has been part of the scenario (K-T extinction via bolide
> collision), about 2 years after the Alvarezes first brought out the initial
> idea.
> 
> Besides that, the increased UV radiation, and other radiation (X-ray, Cosmic
> Rays, Solar Flares, etc.), the surviving creatures would most likely have
> increased mutation rates.  This would certainly enable rapid evolutionary
> changes.
> 

Are you implying a global depletion or complete stripping of O3?


> One signature from this event (specifically the soot) would be the presence
> of "Bucky Balls" (in certain fossils).


They have been found. I have at least one or two buried refs on this subject as
well. However, I have before me the March 2002 issue of Scientific American that
contians an article by Luann Becker "Repeated Blows", p. 76-83  which discusses
the hunt for impacts and their potential or hitrory of causing mass extinctions.
I have only glossed over it but I do see mention of fullerenes. I like the chart
on p. 79 that shows the temporal relationships of a number of impacts,
extinctions and flood basalt volcanism. It gets one thinking.

I think it is best to end the discussion here as the subject at hand is not
completely dinosaur related. Feel free to email me off list, and likewise, if I
can come up with the refs, I'll fire them off to those interested.

Cheers,

Tom

Thomas R. Lipka
Geobiological Research
2733 Kildaire Drive
Baltimore, Md. 21234 USA