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RE: Sulfate 'n soot kills dinos!



Tom, et al:

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].

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! :-)

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.

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

Hope this helps.

Allan Edels

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
trlipka@directvinternet.com
Sent: Saturday, March 16, 2002 9:23 PM
To: dinosaur@usc.edu
Subject: Re: Sulfate 'n soot kills dinos!



Hi John,

>
> According to Kevin Pope in _Impact dust not the cause of the
> Cretaceous-Tertiary mass extinction_, Geology, Feb 2002, pp99-102, impact
> dust is not the cause of the Cretaceous-Tertiary mass extinction.

Haven't read the paper althouhg I have the issue in question but you have
piqued
my curiosity!
So before I get clobbered for what follows, I am speaking in only VERY
general
terms. The K-T impact and impact-extinctions for that matter ar beleive it
or no,
the other obsession in my research and one that I spent much time on before
the
Arundel project went into high gear. Thus, all of my K-T refs are somewhere
and
not readily available.

> Can anyone tell me how this works--
>
> Is there lots of acid rain (frog-killing acid rain)?

I would assume so. There have been a couple papers in Both Geology and
Science
but I do remember one that rebutted the Strangelove Ocean hypothesis.
regardless,
I'd say some major acid rains followed for some time. Retallack had a paper
in
Geotimes on this .

>
> Do all forests start burning, even wet tropical forests?

Absolutely! There was a Nature paper called something like "Wildfires at the
K-T..." ca. 1991 with a bunhc of calculations that showed even wet forest
litter
within a certain range could spontaneously ignite as a result of thermal
radiation. And speaking from a Nuclear bomb point of view (another interest
I
have, there is hard data that shows that from say a 10 MT thermonuclear
blast,
thermal radiation is capapble of causing spontaneous ignition in  dry
material ot
to 30 mile from ground zero. Naturally a much closer ranges, moist material
or
water containing objects like people also flame up spontaneously too. Ouch!

>
> What is the length of time sulfate remains aloft compared to dust?

I _think_ the "half-life" of sulfate aerosols is only a few years. For
example,
the aerosols lofted by Mt. Pinatubo hung around for a couple years but their
most
profound effects were within the first year with a measured cooling of the
global
climate.
>
> Is this modeled anywhere?

Mostly based on volcanic models involving but I do seem to remember a much
publicezed and controversial experiment carried out in Canada a few years
back
when Sagan was alive (and who pushed for it) to test the so called 'Nuclear
Winter' hypothesis. It seems some vast forrested part of the Great White
North
was taken over by some "scrub" trees and they wanted to torch it to see if
the
particulates released from this burning could be detected in the global
scheme of
things and to see if (scaled up a few orders of mag) could influence the
climate.
After some controversey with some environmentalists and others of the
soundness
of this, it finally did occur but the results, IIRC were not that great. Oh,
and
before I forget, the other imperative for torching this vast chunk of trees
was
to remove the invading shrubs and allow for the recolinization of native
species-
a tactic used widely. The difference was the considerably larger scale.

>
> Does rain take it out of the atmosphere?

Over a few rears to deacdes yes.



> Would you expect a global signature--is there one?

See above.

>
> Does this fit the extinction pattern as-well-as, or better-than, the dust?


I am sure is was a major contributing factor but there are some aspects of
it
that I am not so sure about and likely have forgotten about since my
attention
has long since turned elsewhere. I'll _try_ to look for them later this week
or
so whilke I am doing my Spring cleaning!


Cheers,
Tom

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