Re: New refs about impacts

[David Marjanovic <david.marjanovic@gmx.at>]

If Yahoo! doesn't do it automatically (like almost everything else), could 
you please add > in front of what you quote? Currently your e-mails are a 
bit difficult to read because what you write and what you quote looks the 
same. And while you are at it, you could delete stuff to which you don't 
answer. My automatic GMX signature ("Please smile! Foto gallery online 
with GMX[, even] without a homepage of your own!") isn't so interesting 
that anyone might want to see it twice. :-) 
 
> > > So acid rain did not result from the impact? 
> > 
> > It did, and at least in some places it reached the ground 
> 
> Can we really be certain of this anymore? Those authors have a pretty 
> high regard for the acid neutralizing ability of larnite. 
 
As a silicate, larnite shouldn't be such a strong base. (Remember... 
almost all acids can be stored in glass bottles indefinitely, and glass is 
a silicate, although a very complicated and chaotic one, unlike the neat, 
tidy larnite with its small molecules.) In the long 
term, its reaction as a base (with carbonic acid during erosion) certainly 
helped get the CO2 levels back to normal, but that was still slow enough 
to let the temperature spike be recognizable in the fossil record. 
 
> > (as shown by etched shocked quartz grains), 
> 
>   Which couldn't have resulted from swamp acid? 
 
I don't know where those grains were found. But in any case I assume that 
something stronger is needed to etch sand. 
 
> > but apparently less of it reached the ground than thought earlier. 
> 
>  Enough-if any-for marine extinctions? 
 
Don't know. But in any case the marine extinctions happened, and were 
catastrophic, leaving only a Strangelove ocean for several millennia. 
 
> >  They say a "short but unknown interval" separates the Cotham Member 
> > from "biotic perturbations" associated with the end Triassic 
> > extinction. 
 
To me, this sounds like a bad and/or underresearched fossil record in that 
area. In short... W4tP. :-) 

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