Water drag, gas lift and skeletal element weight. WAS Re: Fastovsky vs Archibald

[Aidan Karley <aidan_karley@yahoo.co.uk>]

In article <20050623001611.39447.qmail@web80410.mail.yahoo.com>, Guy Leahy 
wrote:
> For disarticulated elements, this was likely, though it would have taken a 
> pretty 
> big stream to move a Triceratops skull... :-)
>
       This begs a fairly obvious question to me ... as a carcass decomposes, 
some 
parts of it are going to produce gases, which in an aquatic transport situation 
is 
going change the (buoyant volume)/weight relation. To quote murder movies /ad 
nauseam/ 
and Discovery Channel's murderous late-night transmissions, the body will try 
to float 
to the surface. Specifically, elements like skull and pelvis are going to be 
good 
candidates for trapping flesh and consequent gases where nibbling teeth have a 
job 
getting at them. Further, both skull and pelvis have substantial "wings" of 
bone 
that would make for considerable hydrodynamic drag.
       So, what I'm thinking is that the amount of flow that would be needed to 
shift 
a Trike skull in particular, may well be less than one would initially expect.
       
       Are skulls and pelvic girdles comparatively common as isolated elements? 
Compared to, say, limbs (where the gases can leak out along the bones) or 
vertebrae 
(similarly).

       Come to think of it, using the same logic, partial wings ought to be 
comparatively common too. And *that* I can say I've seen regularly as a 
proto-fossils 
blowing around Scottish hillsides, or polluting the streams (just upstream from 
where 
I've been drinking, naturally).

-- 
 Aidan Karley,
 Aberdeen, Scotland,
 Location: 57°10' N,  02°09'  W (sub-tropical Aberdeen), 0.021233
 Written at Thu, 23 Jun 2005 07:26 +0100



        
        
                
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