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Re: Ceratopsian mass estimates




On Thu, 21 Apr 2005 22:57:30 +0200 David Marjanovic
<david.marjanovic@gmx.at> writes:
> > Subtracting the weight added by permineralization,
> 
> How could this be done? By finding an acid that etches away one of 
> the 
> materials (most probably the genuine bone) but not the other and 
> then 
> weighing the insoluble remains? :-/ 


Doing a "point count" of a thin section of a small piece of the fossil
bone should give a pretty good percentage of any added minerals.  Since
Weight(of the added mineral) = Density(of the mineral) X Volume(of the
bone), the total weight of added minerals can be calculated.

Upon further reflection, however, I don't think there is an easy way to
calculate the original weight of a fossil bone.  There are too many
variables to consider:  1) Permineralization 2) Retention/Loss of bone
collagen 3) Density change via recrystallization of the bone apatite 4)
Degree of bone vascularization.  Etc. etc. etc.

Many T. rex elements from the Hell Creek Fm have experienced very minimal
permineralization and minimal recrystallization (see the work of Mary
Schweitzer et al.), yet these elements are still *much* heavier than an
equivalent size modern bone.

A redressing or an expansion of these points may make a neat little
senior thesis.

<pb>
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