Re: Skeletal apatite again

[NEIL CLARK <NCLARK@xxxxxxxxxxxxxxxx>]

> Has anyone else measured Ca/P
> ratio variation WITHIN individual bones/teeth/conodonts? I ask 
because I
> find significant variation within bones, as much as variation 
between
> bones of different sites, and I wonder how this might affect other 
trace
> element signals (as the variation in Ca/P ratios is diagenetic).


I looked at the variation of Ca:P across a cuticle of a diagenetically 
phosphatised crustacean.  The ratio increased towards the inner 
surface (away from the surface exposed to the phosphate-rich waters 
presumably) from approx 2.33-2.44 over a thickness of about 1mm.  I 
also found that the mean Ca:P correlated with the thickness of the 
cuticle suggesting that the phosphate replacement was more 
complete in thinner cuticles.  I don't know if any of this is of relevance 
to you as you specifically ask for vertebrate references.


PS. I did some REE and trace elements in other phosphatised 
sediment and compared the results to the surrounding 
non-phosphatised sediment. Answer me off the list if you want to 
know more.

Neil


Neil Clark
Curator of Palaeontology
Hunterian Museum
University of Glasgow
email: NCLARK@museum.gla.ac.uk

Mountains are found in erogenous zones.
(Geological Howlers - ed. WDI Rolfe)