Re: Skeletal apatite again

["CN. Trueman" <C.N.Trueman@xxxxxxxxxxxxx>]

  Hello again, I hoped this might reappear.

  Cindy, I'm interested in what king of Ca/P ratios you find in the
apatites you measure. Are they constant within assemblages? Is there any
measurale correlation with total REE levels? 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).

 Cindy, where you asking about preferential uptake of REE's by apatite? I
thought that there was a 'mid range bulge' centered around Nd-Pm,
essentially due to ease of Ca substitution. This appears to be fairly
easily overprinted by natural pore water fractionation. I don't know of
any experimental studies looking at fractionation of REE's by biogenic
apatite - In fact that's something I'm quite interested in at the moment -
If anyone has any ideas/info I'd be happy to hear.

  Has anyone who has constant REE patterns within different elements of an
assemblage studied variation in other trace elements and major elements?
  Has anyone found any crystal lattice distortion effects attributable to
REE incorporation?

  I think I'd better stop now, or you'll have forgotten everything else.

	Clive Trueman (glcnt@bristol.ac.uk)