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Re: Coprolites (or "Why X-ray paleo-poop?")
Phillip Bigelow wrote:
> Fossil biogenic apatites that have not been subsequently altered
> (replaced or recrystallized) always had a uniform crystallite diameter
> and have a preferred crystallite orientation. When the specimen is
> ground-up and placed in a powder mount, these characteristics are
> maintained (the xls self-align slightly due to the handling process).
> The pattern was skewed slightly and sometimes had a moderate degree of
> peak kurtosis. In contrast, mechanically-powdered
> non-biologically-formed apatites show the typical random cleavage planes
> and shapes of the igneous (and diagenetic) mineral apatites. These
> feature showed up on the X-ray diffraction pattern in the form of much
> more symmetrical diffraction peaks.
Just out of curiosity, could this difference be enhanced? I've never seen the
and don't know the mechanics, but I was thinking of something in the nature of
the sample onto the X-ray target as a packed monolayer on acetone (or some
reasonably polar solvent).
I'm also wondering if the differences you describe would show in a coprolite
Since the apatite content is pretty low, would there be much tendency for the
to orient with respect to each other? Or are you talking about a sample after