Trueman, Privat, and Field, 2008, Why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral? Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 160-167.
What’s it about?
Bones are composed of little crystals of the mineral referred to as bioapatite with organic materials (collagen, blood vessels, and cells that regulate the growth of bioapatite, etc) spread throughout. When an animal dies, the organic materials decay and the bioapatite crystals change their shape and size. There are methods by which we can readily measure the shape and size of the crystals, which, presumably, would tell us just how altered the bones are due to the fossilization process. This would then let us know how accurate any geochemical analyses we do with the bone are.
Only that the shape and size of bone crystals doesn’t actually work as a good measure of the alteration due to fossilization.
Why does it matter?
As scientists, geochemists, and paleontologists, it is important to know how well the geochemical signal of the living animals’ bones are preserved in the fossils we’re studying. Analysis of bioapatite crystal size and shape is easy and relatively cheap, so it is often used to assess the state of alteration. The authors here show that this is only partially true, and provide some means for improving our estimation of alteration.
Why did I read this?
As a geochemist, this is something I think about all the time. I have done the very analyses the authors talked about for the same reasons. I have to re-think what I’ve been doing.