5 resultados para bioapatite


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Réalisé en cotutelle avec le Département de Préhistoire du Muséum national d’Histoire naturelle (Paris, France), École doctorale « Sciences de la nature et de l’Homme » (ED 227)

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The density (BSG) of bone increases, at the osteon scale, during lifetime aging within the bone. In addition, post-mortem diagenetic change due to microbial attack produces denser bioapatite. Thus, fractionation of finely powdered bone on the basis of density should not only enable younger and older populations of osteons to be separated but also make it possible to separate out a less diagenetically altered component. We show that the density fractionation method can be used as a tool to investigate the isotopic history within an individual's lifetime, both in recent and archaeological contexts, and we use the bomb C-14 atmospheric pulse for validating the method.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Samples of recent to Miocene fish and marine mammal bones from the bottom of the Atlantic and Pacific Oceans and Miocene Maikop deposits (Transcaspian region) are studied by X-ray diffraction technique combined with chemical and energy-dispersive analyses. Changes of lattice parameters and chemical composition of bioapatite during fossilization and diagenesis suggest that development of skeletal apatite proceeds from dahllite-type hydroxyapatite to francolite-type carbonate-fluorapatite. It is assumed that jump-type transition from dahllite to francolite during initial fossilization reflects replacement of biogeochemical reactions in living organisms, which are subject to nonlinear laws of nonequilibrium thermodynamics, by physicochemical processes according to the linear equilibrium thermodynamics.