title: Decomposition of the laboratory gamma irradiation component of angular ESR spectra of fossil tooth enamel fragments.
abstract: Spectrum decomposition of the angular measurements of fossil tooth enamel fragments using an automated simulated annealing (SA) procedure shows that the mix CO(2)(-) radicals generated by laboratory irradiation is significantly different to that of the natural sample. The naturally irradiated sample contains about 10% of non-oriented CO(2)(-) radicals and a mix of 35:65 orthorhombic to axial CO(2)(-) radicals. In contrast, laboratory irradiation generated about 40% of non-oriented radicals and a large amount of orthorhombic CO(2)(-) radicals, while we failed to detect any axial CO(2)(-) radicals. The results indicate that geological aging of the sample incurs various annealing and transfer processes; their precise nature is yet unknown. Nevertheless, the understanding of the formation and transfer processes that leads to the observed mix of CO(2)(-) radicals in fossil tooth enamel is essential for the reliable application of ESR dating.
authors.affiliation: Research School of Earth Sciences, The Australian National University, Canberra, ACT, Australia. renaud.joannes-boyau@anu.edu.au
authors.forename: Renaud
authors.initials: R
authors.lastname: Joannes-Boyau
authors.forename: Rainer
authors.initials: R
authors.lastname: Grün
authors.forename: Thomas
authors.initials: T
authors.lastname: Bodin
mesh_terms: D002248:Carbon Monoxide / Q000032:analysis*; D003743:Dental Enamel / Q000737:chemistry*; D005580:Fossils; D005720:Gamma Rays; D006801:Humans; D055110:Radiometric Dating / Q000379:methods*; D013051:Spectrometry, Gamma / Q000379:methods*
chemical_list: D002248:Carbon Monoxide