Radiocarbon dating tooth enamel
U), l’application des méthodes paléodosimétriques (OSL, TL, ESR) requiert l’acquisition de données provenant non seulement de l’échantillon, mais également de son environnement proche.
Pour la datation par Résonance de Spin Électronique (ESR) d’émail dentaire, les données relatives à l’échantillon et à son contexte sédimentaire sont indispensables à la reconstruction des débits de dose associés.
Equid teeth are also appropriate, although it should be taken into account that the porosity of the cement covering the external side of the enamel can lead to some issues regarding U-uptake modelling.
If these species are lacking from the faunal assemblage, smaller teeth, from species such as cervid and ovicaprid, can be collected, whereas carnivora teeth are usually not recommended, given their thin enamel layer; – the selected tooth should preferentially be well preserved, as previous studies show a direct correlation between fractures and diagenetic weaknesses in dental tissues and preferential migration of U-series elements (e.g.
In contrast, the dose rate is evaluated by measuring the radioactivity in the tooth itself (in all the dental tissues constituting the tooth, i.e.
enamel, dentine and, sometimes, cement) and in its surrounding (sediment, rocks, etc.).
Indeed, for Electron Spin Resonance (ESR) dating of tooth enamel, the origin of the sample as well as its sedimentary context must be well known to ensure an accurate dose rate reconstruction.Consequently, we advise that the tooth should be collected with at least 150 g of its embedding sediment. It can be done either by inserting TL or OSL dosimeters, which will record the gamma dose rate for at least several months, and/or using a portable gamma spectrometer, which can provide rapid dose rate measurements (in 10 to 30 min).Both kinds of measurements should be done at a 30 cm horizontal depth within the targeted stratigraphical unit, in order to make sure that only the radioactivity of the sediment is recorded.The sediment sample must be wrapped in a plastic bag and sealed with tape to avoid a dry out in order to ensure a correct evaluation of its water content (in weight %); measurement of radioactivity and to derive the external gamma dose rate.If not, the gamma dose can be evaluated from radioelement contents of the sediment collected as indicated above.