A new U-uptake model for combined ESR/U-series dating of tooth enamel
Shao
Qingfeng
Bahain
Jean-Jacques
Falguères
Christophe
Dolo
Jean-Michel
Garcia
Tristan
ESR/U-series dating
Tooth enamel
U-uptake model
journalArticle
Combined ESR/U-series dating of tooth enamel using US model implies the calculation of a specific parameter p for each dental tissue to reconstruct its U-uptake history. The US model simulates this history as a continuous incorporation process without leaching, where the 238U–234U–230Th system evolves towards secular equilibrium state. Consequently, the application of this model is restricted to the samples displaying 230Th/234U activity ratio below or close to equilibrium with maximum value of ∼1.05 for each tissue. In order to overcome this limitation, here, a new model named Accelerating Uptake (AU) model is proposed. This model describes U-uptake into dental tissue as an accelerating process by the introduction of two parameters, the initial uptake rate and the acceleration of this uptake rate. The AU model is then able to reconstruct a process combining incorporation followed by leaching, as well as continuous uptake one. With this model, the evolution of 230Th/234U activity ratio with time can reach values higher than unity, even beyond equilibrium. The AU model is useful in cases for which age estimates cannot be calculated by routine use of US model. The application of the AU model to the palaeoanthropological site of Mauer in Germany shows its potential for extending the applicability of the combined ESR/U-series dating of tooth enamel.
406-411
juillet 2012
http://www.sciencedirect.com/science/article/pii/S1871101412000349
2014-01-07 15:00:54
ScienceDirect
Quaternary Geochronology
10
Quaternary Geochronology
DOI 10.1016/j.quageo.2012.02.009
ISSN 1871-1014