Rehydroxylation dating
This thesis is concerned with a better understanding of issues which currently limit the precision, accuracy and robustness of rehydroxylation (RHX) dating. MC simulations and analytical expressions show that age uncertainties of previous studies are underes- timates. The ratio of sample mass to balance resolution should be of the order of 10<sup>-6</sup> or less for measurement precision under 1%. A combined measurement uncertainty of ~ 4 % should be possible, given well-designed experiments, appropriate samples, and a t<sup>1/N</sup> model with N = 4. Highly-fired materials have an age limit of ~ Ma, but low &alpha; and y<sub>max</sub> preclude dating materials such as porcelain. There is little correlation between non-stabilisation of m<sub>2</sub> and factors such as porosity, specific heat capacity or density. The strongest effect is that of sample dimension (thickness), which is found to cause long times to stage II mass gain following 105 Â°C heating - roughly proportional to the thickness squared, suggesting some long-lived contribution from Fickian diffusion. Another strong effect is acceleration of the rehydroxylation reaction upon cooling from high temperatures, which is also dependent on sample
Hare, Vincent John
Rehydroxylation dating. This thesis is concerned with a better understanding of issues which currently limit the precision, accuracy and robustness of rehydroxylation (RHX) dating. MC simulations and analytical expressions show that age uncertainties of previous studies are underes- timates. The ratio of sample mass to balance resolution should be of the order of 10<sup>-6</sup> or less for measurement precision under 1%. A combined measurement uncertainty of ~ 4 % should be possible, given well-designed experiments, appropriate samples, and a t<sup>1/N</sup> model with N = 4. Highly-fired materials have an age limit of ~ Ma, but low &alpha; and y<sub>max</sub> preclude dating materials such as porcelain. There is little correlation between non-stabilisation of m<sub>2</sub> and factors such as porosity, specific heat capacity or density. The strongest effect is that of sample dimension (thickness), which is found to cause long times to stage II mass gain following 105 Â°C heating - roughly proportional to the thickness squared, suggesting some long-lived contribution from Fickian diffusion. Another strong effect is acceleration of the rehydroxylation reaction upon cooling from high temperatures, which is also dependent on sample
dating concerned good issue currently limit precision accuracy robustness dating simulation analytical expression show age uncertainty previous_study ratio sample mass balance resolution order less measurement precision combine measurement uncertainty possible give well designed appropriate sample model highly fired material age limit low preclude date material porcelain little correlation non stabilisation factor porosity specific heat capacity density strong effect sample dimension thickness find cause long_time stage mass gain follow adegc heat roughly proportional thickness square suggest long_lived diffusion another strong effect acceleration reaction upon cool high_temperature also dependent sample