Problems in determining lifetimes of esr signals in natural and burned flint by isothermal annealing signals in natural and burned flint by

ESR signals in microcrystalline quartz (flint) are zeroed by burning and their regrowth can be used to date flint artifacts. We have attempted to determine the mean lives of the dating signals, E′ and A1, in natural and burned flint by two methods, isothermal annealing and steady state/saturation. Isothermal annealing experiments were conducted at 100°C < T < 400°C and the mean lives at 15°C were extrapolated from these data. Flint that has been heated either archaeologically or in the laboratory gives anomalously low mean lives, <- 100 yr, for both signals. This is inconsistent with the observation that experiments carried out on burned flint recovered from archaeological sites give equivalent dose values comparable to exposure histories of > 105 yr. The isothermal annealing experiments on natural flint gave mean lives of circa 107 …