FISSION TRACK TEMPERATURE AGE THEORY

Abstract

As a consequence of thermal fading of fission tracks in minerals the fission track dating method can be used to obtain a temperature (cooling) age, if it is possible to determine the temperature associated with a measured fission track age. Based on the concept of a minimum measurable fission track length, lmin (Märk and others, 1973) we have recently solved for apatite the differential annealing equation dl/dt = -αt taking into account that the annealing coefficient, α = α(T) depends also on the fission track reduction p/pO. This calculation yielded an improved age-temperature relationship (Bertagnolli and others, 1981a). We could demonstrate in this study, however, that to a good approximation it is sufficient instead to use an annealing coefficient, where p/p0 is substituted by a constant (high) degree of reduction. In the present study we have used this approximation to calculate age-temperature relationships for a number of minerals using annealing data given by Saini and Nagpaul (1979).