Some comments on the effect of uranium zonation on fission track dating by LA-ICP-MS

The use of LA-ICP-MS for uranium determination in the fission track dating technique is becoming increasingly popular because several advantages over classical external detector method and a variety analytical statistical protocols have been developed. However, two important issues remain unresolved context approach (i) how to best deal with low density (ρs) samples, (ii) does correlation between age content (or eU) reflect an annealing dependence or not? To assess impact methodology on these issues, we compare multi-spot more single spot methods samples known ages, variably zoned and/or densities. make comparison approach, implemented Python script, that randomly our ICP-MS data choose U measurement per grain, simulating approach. We then calculate central age, p(χ2) dispersion simulated analysis repeat this 2000 times. Our results show robust ρs yielding both accurate precise without over-dispersion. Additionally, random sampling shows can induce overdispersion coupled relationship grain content. This at least partly attributable zonation creates mismatch counted area spot-measured U. Therefore, recommend if over-dispersion observed basement when one typically expects population, multiple should be carried out excess linked undetected zoning laser misplacement rather than dependent behaviour.