Python scripts, MacArgonXML and spreadsheets from the paper "Thermochronology and the apatite U–Pb geochronometer"

We re-analysed existing experimental data using a multi-domain diffusion (MMD) model, and thereby discovered considerably more refractory parameters for the diffusion of Pb in apatite: we estimate an activation energy >~311 kJ/mol with frequency factor ~1.01e-4 m2.s-1 Diffusion makes fixed temperature limits problematic, but it is still possible to define a zone in which partial retention and partial loss (PRPL) will be significant. Quasi-steady-state for a 100µm grain size shifts estimates of the lower bounds of the PRPL zone >~75°C higher than previous diffusion parameters would allow. But apatite U-Pb growth ages will not instantly reset if later thermal events cause temperatures that transcend these values, and it is clear that apatite U–Pb ages can survive later thermal events, especially at depth, since activation volume is likely to be large. Moderated python scripts and spreadsheets produced by ChatGPT are included for generation of charts and heat maps.