Figure 4. Ranked order plots for disequilibrium-corrected (U-Th)/He zircon ages for Hasan Dağı.

Individual eruption ages (red dashed lines) for samples HD (A) and HDA (B) were calculated as error-weighted averages from (U-Th)/He zircon analyses. Errors comprise analytical uncertainties plus the uncertainty for the disequilibrium correction, and are bracketed by secular equilibrium (minimum age), and the disequilibrium-corrected age that corresponds to the measured U-Th rim crystallization age, assuming that it represents the crystallization age for the entire crystal (maximum age). Zircon crystals where rim ages are in (near-) secular equilibrium thus have the lowest uncertainties. Three crystals in sample HD yield (U-Th)/He ages that are too old to be reconciled with the average of the population. We interpret them as xenocrysts from pumice of older eruptions, and thus excluded them from the average. Weighted average age errors account for systematic and analytical uncertainties, and are quoted at 2σ; error bars plotted at 1σ.