Extended Data Figure 4: 40Ar/39Ar dating results.
From: Age and context of the oldest known hominin fossils from Flores
a, Age probability plot for single crystal laser fusion data for hornblende from the Pu Maso ignimbrite (sample FLO-15-15; Supplementary Information Table 5); the vertical scale is a relative probability measure of a given age occurring in the sample57. We applied an outlier-rejection scheme to the main population to discard ages with normalized median absolute deviations of >1.5 (ref. 58) and these are shown as open circles. %40Ar* refers to the proportion of radiogenic 40Ar released for individual analyses. The weighted mean age of the filtered hornblende data for the Pu Maso ignimbrite is 0.81 ± 0.04 Ma (1σ; mean square of the weighted deviates (mswd) = 0.59, prob = 0.93; n = 23/29). b, An inverse isochron plot for these 23 analyses gives a statistically overlap** age of 0.78 ± 0.07 Ma (1σ; mswd = 0.6, prob. = 0.92). The 40Ar/36Ar intercept of 303 ± 10 is statistically indistinguishable from the atmospheric ratio of 298.6 ± 0.3 (ref. 59), thus supporting the more precise weighted mean age result.