Extended Data Figure 8: 40Ar/39Ar results. | Nature
(See Supplementary Information section 10.) a, Total population of hornblende data, showing probability density curve, individual analyses with 1σ analytical uncertainties, and percentage enrichment in radiogenic 40Ar and estimates of the K/Ca ratios calculated from 39Ar/37Ar ratios. b, Three populations (age groups) as identified in the Trinil sample. Note that three individual analyses belong both to the ‘young’ (blue) and ‘middle’ (green) populations on statistical grounds. The error bars represent the 1σ analytical uncertainties. c, Inverse isochron representation of all three data sets showing overlap of the respective non-radiogenic intercepts with atmospheric 40Ar/36Ar ratios, and the isochron regression of the three subsets in blue (young), green (middle) and red (old) populations. The outliers are in grey. The 1σ error ellipses are in most cases smaller than the symbol size. MSWD, mean squared weighted deviate.