Extended Data Table 1 | Ruthenium isotope data for ultramafic rocks
*The term ‘replicate’ indicates that the Ru isotope data were obtained for a replicate digestion of the same sample powder.
†H, harzburgite; D, dunite; Chr, chromitite; Kom, komatiite.
‡Number of analyses of the same sample solution.
§Ruthenium isotope data are internally normalized to (^99) Ru/ (^101) Ru using the exponential law and are reported as ε unit (0.01%) deviations from the terrestrial bracketing standard:
εiRu = (iRu/^101 RuSample / iRu/^101 RuStandard – 1) × 10^4 , where i = 96, 98, 100, 102 or 104. For samples measured n < 4 times, the quoted errors reflect the external uncertainty as defined by the standard
deviation (2 s.d.) of replicate digestions and repeated analysis of a reference sample (see Methods). Uncertainties for samples measured n ≥ 4 times are given as 95% confidence intervals of the
mean calculated as (s.d.×tn0.95,−n 1 )/.
||Calculated averages for samples from IGC and Bushveld Complex with 95% confidence interval uncertainties calculated as (s.d.×tn0.95,−n 1 )/ and 2 s.d. uncertainties.
¶Elevated ε (^96) Ru value due to an isobaric Zr interference that could not be corrected during the isotopic measurement (see Methods). Consequently, this value was not included for the
calculation of the IGC mean value.