Figure 1.

Magnesium isotope compositions. a) Probability density plots of Mg isotope compositions from previous standard-sample bracketing work, highlighting the results of individual studies⁵,¹⁰–¹² that presented numerous analyses of both terrestrial and chondritic samples using the same methodology. These data show systematic subtle differences (0.02-0.05‰) between the Earth and primitive meteorites. Typically authors refrained from interpreting such small differences. b) Samples from this study (measured by critical mixture double spiking) ordered according to sample-type. Lines and shaded bars indicate means and 2se. Samples displayed with pale symbols are excluded from means (see main text). c) Earth and chondrite analyses from b) shown as probability plot to compare with a).