Figure 1.
Three isotopes plot: δ43/42Ca as a function of δ44/42Ca (‰, reference standard ICP Ca) for all samples and standards analysed for Ca isotope compositions in this study. Ca isotope compositions fall on a line with a y-axis intercept of 0.009 ± 0.015 (‰, 2 s.e.), indistinguishable from theoretical 0‰ intercept. The slope value of this line is 0.509 ± 0.016 (2 s.e.), indistinguishable from the 0.507 slope predicted by the exponential mass-dependent fractionation law. Error bars at the bottom right are average 2 s.d. for δ43/42Ca and δ44/42Ca. The two most external lines delimit the prediction interval, and the two lines accompanying the middle line correspond to the 95% confidence interval of the regression line. (Online version in colour.)