Supplementary Material
Fig. S1 - A compilation of oxygen isotope data from repeated analyses of the R33 standard zircon.  Our average δ18O value of 5.5 ± 0.4‰ is within error of the reference value of 5.55 ± 0.04 (Valley et al. 2003, Black et al. 2004). All individual errors are at the 2σ level (standard error) while the shaded region shows our external reproducibility, based on 2 standard deviations of the mean.
Fig. S2 – A compilation of U-Pb ages from isotopic analyses of the 91500 zircon by HR-LA-ICP-MS.  Our average age of 1061.8 ± 2.5Ma is similar to the reference age of 1065.4 ± 0.3Ma (Wiedenbeck et al. 1995).  All error ellipses are at the 2σ level (standard error).
Fig. S3 - A compilation of U-Pb ages from isotopic analyses of the R33 zircon by HR-LA-ICP-MS.  Our average age of 417.1 ± 2.4Ma is within error of the reference age of 419.3 ± 0.4Ma (Black et al. 2004).  All error ellipses are at the 2σ level (standard error).
Fig. S4 – Hf isotopic composition of reference zircons 91500, GJ1 and Plesovice.  Average 176Hf/177Hf ratios are within error of published values (see supplementary table S3 for details).  All individual errors are at the 2σ level (standard error) while shaded regions show external reproducibility, based on 2 standard deviations of the mean.
Fig. S5 (a-f) – Tera-Wasserburg plots showing the age distribution and concordance of zircons from a) WPG90-4, b) DL90-7, c) IT-5, d) IT-12, e) IT-17, and f) IT-18.  All error ellipses are at the 2σ level (standard error).