Pb-Pb isochrons for materials of the some of the oldest material in the solar system from three meteorites (Connelly et al., 2012). (A) Efremovka meteorite CAI 22E (4567.35 ± 0.28 My), (B) Allende chondrule C30 (4567.32 ± 0.42 My), and (C) NWA 5679 chondrule C2 (4564.71 ± 0.30 My).