Pb was extracted from whole-rock powder splits by dissolution followed by electrodeposition technique of Arden & Gale (1974), doi:10.1021/ac60337a037. Cathodic electrodeposition was carried out twice prior to anodic electrodeposition in order to ensure removal of all Fe prior to analysis. Samples were mounted on a single Fe filament using silica gel-phosphoric acid activator and the analyses were made on the Oxford 12-in. solid source mass spectrometer designed by Dr. N.H.Gale. Pb-isotope data have been corrected for mass fractionation by comparison with results on standard NBS 981. Typical errors on Pb-isotopic ratios are 0.1-0.15% (2 sigma). Sr was extracted from powder splits by standard ion-exchange methods (O'Nions, Pankhurst, 1973; doi:10.1016/0009-2541(73)90110-1), and analysed on a V.G. MM-30 mass spectrometer at Oxford. 87Sr/86Sr ratios have been normalised to a value of 0.70800 for the Eimer and Amend Sr standard. Typical errors on 87Sr/86Sr measurements are 0.01%.