(Table 1) Boron abundance and isotopic ratios for ODP Site 125-779

B concentrations for samples of serpentine matrix were measured by isotope dilution mass spectrometry (IDMS) at the Department of Terrestrial Magnetism (DTM) (Washington, DC, USA) using the HF-mannitol method of digestion (Nakamura et al., 1992) and positive ion thermal ionization mass spectrometry of Cs2BO[+]2 (Spivack and Edmond, 1986, doi:10.1021/ac00292a010, Xiao et al., 1988, doi:10.1016/0168-1176(88)83016-7). Concentrations for the clast samples were measured by direct-current plasma emission spectrometry (DCP) at the University of South Florida (Tampa, FL, USA) using the Na2CO3 flux method of digestion (Ryan and Langmuir, 1993, doi:10.1016/0016-7037(93)90008-K). Uncertainties are less than +/- 1% for IDMS measurements and +/- 10% for DCP measurements. B isotope measurements were prepared and analyzed using methods similar to the IDMS analyses at DTM.