This data set includes the supplementary data to Schwarzenbach et al., subm., Journal of Geophysical Research. I includes major and trace element bulk rock data, rare earth element bulk rock data, bulk rock radiogenic strontium isotope, stable oxygen and hydrogen isotope data of serpentinites and ophicalcites from the Northern Apennine ophiolite sequence in Italy. In situ mineral data include rare earth element data and electron microprobe data of serpentine, amphibole, chlorite and talc. Carbonate vein data of microdrilled veins include radiogenic strontium isotope data and stable carbon and oxygen data.