A total of 34 samples (35 cm average sample spacing) were analysed for organic carbon d13C in order to identify the two characteristic positive excursions associated with the Lower and Upper Kellwasser Events. Measurements were carried out at the Analytical, Environmental and Geo-Chemistry Research Group (AMGC) of the Vrije Universiteit Brussel (Belgium). The samples were decarbonated with 10% HCl in two steps, rinsed with milliQ water, and dried in an oven at 50°C. Total organic carbon (TOC) contents and δ13Corg compositions were determined on a Euro EA 150 Elemental Analyzer (CHNS) - Euro Vector HT-PyrOH combustion system coupled to a Nu-Instruments Horizon 2 isotope ratio mass spectrometer. The results were calibrated using two international standards, IAEA-C6 (sucrose: δ13C = -10.45‰) and IA-R068 (soy protein: δ13C = -25.22‰), together with reference material IVA33802151, which is calibrated against these international standards (organic-rich sediment: δ13C = -28.85‰). This calibration was verified with a further reference material, IVA33802153 (organic-rich soil: δ13C = -22.88‰).