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doi:10.2204/iodp.proc.322.212.2016

Analytical methods

The isotopic composition of oxygen was measured in pore fluid samples recovered from Sites C0011 and C0012 at the Institut de Physique du Globe de Paris (IPGP). A pore water aliquot (0.8 mL) sample was equilibrated with a He + CO2 gas mixture at 25°C for 8 h, and the 18O/16O ratio on the CO2 gas phase was measured with an isotope ratio mass spectrometer interfaced with gas chromatography (GC-IRMS; Analytical Precision 2003). The measurements were calibrated using a set of three house water standards calibrated versus standard mean ocean water (SMOW). δ18O are reported against the SMOW standard scale. Measurements of δ18O were determined with an analytical accuracy better than ±0.1‰.