Major and minor elements data of Kumano mud volcanoes' pore waters extracted from cores taken during the SO222 expedition in 2012.Major and minor elements were measured via a PerkinElmer 3000 Optical Emission Plasma Spectrometer at the Scripps Institution of Oceanography with an uncertainty of better 4% 2SD from the acidified samples diluted at ratios of 100:1 (Na, Mg, Ca, S, Sr, K, Li, B) and 10:1 (Li, B, Si, Ba, Fe, Mn) (House, 2019). For selected samples with low salinity, chloride concentrations were determined by silver nitrate (AgNO3) titration with potassium chromate/di-chromate indicator (Gieskes et al., 1991), calibrated against repeated titrations of an IAPSO standard seawater. Additional subsamples were also analyzed for concentrations of sulfate (SO4) and chloride by ion chromatography (Metrohm 850 Professional IC) using aliquots of 100 µL diluted 1:100 with deionized water (18 MΩ•cm).

Further funding:* FWF Lise Meitner, Award: M3146-N