A few sediment samples from the Nankai Trough have been analyzed to determine the He concentrations and the 3He/4He isotope ratios in the mineral phase. The CO(2) produced by heating the samples in a Ta furnace (i.e., the gas extraction step at up to 1800°C) was analyzed for its δ13C isotope signature.
A few months after the cruise NT14-07 on RV Natsushima, noble-gas concentrations have been measured in the pore water of sediment samples collected along the Nankai Trough. The results should extend the data set collected during RV Natsushima cruise NT13-08 (see the Expeditions section for some impressions). The evaluation of the measurements should be concluded at the beginning of September.