Fig. 9
Comparison of the isotopic compositions of KDE and those of the Arima and Takarazuka waters with the calculated, slab-derived fluid from previous research. Red and green solid lines show the calculation results of δD and δ18O in water dehydrated from a subducted slab as a function of depth for the Philippine Sea and Pacific slabs, respectively (Kusuda et al. 2014). The estimated KDE might be interpreted as a slab-derived fluid which originated from dehydration at 80–100 km in depth of the Philippine Sea slab (SW Japan, red solid curve) and its isotope exchange reactions (mainly oxygen) with minerals (yellow arrow). Andesitic magma water and Arima end-member is from Giggenbach (1992) and Kusuda et al. (2014), respectively