Chlorine isotopic compositions of high temperature hydrothermal vent fluids over ridge axes

This study explores possible processes that may change Cl concentration during fluid genesis and discusses their theoretical isotopic effects. The δ37Cl homogeneity implies that, at the P-T conditions of the ridge axis, the process of phase separation (at sub- or super-critical conditions) that explains most of chlorinity variations, does not significantly fractionate chlorine isotopes. This study shows that the physical and chemical processes that likely alter Cl concentrations in ridge axis systems (i.e. transport processes, mixing or water-rock interaction) contribute to minimize the range of δ37Cl around the seawater δ37Cl value.