Salinity measurement of 4-micrometer fluid inclusions with microthermometry to understand chemical compositions of subduction-zone fluids

Abstract

Geochemical analysis of island-arc basalts and high-pressure and high-temperature experiments suggest that subduction zone fluids contains Cl (Kawamoto et al., 2014, Earth Planets Space). In order to know the salinity of subduction-zone fluids, we have determined it in mantle peridotite xenoliths (Kawamoto et al., 2013, Proc. Natl. Acad. Sci. USA; Kumagai et al., 2014, Contrib. Mineral. Petrol.) and high-pressure metamorphic rocks. I will present tips to determine the salinity of small fluid inclusions in the metamorphic rocks.