Pan-African high-grade metamorphism of southern Sinai, Egypt, fluid inclusion evidence

Abstract

Fluid inclusions in the leucosomes of Wadi Feiran migmatites showed that CO 2 , H 2 O and (H 2 O-CO 2 ) fluids were likely to have been present when partial melting began in these rocks. Low salinity, aqueous fluid, to a lesser extent, CO 2 -rich fluids are the most abundant fluids. The present study suggests that high-density CO 2 inclusions were formed at the earliest stage, while H 2 O inclusions were formed at the late stage. In an intermediate stage, low-density CO 2 and H 2 O, CO 2 inclusions were formed. At the early stage of uplift and during melt crystallization, the CO 2 -bearing vapour was trapped at grain boundaries. At the late stage of uplift, H 2 O released at the time of crystallization of the melt was trapped as inclusions.