Fluid inclusion studies on the Pan-African migmatites of Wadi- Feiran, southern Sinai, Egypt

Fluid inclusions in the leucosomes of Wadi Feiran migmatites show that CO₂, H₂O and (H₂O-CO₂) fluids were likely to have been present when partial melting began in these rocks. Low salinity, aqueous, and to a lesser extent CO₂-rich, fluids are the most abundant. The study suggests that high density CO₂ inclusions were formed at the earliest stage, while H₂O inclusions were formed at a later stage. In an intermediate stage, low density CO₂ and H₂O-CO₂ inclusions were formed. At the early stage of uplift and during the melt crystallization, the CO₂-bearing vapours were trapped at grain boundaries. At the late stage of uplift, H₂O released at the time of crystallization of the melt was trapped as inclusions. -Author