Cl-rich minerals in Archean granulite facies ironstones from the Beartooth Mountains, Montana, USA: Implications for fluids involved in granulite metamorphism

The implications of Cl-rich minerals in granulite facies rocks are discussed. Results from ironstones of the Beartooth Mountains, Montana are discussed. It is suggested that CO2-brine immiscibility might be applicable to granulite facies conditions, and if so, then aqueous brines might be preferentially adsorbed onto mineral surfaces relative to CO2.