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Charnockites sensu lato(charnockite-enderbite series) are lower crustal felsic rocks typically characterised by the presence of anhydrous minerals including orthopyroxene and garnet.They either represent dry(H_2O-poor) felsic magmas that are emplaced in the lower crust or granitic intrusions that have been dehydrated during a subsequent granulite facies metamorphic event.In the first case,postmagmatic high-temperature recrystallisation may result in widespread metamorphic granulite microstructures, superimposed or replacing the magmatic microstructures.Despite recrystallisation,magmatic remnants may still be found,notably in the form of melt-related microstructures such as melt inclusions. For both magmatic charnockites and dehydrated granites,subsequent fluid-mineral interaction at intergrain boundaries during retrogradation are documented by microstructures including K-feldspar microveins and myrmekites.They indicate that a large quantity of low-H_2O activity salt-rich brines,were present(together with CO_2 under immiscible conditions) in the lower crust.
Charnockites sensu lato (charnockite-enderbite series) are lower crustal felsic rocks typically characterised by the presence of anhydrous minerals including orthopyroxene and garnet. They either represent dry (H_2O-poor) felsic magmas that are emplaced in the lower crust or granitic intrusions that have been dehydrated during the subsequent granite facies metamorphic event. in the first case, postmagmatic high-temperature recrystallisation may result in yet metamorphic granulite microstructures, superimposed or replacing the magmatic microstructures. Descriptive recrystallisation, magmatic remnants may still be found, notably in the form of For both magmatic charnockites and dehydrated granites, subsequent fluid-mineral interaction at intergrain boundaries during retrogradation are documented by microstructures including K-feldspar microveins and myrmekites. that indicate that a large quantity of low-H_2O activity salt-rich brines, were pr esent (together with CO_2 under immiscible conditions) in the lower crust.