The scapolite-bearing metapelites come from the Nevado-Filabride complex (Betic Cordilleras). They are biotiterich fine-grained rocks containing large scapolite porphyroblasts. The evaporitic origin of these metapelites is deduced from its chemical composition and the occurrence of scapolite, anhydrite, barite and gypsum pseudomorphs. The mineralogical and textural features indicate two metamorphic events. The poT conditions of the first one are establisshed 16-17 kbars and 560-690°C on the evidence of the stable coexistence of kyanite + phengite + talc. This paragenesis is the highest-pressure association so far reported in the Nevado-Filabride metapelites. The scapolite grew in the second metamorphic event, as its clearly helicitic character indicates, and was stabilized due to the higher Cl activity in the fluid phase. The PoT conditions of this event are established about 550°C and 6 kbars on the basis of the chlorite + quartz coexistence and the garnet-biotite geothermometer. The evaporitic origin of the scapolite-bearing metapelites and the associated metasediments support a continental setting for the mafic igneous rocks intruded in this sequence.
La asociación de alta presión distena + talco + fengita coexistente con escapolita en metapelitas de origen evaporítico (Complejo Nevado-Filábride, Cordilleras Béticas)
CAMARA ARTIGAS, Fernando
1990-01-01
Abstract
The scapolite-bearing metapelites come from the Nevado-Filabride complex (Betic Cordilleras). They are biotiterich fine-grained rocks containing large scapolite porphyroblasts. The evaporitic origin of these metapelites is deduced from its chemical composition and the occurrence of scapolite, anhydrite, barite and gypsum pseudomorphs. The mineralogical and textural features indicate two metamorphic events. The poT conditions of the first one are establisshed 16-17 kbars and 560-690°C on the evidence of the stable coexistence of kyanite + phengite + talc. This paragenesis is the highest-pressure association so far reported in the Nevado-Filabride metapelites. The scapolite grew in the second metamorphic event, as its clearly helicitic character indicates, and was stabilized due to the higher Cl activity in the fluid phase. The PoT conditions of this event are established about 550°C and 6 kbars on the basis of the chlorite + quartz coexistence and the garnet-biotite geothermometer. The evaporitic origin of the scapolite-bearing metapelites and the associated metasediments support a continental setting for the mafic igneous rocks intruded in this sequence.
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