Petrology and thermobarometric estimates for metasediments, orthogneisses, and eclogites from the Nevado-Filabride Complex in the western Sierra Nevada (Betic Cordillera, Spain)

Using PERPLE_X and garnet isopleth thermobarometry we tested whether Permian metasediments, orthogneisses, and amphibolitized eclogites from the Nevado-Filabride Complex in the western Sierra Nevada (Betics, Spain) underwent the same high-pressure metamorphism, or whether the different lithologies were tectonically emplaced after metamorphism as is commonly assumed. Our results highlight the role of some accessory minerals, especially small inclusions of Ti-bearing phases (mainly titanite and rutile) in garnet, in the thermobarometric estimates and indicate the presence of several populations of garnets in the orthogneisses-recording different stages of the prograde and retrogressive Alpine metamorphic path-in addition to pre-Alpine garnets. The schists also contain two populations of garnet: rare detrital grains and metamorphic crystals. Despite the scarcity of key phases proving that the orthogneisses and metasediments experienced high-pressure conditions, this study yields a number of lines of evidence suggesting that both rock types followed a clockwise pressure-temperature path similar to the eclogites, reaching peak pressures of 2.0-2.2 GPa for temperatures of 550-600 degrees C, and that the lithologies were all in contact prior to the high-pressure Alpine event.