Análisis petrológico de migmatitas estromatíticas de la quebrada El Retamo, Sierra de Valle Fértil, San Juan

CASTRO DE MACHUCA, BRÍGIDA; DELPINO, SERGIO; ABARCA, ULISES; PALACIO BALDERRAMO, GLADIS; FERRARINI, PAOLO

Córdoba

Congreso; XIII Congreso de Mineralogía, Petrología Ígnea y Metamórfica, y Metalogénesis (XIII MINMET - IV PIMMA); 2019

Asociación Mineralógica Argentina y la Comisión Científica de Petrología (ComPetro) de la Asociación Geológica Argentina

Along El Retamo creek, in the northern sector of Sierra de Valle Fértil,migmatic rocks with stromatitic structure derived from metasedimentary protoliths are found. They are characterized by the presence of cordierite nodules, biotite-garnet schlieren and calcsilicate-rich and mafic resisters. Anatectic origin of cordierite nodules in country-rocks migmatites, the association observed in calcsilicatic-rich resisters Pl+Grt+Cpx+Hbl+Qtz arranged in a granoblastic-polygonal texture and deformation mechanisms in minerals, point out that the study region reached very high temperature metamorphic within granulite facies conditions. Deformation mechanisms identified in minerals of the migmatites, as ductile deformation features observed in feldspars and chessboard extinction in quartz, indicate minimum temperatures above 700 °C at an estimated pressure of around 5 Kb, which agree well with the physical conditions suggested by the stability of mineral associations mentioned above. The results of this work constitute a new contribution to the knowledge of the tectonometamorphic evolution of the scarcely explored northern sector of the Sierra de Valle Fértil, and to the establishment of correlations with that observed in previous studies in other locations of the orogen.