Datación Sm-Nd del metamorfismo en ía Sierra de las Imanas (Sierras Pampeanas Occidentales, Argentina)

Abstract

Sm-Nd garnet geochronology of a migmatite gneiss from the Sierra de las Imanas (Western Sierras Pampeanas) has provided a peak metamorphic age of 464.6 ± 4.5 Ma, i.e., Middle Ordovician, corresponding to the Famatinian orogeny of Western Argentina This age agrees with metamorphic ages obtained in nearby areas by U-Pb SHRIMP dating of zircon overgrowths. This coincidence confirms the reliability of the Sm-Nd garnet chronometer in the study of metamorphic terranes. A Proterozoic Toxt age of 1628 Ma suggests the involvement of an old recycled crustal component in the sedimentary protolith of the migmatite