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

GALINDO, C.; MURRA, J.; BALDO, E.; CASQUET, C.; RAPELA, C.W.; PANKHURST, R.J.; DAHLQUIST, J.

GEOGACETA

Sociedad Geológica de España

Año: 2004 vol. 35 p. 75 - 78

0213-683X

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± 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 coincidence3 confirms the reliability of the Sm-Nd garnet chronometer in the study of metamorphic terranes. A Proterozoic TDM age of 1628 Ma suggests the involvement of and old recycled  crustal component in the sedimentary protolith of the migmatite. Key words: Sm-Nd dating, metamorphism, Sierras Pampeanas, Argentina