DATACIÓN Sm-Nd DEL METAMORFISMO EN 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.A.

GEOGACETA

Sociedad Geológica de España.

Lugar: Madrid; 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 464.6 ±  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 TDM age of 1628 Ma suggest the involvement of  an recycled crustal contamination component in the sedimentary protolith  of  the migmatite.