Time lag between metamorphism and crystallization of anatectic granites (Córdoba, Argentina)

D´ERAMO, F.J.; ESTEBAN, J.J.; CONIGLIO, J.E.; DEMARTIS, M.; ARAGÓN, E.; PINOTTI, L.P.

GEOLOGICA ACTA

UNIV BARCELONA

Lugar: Barcelona; Año: 2020 vol. 18 p. 1 - 14

1695-6133

SHRIMP and LA-ICP-MS analyses carried out on zircons from the Río de los Sauces granite revealed theirmetamorphic and igneous nature. The metamorphic zircons yielded an age of 537±4.8 (2σ)Ma that probablypredates the onset of the anatexis during the Pampean orogeny. By contrast, the igneous zircons yielded a youngerage of 529±6 (2σ)Ma and reflected its crystallization age. These data point to a short time lag of ca. 8Myr betweenthe High Temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. Concordia ageof 534±3.8 (2σ)Ma, for both types of zircon populations, can be considered as the mean age of the Pampean HTmetamorphism in the Sierras de Córdoba.