First constraints of metamorphism and anatectic granites crystallization time lag at Sierras Pampeanas (Argentina)

DEMARTIS, MANUEL; PINOTTI, LUCIO PEDRO; D'ERAMO, FERNANDO JAVIER; ARAGÓN, EUGENIO; ESTEBAN GUZMÁN, JOSÉ JULIÁN; CONIGLIO, JORGE ENRIQUE

GEOLOGICA ACTA

UNIV BARCELONA

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

1695-6133

SHRIMP analysis and LA-ICP-MS studies carriedout on zircons from the Río de los Sauces granite reveal their metamorphic andigneous nature. The metamorphic zircons yielded an age of 537 ± 4.8 (2s)Ma thatprobably predates the onset of the anatexis during the Pampean orogeny.Otherwise, the igneous zircons yielded a younger age of 529 ± 6 (2s)Ma andreflected its crystallization age. These data established a short time lag ofca. 8Myr between the high temperature (HT) metamorphic peak and the subsequentcrystallization age of the granite. A Concordia age of 534 ± 3.8 (2s)Ma, forboth types of zircon populations, can be considered as the mean age of the HTPampean metamorphism at the Sierras de Córdoba.