Metamorphism and crystallization of anatectic granites at Sierras Pampeanas de Córdoba (Argentina): First constraints of their time lag by using U-Th-Pb SHRIMP and LA-ICP-MS zircon analyses

SHRIMP analysis andLA-ICP-MS studies carried out on zircons from the Rio de Los Sauces granite reveal their metamorphic and igneous nature. The metamorphic zircons yielded an age 537.1 ± 4.8 (2s) that probably predates the onset of the anatexis during the Pampean orogeny. Otherwise, the igneous zircons yielded a younger age of 529 ± 6 (2s) Ma and reflectedits crystallization age. These data established a short time lag of ca. 8 Myr between the high temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. A Concordia age of 533.9 ± 3.8 (2s) Ma, for both types of zircon populations, can be considered as the mean age of the HT Pampean metamorphism at the Sierras de Cordoba.