Geochronology and geochemistry of the Tabaquito batholith (Frontal Cordillera, Argentina): geodynamic implications and temporal correlations in the SW Gondwana margin

MORENO, JUAN A.; DAHLQUIST, JUAN A.; MORALES CÁMERA, MATÍAS M.; ALASINO, PABLO H.; LARROVERE, MARIANO A.; BASEI, MIGUEL A. S.; GALINDO, CARMEN; ZANDOMENI, PRISCILA S.; ROCHER, SEBASTIAN

JOURNAL OF THE GEOLOGICAL SOCIETY

GEOLOGICAL SOC PUBL HOUSE

Año: 2020 vol. 177 p. 455 - 474

0016-7649

The Tabaquito batholith (Frontal Cordillera, western Argentina), is mainly composed of shallowly emplacedgranodiorite to minor monzogranite with abundant mafic microgranular enclaves. New sensitive high-resolution ionmicroprobe U?Pb zircon ages of c. 337 Ma (biotite granodiorite) and c. 284 Ma (mafic dyke) along with previously publishedgeochronological data suggest that a long-lived magmatic system formed through at least two magmatic pulses at c. 337 and c.322 Ma with later superimposition of Permian magmatism. The Tabaquito granitoids are metaluminous, calc-alkalic andmagnesian with I-type affinity. Elevated Th/Nb, Y/Nb and La/Nb ratios along with negative Nb?Ta and positive Pb anomaliesare consistent with a continental arc setting. Hf, Nd and Sr isotopic composition of the Tabaquito granitoids suggests that theirsource could result from mixing of an old felsic crustal component and a juvenile mafic to intermediate component. Newgeochronological and geochemical data together with published data reveal a continuous arc setting from the Carboniferous tothe Permian in Argentina, and important magmatic compositional variations through time and space controlled by episodicfluctuations in the subduction angle of the oceanic plate. Reported and compiled data allow us to infer the continuity of theCarboniferous magmatic arc along the west margin of Gondwana.