ESTUDIO PETROGENÉTICO DEL BATOLITO TABAQUITO: UN EJEMPLO DEL MAGMATISMO PRE-ANDINO CARBONÍFERO

MORENO, J.A.; DAHLQUIST, J.; MORALES CÁMERA, M.M.; ALASINO, P.H.; LARROVERE, M.; BASEI, M.A.S.; GALINDO, C.; ZANDOMENI, P.; ROCHER, S.

Córdoba

Congreso; XIII CONGRESO DE MINERALOGÍA, PETROLOGÍA ÍGNEA Y METAMÓRFICA, Y METALOGÉNESIS; 2019

Asociación Geológica Argentina y Asociación de Mineralogía de Argentina

Petrogenetic study of the Tabaquito batholith: an example of the Carboniferous pre-Andean magmatism. The Tabaquito batholith (Frontal Cordillera, western Argentina), is mainly made of shallow emplaced granodiorite to minor monzogranite with common presence of mafic microgranular enclaves. New SHRIMP U?Pb zircon ages of ∼337 Ma (biotite granodiorite) and ∼284 Ma (mafic dike) and reprocessing of previous geochronological data (317 Ma; Dahlquist et al., 2018) suggest a long-lived magmatic system formed through at least two magmatic pulses at ∼337 Ma and ∼317 Ma with later superposition of Permian magmatism. The Tabaquito granitoids are metaluminous, calc-alkalic and magnesian with I-type affinity. Elevated Th/Nb, Y/Nb and La/Nb ratios along with negative Nb-Ta and positive Pb anomalies are consistent with a continental arc setting. Hf (εHf range ?2.0 to +4.5), Nd (εNdi: −1.6 to −2.4) and Sr (Sr/Sri = 0.7053−0.7056) isotopic composition of these rocks suggests their source could result from mixing of an old felsic crustal component and a juvenile mafic to intermediate component.These data reveal that the Andean magmatic cycle can be extended to the Carboniferous with the arc magmatism being continuous to the present, but with an important compositional variation through time and space controlled by episodic fluctuations in the subduction angle of the oceanic plate.