ORDOVICIAN PERALUMINOUS GRANITES IN THE SIERRA DE PIE DE PALO, WESTERN SIERRAS PAMPEANAS OF ARGENTINA: GEOTECTONIC IMPLICATIONS

BALDO, E.G.; DAHLQUIST, J.A.; CASQUET , C.; RAPELA, C.W.; PANKHURST, R.J.; GALINDO, C.; FANNING, C.M.; RAMACCIOTTI, C.

Oviedo

Simposio; GEOLOGÍA DE LA CORDILLERA DE LOS ANDES Y SU ANTEPAÍS. Geology of the Andean Cordillera and its foreland.; 2012

Sociedad Geológica de España

Sills of garnet-biotite-muscovite peraluminous granite were injected into the upper part of the nappe stacking from the Sierra de Pie de Palo, formed during the Famatinian orogeny (Ordovician). Two studied granites yielded SHRIMP U-Pb zircon ages of 474 ± 6 Ma and 470 ± 10 Ma, indicating that they were largely coeval with thrusting. Structural similarities with Himalayan leucogranites injected into the upper part of the Greater Himalayan Sequence during India?Asia collision suggest a similar geotectonic scenario for the Famatinian granites. It is suggested that felsic magmas were generated at the root of the thrust plane, probably close to the Famatinian magmatic arc along the Western Gondwana margin.