Permo-triassic collision of Patagonia? Paleomagnetic evidence

RAPALINI, AUGUSTO E.; MIGUEZ, MAXIMILIANO; LUPPO, TOMÁS; LÓPEZ DE LUCHI, MÓNICA ; MARTÍNEZ DOPICO, CARMEN ; FANNING, C. MARK

Querétaro

Congreso; 5ta Reunion Bienal de Asociacion Latinoamericana de Paleomagnetismo y Geomagnetismo LATINMAG; 2017

Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo

Two paleomagnetic poles from magmatic rocks of the Permo-Triassic La Esperanza Plutono-Volcanic Complex in northern Patagonia show significantly different positions. A paleomagnetic study on the Collinao Dacite, dated as 253 Ma, yielded a pole that is anomalous with respect to the Gondwana Late Paleozoic apparent polar wander path, falling within the Late Carboniferous (340-300 Ma) reference poles. On the other hand, a pole computed for acidic dykes of 244 Ma is consistent with Early Triassic (250-240 Ma) reference poles for Gondwana. A model proposing a ca. 30° ccw rotation of the North Patagonian Massif in such lapse as final stages of collision of Patagonia against the Gondwana margin, closing a small V-shaped oceanic(?) basin, may explain the paleomagnetic evidence and is consistent with different geological evidence.