PERMO-TRIASSIC COLLISION OF PATAGONIA? PALEOMAGNETIC EVIDENCE

LUPPO TOMAS; RAPALINI, A.E.; LOPEZ DE LUCHI, M.G.; MARTINEZ DOPICO, C.I.; MIGUEZ, M.; FANNING, M

LatinMag Letters

Universidad Nacional Autónoma de México

Lugar: Mexico Del. Coyoacán; Año: 2017 vol. 7 p. 1 - 5

2007-9656

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 Paleozoicapparent 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° counterclockwise (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.