Estudio de la fábrica magnética en la Formación Lolén y su integración en un modelo de evolución de la deformación paleozoica a lo largo del margen sudoccidental del Gondwana durante el Paleozoico Superior.

TOMEZZOLI, R.N.; ARZADÚN, G; CRISTALLINI, E.O.; TICKYJ, H.; GALLO, L.C.; OCHOA, M.J.; BATTLER, J.M.

S.M. de Tucumán

Congreso; Simposio de Tectónica Pre-Andina. XX Congreso Geológico Argentino; 2017

Asociación Geológica Argentina

The Lolén Formation, of devonian age, outcrops in the Sierras Australes area of the Buenos Aires Province. Paleomagnetic and anisotropy of magnetic susceptibility (ASM) studies were carry out inside the Las Acacias farm (38° 04.2´ S, 61° 52.7? W). Its results are integrated with others obtained along the Southwest Gondwana margin from the Sierras Australes to the Agua Escondida places. The geological evolution of this region is still a subject of debate.Rocks of different lithologies and ages ranging from Late Devonian to Permian-Triassic were studied. Each place has its own magnetic signature, with a gradual development in the tectonic expression of ASM within and between them. For rocks of Permian age there is a clear regional magnetic signature indicating an NW-SE elongation direction and NE-SW shortening. However, the ASM patterns obtained in the oldest rocks are complex, probably as the results of stress interference in the magnitudes, space and time with different pulses of the orogenic activity. This deformation have been related with the collision of Chilenia and Patagonia with Gondwana during the Middle Devonian (Cháñica orogenic phase) and accommodating the postcolisional compressive deformation up to the Permian (San Rafael orogenic phase) with latitudinal and longitudinal movements.