FOLLOWING THE STEPS OF CHI-PA

RENATA TOMEZZOLI; JUAN MARTÍN CALVAGNO; JULIA OCHOA; HUGO TICKYJ; LEANDRO GALLO; JUAN BATTLER; MARÍA BELÉN FEBBO; FEDERICO COPERNITI

Rancagua

Congreso; 6° Reunión Bienal de la Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo (LATINMAG); 2019

Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo

The geological evolution of the southwest Gondwana margin is still a subject of debate. Here anisotropy of magnetic susceptibility and paleomagnetism results from different localities along this margin are presented. Samples from Buenos Aires, La Pampa and Mendoza provinces in Argentina were analysed. In the rocks of Permian age, there is a clear regional magnetic signature indicating a NW-SE elongation direction and a NE-SW shortening. However, the AMS patterns obtained in the oldest rocks with Middle Devonian to the Permian ages are complex, as the result of stress interference and overlap of orogenic activities with pulses of different magnitudes that deferred in the space and time. The deformation that began in medium to upper Devonian (Chañica orogenic phase in Argentina) is related to the collision of Chilenia from the west and Patagonia from the south-southwest with Gondwana, respectively. This deformation continued until the Permian (San Rafael orogenic phase in Argentina) as post-colisional compressive deformation, consequence of the paleogeographic re-organization of Gondwana (Laurentia) that moves to the Equator from the south (north) to form the Pangea continent during the Triassic. Since Chilenia and Patagonia collided against Gondwana at the same time, have been proposed the possibility that were the same alloctonous plate: CHIPA.