VARIACIONES DE LA ANISOTROPÍA DE SUSCEPTIBILIDAD MAGNÉTICA (ASM) A LO LARGO DEL MARGEN SUROCCIDENTAL DEL GONDWANA

TOMEZZOLI R.N.; CRISTALLINI, E.O.

Rio de Janeiro

Simposio; VII Reunión Bienal de la Asociación Latinoamericana de Paleomagnetismo; 2023

Latinmag

Geological evidence indicates that deformation along the southwestern Gondwana´s margin began during the Middle Devonian (Cháñica orogenic phase in Argentina – Acadian) and continued until the Permian. We interpret that the beginning of this deformation is related to the collision of Chilenia to the west and Patagonia to the south-southwest. Since Chilenia and Patagonia collided at the same time against Gondwana, we proposed that they formed the same allochthonous terrane referred to as CHIPA. This margin can be assimilated as a fold and thrust belt (FTB) from the Sierras Australes to the Bloque de San Rafael. Field work, paleomagnetic and anisotropy of magnetic susceptibility studies (AMS) were integrated from different locations of this paleomargin. The sites examined within the northeast sector of this FTB present a magnetic fabric with its Kmin axes inclined towards the northeast. On the contrary, the sites located southwest of the FTB have the Kmin axes inclined towards the southwest. Assuming that the Kmin axis of AMS is subparallel to the maximum principal stress (Sigma 1), it is interpreted that this arrangement of the AMS axes is related to the stress distribution in a this FTB formed during the late Paleozoic.