Relaciones estratigráficas de volcanitas del Choiyoi Inferior sobre la base de estudios paleomagnéticos, Bloque de San Rafael, Mendoza, Argentina.

TOMEZZOLI, R.N., L. KLEIMAN, J. SALVARREDI, C.TERRIZZANO AND E.O. CRISTALLINI

Buenos Aires

Congreso; XVI Congreso Geológico Argentino; 2005

  Work is in progress on the Permian-Triassic section of South-Central Argentina along a zone believed to be the Devonian collision of Patagonia with South America known as "SamFrau geosyncline". In order to improve knowledge of this part of Gondwana and to explore regional relationships between sedimentation, volcanism and age of deformation, new studies involve rocks from the San Rafael block deformed during the late Paleozoic, in the Province of Mendoza, Argentina. This collision model is still uncertain and there are many controversies related to the age of the deformation of this belt. Gondwana magmatism in the study area, is represented by the Choiyoi magmatic province which can be divided into a lower sequence and an upper sequence. The Choiyoi lower sequence contains at least seven cooling units of an ignimbrite which deposited in two N-S trending troughs known as the eastern and western basins. New paleomagnetic data of these volcanics allowed the calculation of paleomagnetic poles for the Early Permian.These data was useful also to show some relationships among the different ignimbrite cooling units in both basins. For instance, samples believed to correspond to the same unit, showed a different direction of the paleomagnetic field in the western basin.