Resultados paleomagnéticos preliminares en las sedimentitas neopaleozoicas de la Formación El Imperial, Bloque de San Rafael, Mendoza, Argentina

TOMEZZOLI, R.N., Y JAPAS, M.S.,

REVISTA DE LA ASOCIACION GEOLOGICA ARGENTINA

Asociación Geológica Argentina

Lugar: Buenos Aires; Año: 2006 vol. 61 p. 370 - 382

0004-4822

During the Early Permian an extensive deformation belt well-known as "Gondwánides" developed in the Southwest Gondwana margin. A foreland basin has been settled during the Late Carboniferous – Early Permian in the western end of this strip, and is represented by the El Imperial Formation, which crops out in the San Rafael Block. The upper section of this unit records an inversion of the ancient slopes, which has been interpreted as the first evidence of the migration of the orogenic front towards the foreland. Therefore, a paleomagnetic study has been carried out on this unit, searching for elements that allow to constraint the deformation age to evaluate the possible diachronism of it. First paleomagnetic results obtained in El Imperial Formation, from the lower member in the Represa Agua del Toro and from the upper member in the Puesto La Josefa, are presented and discussed. These rocks have reverse magnetizations carried by hematite, of possible Permian age. Pole positions are discordant with the apparent polar wander path from South America. These differences could be explained because: secular variation was not properly averaged; rotations about vertical axes of the sampling localities; or the combination of some or all these factors.