INGEIS   05370
INSTITUTO DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA
Unidad Ejecutora - UE
artículos
Título:
2D Magnetotelluric interpretation of the crust electrical resistivity across the
Autor/es:
FAVETTO ALICIA; POMPOSIELLO CRISTINA; MÓNICA G. LÓPEZ DE LUCHI; JOHN BOOKER
Revista:
TECTONOPHYSICS
Editorial:
ELSEVIER
Referencias:
Año: 2007
ISSN:
0040-1951
Resumen:
Magnetotelluric data were obtained along a 450 km, almost west-east profile at approximately 31.5º S, which extends from La Rioja to Santa Fé provinces in central Argentina. The profile crosses two main crustal domains that were juxtaposed during the Early-Middle Cambrian Pampean Orogeny: the Pampean terrane to the west and the Río de la Plata craton to the east. The electrical resistivity structure of the crustal domains together with their boundary is presented. Through dimensionality analysis of the data, it was demonstrated that regional-scale electrical structures are mainly two-dimensional with a strike direction oriented parallel to the surface geological strike. The resistivity model shows a subvertical limit approximately along the eastern border of the Sierra Chica de Córdoba. To the east, the shallower structure is the Chaco-Paranense basin extending to a depth of 6 km with resistivities between 1 and 30 ohm-m, whereas below the basin the ca 2.1-2.3 Ga Río de la Plata craton shows resistivities in a range of 300-10000 ohm-m. The Pampean terrane presents a 6 km layer with a resistivity higher than 10000 ohm-m whereas below this layer the resistivity values range from 50 to 200 ohm-m. Based on both the geological information and the magnetotelluric results, the sharp lateral discontinuity observed in the resistivity model to the east of the Sierras de Córdoba is conjectured to represent the boundary between the Río de la Plata craton and the Pampean terrane which may correspond to the Early Cambrian suture. Keywords: Suture, Sierras de Córdoba, Sierras Pampeanas, Magnetotellurics, Electrical resistivity.