Abstract

ALICIA, Favetto  and  POMPOSIELLO, Cristina. Geoelectric modeling of the Chacoparanense Basin in Santa Fe-Entre Ríos from a magnetotelluric study. Rev. Asoc. Geol. Argent. [online]. 2010, vol.67, n.1, pp.130-138. ISSN 0004-4822.

The magnetotelluric data analyzed in this study correspond to the west-east regional-scale profile at 31.5ºS registered between 2001 and 2008. This profile extends from its western end at San Juan province to the eastern part of Entre Ríos province near the Uruguay river. Data interpretation of twenty two sites corresponding to the most eastern part of this profile was used to image the geoelectrical features of the inner earth. This study allowed finding an electrical resistivity model, resolving the crystalline basement geometry within this sector of the Chacoparanense basin. It was quantitatively determined that the dimensionality of the dominant conducting structures is approximately 1D up to the first 10 seconds and 2D for longer periods. The multisite regional strike determination resulted in an angle of N6ºE. The sedimentary basin model shows that the deepest part is located in the center, around 4 km deep, and at both ends the basin extends down to lower depths of around 3 km. The resistivity of the sediments observed within the basin is very low, from less than 1 Ωm up to 10 Ωm. These results are consistent with to the extremely low resistivities found in the hydrothermal well, Villaguay, due to its high salinity water.

Keywords : Magnetoteluric; Sedimentary basin; Entre Ríos.

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