Estudio de Tomografía de Resistividad Eléctrica en estructuras de los Andes Nordpatagónicos

BRAN, DONALDO MAURICIO; LOZANO, JORGE GABRIEL; TASSONE, ALEJANDRO; ALMARÁZ, FERNANDO; VILLAROSA, GUSTAVO; VILAS, JUAN FRANCISCO

San Miguel de Tucumán

Congreso; XX Congreso Geológico Argentino; 2017

AGA

This work deals with the results of a Resistivity Tomography (ERT) survey,carried out in the northern sector of the Norpatagonian Andes in order toinvestigate the subsurface continuity and geometric features of the Catedraland Pantanoso faults and some morphological lineaments. Resistivity profileswere measured using a 48 channel Syscal R1 switch. The equidistance betweenelectrodes was 10 meters and the chosen array was the Wenner-Schlumberger,resulting in a penetration depth of approximately 70 meters. The inversion ofresistivity data was achieved with the Res2DInv software of Geotomo SoftwareInc. The geophysical data was constrained with the analysis of outcropmeasurements. The Catedral fault ERT showed a zone of relative low resistivitythat correlates with an outcropping consolidated breccia, where several northwesttrending fault planes with inverse kinematics and medium to high inclinations weremeasured. Consequently, the Catedral fault could be characterized as a highangle fault zone of 100 meters width. The Pantanoso thrust ERT revealed aflexured low resistivity strip that was associated with an inverse structurebut, in this case, with a gentle dip to the southwest. This interpreted faultplane is truncated by a high resistivity wedge, attributed to the alluvialdeposits that cover the surveyed area. On the other hand, the resistivityprofiles across the northeast trending lineaments gave results that supporttheir structural character, being controlled by the activity of faults withnormal displacements. In addition, resistivity ranges were obtained for severallithological units of the area on the basis of outcrop correlation.