Reconstrucción estructural de una sección de la Precordillera Occidental Argentina (31º08’ls-69º24’lo) a partir de datos aeromagnéticos

Abstract

The magnetic anomaly profile performed along the NE-SW (31º08’LS - 69º24’LO) structural section at the western edge of the Argentine Precordillera, is presented. By the application of ratios between bands, Landsat 7 ETM+ satellite images were processed as well as aeromagnetic data by filtering methods (reduction to the pole and calculation of the residual magnetic anomaly) and emphasized magnetic anomaly (analytical signal). Two lithofacies within the Don Polo Formation (lithofacies I at the base and II at the top of the sequence) were recognised. The main structure of Villa Corral mountain range is defined by a synclinal fold with a dipping axis to the SE and similar smaller-scale folds associated, which altogether are fragmented by two landslide systems: the Pre- Andean one, oriented NW-SE inclined fault planes to the NE and top-to-the SW motion; the other, Andean, with N-S direction and inclined fault plane to the W with top-to-the E motion. The analytical signal profile shows the importance of magnetic contrasts produced by major landslides that overlap clastic metasedimentary rocks of different stratigraphic levels intruded by seams of igneous acidic rock layers. Thus, magnetic methods allow adjusting the distribution of underground units according to the relative displacement of fault blocks.