Aplicação do método magnetotelúrico na porção central da Bacia do Paraná: imageamento das principais estruturas e intrusões ígneas

Abstract

The study discusses the application of the magnetotelluric (MT) method in the central portion of the Paraná Basin, utilizing three regional profiles. This area is characterized by the thickest section of the Serra Geral Formation and a substantial sedimentary sequence structured by multiple tectonic orientations (NE-SW and NW-SE), resulting from the stress responses at the basin’s boundaries. The study aims to define a resistivity model, derived from the application of the MT method, that aligns with the structural and lithostratigraphic aspects of the area's geology. This model enables the extraction of new information along seismic profiles that fail to produce effective results due to extensive basaltic occurrences. The analysis was conducted through the interpretation of results in pseudo sections and the inversion of 1D and 2D models, generating an initial interpretation based on the resistivity model. The integration of geophysical method responses with well data enhanced the understanding of the region’s major structural and lithostratigraphic units. Furthermore, correlating this interpretation with seismic signatures revealed stronger relationships between the fault zones of Curitiba-Maringá, Rio Alonso, São Jerônimo-Curiúva, and Santo Anastácio and the igneous intrusions associated with the Ponta Grossa Arch. The intrusions related to the Serra Geral Formation exhibit a strong correlation with these NW-SE structures in the region. The application of the magnetotelluric method, combined with joint interpretation, provided a high-resolution image of the Paraná Basin’s main structures, including the dikes and sills of the Serra Geral Formation. Additionally, it enabled the correlation of resistivity with key lithostratigraphic units and the delineation of the basement top.