Caracterização geológica de uma anomalia magnética de direção NW com a integração de dados de magnetometria aérea e terrestre no Escudo Sul-rio-grandense

Abstract

Despite being the subject of numerous geological researches, some events that occurred in the evolution of the Sul-rio-grandense Shield are still a gap in the understanding of the development of this territorial portion in the state of Rio Grande do Sul. This is the case of northwest (NW) magnetic lineaments, which until today have been little mentioned in the literature. For different authors, these lineaments have their origin linked to the formation of the structural high of the Arch of Rio Grande, and even though these structures would have served as supposed feeder ducts of the volcanism that generated the Serra Geral Formation. This work aimed to study a portion of one of these magnetic lineaments. A very representative lineament was chosen, where other work had already been carried out by former students of the geology course at UNIPAMPA. Such studies focused on the petrography of the source body of the magnetic anomaly. The target lineament of this work is located in the northern portion of the municipality of Pinheiro Machado. In order to arrive at the expected results, geophysics data were used that allowed the analysis of the geological structure, the causative source of the magnetic anomaly, both on the surface and sub-surface. For this, a terrestrial magnetometric survey was carried out, which consisted in the acquisition of data in six profiles carried out perpendicularly to the length of the magnetic anomaly, magnetic susceptibility data of the outcropping rocks in the study area were also collected. Other magnetometry data used in this work were provided by the Geological Survey of Brazil (CPRM), from the Aerogeophysic Project Escudo of Rio Grande do Sul. With this, it was possible to delimit the lithological contacts of the body causing the magnetic anomaly in relation to its host rocks, to determine the type of geological structure and the geometry of the body.