Caracterização estrutural da zona de cisalhamento Douradinho na região entre Coromandel/MG e Abadia dos Dourados/MG

Abstract

This Bachelor's Thesis aimed to characterize the Douradinho Shear Zone, a regional deformation zone with a preferential NW–SE trend, located between the municipalities of Coromandel and Abadia dos Dourados, Minas Gerais, Brazil. The structure affects rocks of the Monte Carmelo Complex, Abadia dos Dourados Complex, and Araxá Group, constituting a structurally significant feature within the southern portion of the Brasília Belt. A multiscale approach was employed based on the integration of morphostructural, airborne geophysical, field geological, microstructural, and three-dimensional geological modeling data. The analysis of Digital Elevation Models (DEM), combined with the interpretation of gamma-ray spectrometric and magnetic data, revealed a strong NW–SE structural control over the relief and drainage network, evidenced by rectilinear channel segments and fluvial deflection anomalies. Geophysical products revealed radiometric and magnetic contrasts associated with the different geological units, indicating that the granitic bodies acted as relatively more competent domains during regional deformation, promoting strain partitioning along their margins. Three-dimensional geological modeling demonstrated the spatial continuity of these structures at depth and enabled the correlation between geophysical domains and surface observations. Petrographic and microstructural analyses identified intracrystalline deformation features and dynamic recrystallization in quartz, associated with the predominantly brittle behavior of feldspars, indicating deformation under low-grade greenschist facies metamorphic conditions. Furthermore, the observed mineral assemblage suggests that the structure acted as a conduit for the circulation of fluids. Although no diagnostic kinematic indicators were identified to unequivocally determine the sense of movement of the structure, the integration of the different datasets allowed the characterization of the spatial distribution of deformation and the role played by the Douradinho Shear Zone in the lithostructural arrangement of the local geological units. The results contribute to the understanding of the structural evolution of the southern portion of the Brasília Belt and provide a basis for future tectonic and geophysical investigations in the region.