Análise estrutural das zonas de cisalhamento limeira e curiango na região entre Cascalho Rico (MG) e Araguari (MG), faixa Brasília Meridional

Abstract

This study investigates the dynamics of shear zones in the Cascalho Rico and Araguari regions (Minas Gerais, Brazil), focusing on the structural characterization of a possible tectonic contact between the Araxá Group and the Orthogneiss and Granulite Belt, within the Southern Brasília Belt. Shear zones concentrate crustal deformation and are often linked to significant tectonic displacements. The methodology combined literature review, cartographic base development, and structural analysis integrating remote sensing, gamma spectrometry, magnetometry, fieldwork, and petrography. Satellite images and geophysical data revealed NW-SE-trending lineaments and six radiometric domains enriched in K, U, and Th, reflecting lithological variations. Field observations identified features typical of strike-slip shear zones, such as mylonitic foliations, S-C structures, asymmetric porphyroclasts, and mica-fish, suggesting simple shear with rotational and flattening components. Evidence of compressional regimes, including isoclinal and tight folds with foliation overprints, was also documented. Structural interpretation indicates progressive evolution under a dextral transpressional regime, with reactivation and overprinting of earlier structures. The integrated data allowed the delimitation of major shear zones, such as the Limeira and Curiango zones, and their role in accommodating orogenic deformation. These results contribute to the understanding of the geodynamic evolution of the Southern Brasília Belt and the significance of shear zones in deep crustal processes.