Structural analysis on the central Rio das Velhas greenstone belt, quadrilátero ferrífero (MG, Brazil)

Abstract

The Rio das Velhas Greenstone Belt (Quadrilátero Ferrífero, Brazil) study area has been divided in two structural domains: frontal and oblique ramps. The frontal ramp domain shows predominately oblate shape fabrics and larger dispersion of strain ellipsoids orientation, while strain is higher and fabrics are prolate on the oblique ramp domain. The observed fabrics were generated by superimposed deformations. E-W thrusting has modified and reoriented early fabrics formed during the Archean deformation event and/or the Bação Complex uplift. Basement highs in the lateral ramp domain generated higher internal deformation and local shortening, normal to the thrust's movement, originating prolate fabrics Variations of the shape fabric orientation on the frontal ramp domain reflect lower deformation values.