Structural evolution of the internal domain of the Southern Brasilia belt in Estrela do Sul, Minas Gerais, Brazil

Structural evolution of the internal domain of the Southern Brasília Belt in Estrela do Sul, Minas Gerais, Brazil

Abstract

The internal domain of the southern Brasilia Belt, in Estrela do Sul comprises Eastern Goiandira, Western Goiandira units, Monte Carmelo complex and Araxá Group. The region presents two structural domains with distinct evolution stages: Southwest (SW) Domain and Northeast (NE) Domain. The first one revealed the presence of four deformation phases (D1, D2, D3 and D4). High angle foliation (S2) dipping to SW associated with a sub-horizontal N-S mineral lineation (L2) characterized the phase (D2). The next phases D3 and D4 deformed S2 foliation and D3 phase is responsible for the regional structural framework. Besides that the developing of a low-angle foliation (S3), dipping to south, associated to E-W mineral lineation (L3) it is also associated with the D3 phase. The other domain (NE) shows similarity with D3 structures of the SW Domain presenting low-angle foliation associated with E-W trending low-plunging mineral lineation. However, high-angle foliation were not found. These features imply an associated tectonic evolution between SW and NE domain from D3 phase. In the SW domain the mineral paragenesis from Araxá Group and Goiandira orthogneiss indicate a amphibolite-facies metamorphism. This event is associated with D2 phase and have been identified two metamorphic zones staurolite and sillimanite zones.