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 Brasília Belt, in the Estrela do Sul region comprises Eastern Goiandira, Western Goiandira units, Monte Carmelo complex and Araxá Group. The region encompasses two structural domains with distinct evolution stages: Southwest (SW) Domain and Northeast (NE) Domain. The SW Domain is characterized by four tectonic phases (D1, D2, D3 and D4). High angle foliation (S2) dipping to SW associated with a sub-horizontal N-S mineral lineation (L2) characterize the phase (D2). 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 NE domain 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 similar to S2 in SW domain, were not found in NE domain. These features imply that the juxtaposition of the SE and NE domains occurred during the D3 phase. In the SW domain, the Araxá Group and Goiandira orthogneiss exhibit metamorphic parageneses of amphibolite facies. This metamorphic parageneses are associated with D2 phase and two metamorphic zones were identified: staurolite and sillimanite.