Caracterização de rochas de alto grau metamórfico da Faixa Brasília meridional, Cascalho Rico - MG

Abstract

The region of Cascalho Rico­MG, located in the Internal Zone of the Southern Brasília Belt, South­Southeast of the Tocantins Province, contains a lithotectonic association characterized by subordinate muscovite schists (Araxá Group), followed by and orthogneisses and migmatites (Ortogneisse Goiandira) and granites (Suite Estrela do Sul granite), characterizing a high metamorphic terrain. The deformation phases that determined the configuration shown on the geological map of the region (Folha Estrela do Sul; SE.23­Y­AIV) are still unclear, and a detailed scale mapping (1:25,000) is fundamental to allow understandment of tectonic­metamorphic events in the region. Thus, this research aimed to characterize the associated granitoids and gneisses with the evolution of the high­grade metamorphic terrain in the region of Cascalho Rico­MG. The mapping resulted in the identification of six lithostratigraphic units described as Migmatitic Unit, Gneissic Unit, Granitic Unit, Mylonitic Unit and Sedimentary Unit. Making it possible to associate and allocate the units mentioned above as Araxá Group and as the Orthogneissic and Migmatitic Association Rocks. This work also resulted in the identification of a strong low­grade retrometamorphic event characterized by albitization of quartz­feldspathic rocks and sericitization of schits.