A TECTÔNICA EXTENSIONAL PALEOPROTEROZÓICA NA BORDA SUDESTE DO CRATON SÃO FRANCISCO (SE, BRASIL): GEOQUÍMICA E PETROLOGIA DAS METAÍGNEAS.

Abstract

This work presents an assembly of geological, geochemical and petrological data concerning differentepisodes of magmatism related to Espinhaço Basin evolution in the central part of Minas Gerais State, witha goal to understand aspects of paleoproterozoic crust and tensional tectonic. Metamagmatic rocks arerepresented by alkaline flows, tholeitic gabbros and basalts and subalkaline granites and rhyolites. Geologicaland geochemical data indicate magma genesis in an anorogenic context at about 1.7 Ga. Taken together, allthese magmatic episodes reflect great rigidity of the Paleoproterozoic continental crust and indicate thatmagma genesis process occurred whenever there was a resurgence of crustal extension, fracturing andrifting, deep melting and the provision of conduits for the mantle heat and mantle magmas to rise into andmelt the crust.