Geology and petrography of the Glória Quartz-Monzodiorite, Mineiro Belt, southern portion of the São Francisco Craton, Minas Gerais State ; Geologia e Petrografia do Quartzo Monzodiorito Glória, Cinturão Mineiro, Porção Sul do Cráton São Francisco, Estado de Minas Gerais

Mafic and felsic plutons of the Mineiro Belt occur nearby the Lavras and Conselheiro Lafaiete cities, in the southern portion of the São Francisco Craton. The Glória Quartz-Monzodiorite is a small mafic intrusion (9km2) emplaced into schists, metapelites, and amphibolites associated with the Rio das Mortes Greenstone Belt. This pluton bears ultramafic and amphibolite xenoliths, and is intruded by pegmatite and granitic dikes of the Ritápolis Granitoid. The Glória Quartz-Monzodiorite includes diorites, quartz- diorites, quartz-monzodiorites, and tonalites. These rocks are subdivided into three coeval granolumetric facies that may represent members of associated subalkaline series resulting from differentiation of a parental andesitic/dioritic liquid. The primary mineral assemblage of the Glória Quartz-Monzodiorite was overprinted by a greenschist metamorphic paragenesis composed of actinolite, albite, sphene, and epidote. Actinolite was further replaced by metassomatic biotite taken as derived from a potassic fluid influx associated with pegmatite and granitic dikes of the Ritápolis Granitoid. The metamorphic and metassomatic mineral assemblages of the Glória Quartz-Monzodiorite may have taken place in the 2.131 ± 4 Ma and 2.121 ± 7 Ma time range, according to available minimum ages from the crystallization of Brumado Diorite and Ritapolis Granitoid. Therefore, both processes are probably tectonically related with the Paleoproterozoic evolution of the Mineiro Belt. ; A região entre as cidades de Lavras e Conselheiro Lafaiete, na borda meridional do Cráton São Francisco, é caracterizada pela presença de diversos corpos plutônicos félsicos e máficos, que encontram-se relacionados à evolução paleoproterozóica do Cinturão Mineiro. Dentre os corpos máficos, destaca-se o Quartzo Monzodiorito Glória, que ocorre encaixado em anfibolitos e rochas metassedimentares da Faixa Greenstone Rio das Mortes. Este corpo apresenta enclaves de rochas metaultramáficas e anfibolitos, além de ser cortado por ...