IDADES U-Pb POR ICP-MS EM ZIRCÃO DA PORÇÃO ORIENTAL DO CINTURÃO MINEIRO, MINAS GERAIS, E REGISTROS DE MAGMATISMO RELACIONADO AO CINTURÃO BRASILIA: U-Pb ages by  ICP-MS in zircon from the eastern portion of the Mineiro Belt, Minas Gerais, and records of t he magmatism related to the Brasilia Belt

Wagner Travassos LEMOS; Mauro César GERALDES; Marcelo dos Santos SALOMÃO; André Campos Rocha PINTO; Felippe Amaral de SOUZA; Rafael Cardoso de Moraes TELLES; Luís Felipe Romero da SILVA; Marco Helênio de Paula Alves COELHO; Marco Silva MACHADO; Armando Dias TAVARES

Authors

Wagner Travassos LEMOS Universidade do Estado do Rio de Janeiro
Mauro César GERALDES Universidade de Estado do Rio de Janeiro
Marcelo dos Santos SALOMÃO Universidade de Estado do Rio de Janeiro
André Campos Rocha PINTO Universidade de Estado do Rio de Janeiro
Felippe Amaral de SOUZA Universidade de Estado do Rio de Janeiro
Rafael Cardoso de Moraes TELLES Universidade de Estado do Rio de Janeiro
Luís Felipe Romero da SILVA
Marco Helênio de Paula Alves COELHO Universidade de Estado do Rio de Janeiro
Marco Silva MACHADO Universidade de Estado do Rio de Janeiro
Armando Dias TAVARES Universidade de Estado do Rio de Janeiro

Abstract

The Mineiro Belt was defined as a paleoproterozoic orogeny on the southeastern of the São Francisco Craton, which includes rocks of granitic, tonalitic, trondhjemitic, granodioritic and metamafic/ultramafic composition. These lithotypes are divided into three units: archean basement, paleoproterozoic granitoids and neoproterozoic magmatic suite. The main units of the present work are the Cupim granite, Caatinga gneiss, Chuí tonalite, Senhora dos Remédios quartzodiorite and the two new units proposed here, an archean metatrondhjemite named Chiquinha, and a neoproterozoic granodiorite named Menina Mineira. The studies included new U-Pb ages of these lithotypes, supported by a petrographic characterization, through the application of the LA-ICP-MS method. The Campinho Granite was classified as a monzogranite and presented an age of 2998±27Ma. The Chiquinha metatrondjemite gave an age of 2766±16Ma. Analyses of the Cupim granite produced an age of 2088±22Ma. The Chuí tonalite gave an age of 2087±11Ma. The Caatinga Gneiss gave ages between 2108±11Ma and 2135±11Ma, and the Menina Mineira granodiorite gave an age of 625.2±4.4Ma. The youngest magmatic event may be the result of crustal melting and/or mantle extraction during the amalgamation of Gondwana, with magmatism related to the Brasilia Orogeny.