Pseudosection modeling and U-Pb geochronology on Piranga schists : role of Brasiliano Orogeny in the Southeastern Quadrilátero Ferrífero, Minas Gerais, Brazil.

In the Southeastern Quadrilátero Ferrífero, a package of metapelitic rocks previously attributed to the Archean Rio das Velhas Supergroup crops out in Piranga locality. This study presents the mineral chemistry and U-Pb-Hf zircon geochronology on foliated staurolite-garnet mica schists. Garnet and s...

ver descrição completa

Detalhes bibliográficos
Autores: Queiroz, Yanne da Silva, Queiroga, Gláucia Nascimento, Moraes, Renato de, Fernandes, Victor Matheus Tavares, Medeiros Júnior, Edgar Batista de, Evangelista, Hanna Jordt, Schulz, Bernhard, Schmiedel, Julia, Martins, Maximiliano de Souza, Castro, Marco Paulo de, Lana, Cristiano de Carvalho
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:Brasil
Recursos:Universidade Federal de Ouro Preto (UFOP)
Repositorio:Repositório Institucional da UFOP
Idioma:inglés
OAI Identifier:oai:repositorio.ufop.br:123456789/12053
Acesso em linha:http://www.repositorio.ufop.br/handle/123456789/12053
https://doi.org/10.1590/2317-4889201920180136 
Access Level:acceso abierto
Palavra-chave:São Francisco Craton
Pelitic rocks
U-Pb zircon and monazite geochronology
Lu-Hf isotopes
Descrição
Resumo:In the Southeastern Quadrilátero Ferrífero, a package of metapelitic rocks previously attributed to the Archean Rio das Velhas Supergroup crops out in Piranga locality. This study presents the mineral chemistry and U-Pb-Hf zircon geochronology on foliated staurolite-garnet mica schists. Garnet and staurolite index minerals are syn- to post-kinematic towards the main schistosity. Garnet porphyroblasts display well-developed compositional zoning of Mg-Fe-Mn-Ca, with increase of almandine and pyrope and decrease of spessartine towards the rim, implying in prograde metamorphic pattern. Estimates of P-T values for the metamorphic peak resulted in temperatures between 630 to 650ºC and pressure around 7 kbar. Pseudosections show well-defined stability fields in amphibolite facies, with a metamorphic path displaying progressive increase in P-T conditions. Maximum depositional age of 1,875 ± 51 Ma is established for the Piranga mica schists pointing to a depositional history that is younger than those previously described. Metamorphic Cambrian ages characterize the strong influence of deformational processes related to the final stages of Brasiliano Orogeny in the Southeastern Quadrilátero Ferrífero.

Registos relacionados