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

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Yanne da Silva Queiroz ; Gláucia Queiroga ; Renato de Moraes ; Victor Matheus Tavares Fernandes ; Edgar Medeiros-Júnior ; Hanna Jordt-Evangelista ; Bernhard Schulz ; Julia Schmiedel ; Maximiliano Martins ; Marco Paulo de Castro ; Cristiano Lana

• Tipo de documento: Artigo Científico
• Fonte: BRAZILIAN JOURNAL OF GEOLOGY; v. 49, n. 3, p. -, 2019.
• Citações Web of Science: 0

Resumo

ABSTRACT 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. (AU)

• Processo FAPESP: 16/22627-3 - Metamorfismo e fusão parcial em Orógenos antigos II
• Beneficiário: Renato de Moraes
• Linha de fomento: Auxílio à Pesquisa - Regular