| Texto completo | |
| Autor(es): |
Motta, Rafael G.
;
Moraes, Renato
;
Fitzsimons, Ian C. W.
;
Vilalva, Frederico Castro Jobim
;
Barros, Renata Ferreira
;
Souza, Zorano Sergio
;
Marimon, Rodrigo Schwantes
Número total de Autores: 7
|
| Tipo de documento: | Artigo Científico |
| Fonte: | LITHOS; v. 522, p. 14-pg., 2026-02-01. |
| Resumo | |
A large section of the continental lower crust is exposed in the southernmost Brasilia Orogen, Brazil, where rocks in the Guaxupe Domain experienced ultra-high temperature (UHT) metamorphism. These metamorphic rocks are dominated by felsic granulites and migmatites and exhibit a prolonged history of melt crystallization between 630 and 595 Ma, during which several granitic bodies, including charnockites, were emplaced. Two newly identified charnockite intrusions outcrop in the eastern part of the domain, displaying similarities with the previously described Divinolandia Suite. The data collected in this study, combined with previous research, indicate that charnockitic magmatism was coeval with the metamorphic peak. The isotopic signatures of Nd and Sr in whole rock, along with Hf in zircon suggest derivation from crustal sources with a long crustal residence history. Metamorphic modelling of felsic granulites shows that garnet and K-feldspar served as reactant phases during melt-producing reactions, and a significant amount of zircon was dissolved at peak metamorphic conditions, whereas plagioclase and orthopyroxene became concentrated in the residual granulite. The resulting partial melt would have been enriched in elements such as Fe, Mg, K, Rb, Ba, Zr, and Hf, but depleted in Ca and Sr, a pattern that matches the geochemistry of the charnockites. Thus, the charnockite magmatism was likely generated by the migration and crystallization of partial melts derived predominantly from felsic granulites and subordinately from other ancient sources. (AU) | |
| Processo FAPESP: | 16/22627-3 - Metamorfismo e fusão parcial em Orógenos antigos II |
| Beneficiário: | Renato de Moraes |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 16/10276-1 - Formação, Transformação e Evolução da Crosta Continental Inferior: Investigando o Orógeno Brasília Meridional |
| Beneficiário: | RAFAEL GONÇALVES DA MOTTA |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |
| Processo FAPESP: | 15/22355-0 - Formação, transformação e evolução da crosta continental inferior: investigando o orógeno brasília meridional |
| Beneficiário: | RAFAEL GONÇALVES DA MOTTA |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 13/04007-0 - Metamorfismo e fusão parcial em orógenos antigos |
| Beneficiário: | Renato de Moraes |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |