Structural and Compositional Evolution of Cr-Spinels and Hornblends, Palma Group, Rio Grande do Sul, Brasil

Autores

  • LÉO AFRANEO HARTMANN Universidade Federal do Rio Grande do Sul/ Instituto de Geociências
  • MARCOS ANTONIO VASCONCELLOS Universidade Federal do Rio Grande do Sul/ Instituto de Física
  • MARIA DE FÁTIMA BITTENCOURT Universidade Federal do Rio Grando do Sul/ Instituto de Geociências
  • JOÃO CASTRO Universidade Federal do Rio Grande do Sul/ Instituto de Geociências
  • JULIANA FABIÃO Universidade Federal do Rio Grande do Sul/ Instituto de Geociências
  • ANDRÉIA MONTEIRO Universidade Federal do Rio Grande do Sul/ Instituto de Geociências
  • KAREN PIRES Universidade Federal do Rio Grande do Sul/ Instituto de Geociências

DOI:

https://doi.org/10.22456/1807-9806.20175

Palavras-chave:

Cr-spinels, hornblende, electron microprobe, backscattered electron.

Resumo

One amphibolite facies metamorphic event is registered in chromites and hornblendes from the Palma Group serpentinites and meta-andesites, Brazil's southernmost Rio Grande do Sui Slate. Metamorphism was apparently caused by syntectonic injection of voluminous Cambaí Group meta-granitoids and not by post-tectonic Jaguari Granite intrusion. Regional metamorphic hornblendes are in direct contact with magmatic pargasites, which indicates that it was the first metamorphic event in the area. Both hornblendes in Campestre Formation and Crspinels in Cerro da Cruz Formation are little zoned, an indication that only one metamorphic event was of regional extent. Recrystallization to chlorite + epidote greenschist facies parageneses is restricted to shear zones and volumetrically small.


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Publicado

2000-06-30

Como Citar

HARTMANN, L. A., VASCONCELLOS, M. A., BITTENCOURT, M. D. F., CASTRO, J., FABIÃO, J., MONTEIRO, A., & PIRES, K. (2000). Structural and Compositional Evolution of Cr-Spinels and Hornblends, Palma Group, Rio Grande do Sul, Brasil. Pesquisas Em Geociências, 27(1), 15–27. https://doi.org/10.22456/1807-9806.20175