CO GENETIC CR-TOURMALINE AND EMERALD IN THE NOVO CRUZEIRO PEGMATITE FIELD (MINAS GERAIS, BRAZIL)

Authors

  • Heinrich Adolf Horn http://orcid.org/0000-0002-2866-1471
  • Yves Fuchs Université Gustave Eiffel, Marne la Vallée, France
  • Chloe Fourdrin Université Gustave Eiffel, Marne la Vallée, France
  • Jean Marc Grenèche Université du Maine, Le Mans, France https://orcid.org/0000-0001-7309-8633
  • Omar Boudouma Université Sorbonne Nouvelle, Paris, France

DOI:

https://doi.org/10.21715/GB2358-2812.202236003

Keywords:

emeralds, Cr-tourmalines, co-genetic formation, pegmatite sources

Abstract

The Novo Cruzeiro pegmatite field in Minas Gerais (Brazil) between Téofilo Otoni and the Jequitinhonha River belongs to the areas of the EBPP with tourmaline and emerald occurrences. The pegmatites show beside of coloured tourmalines, Cr rich black tourmaline cogenetic with Cr-emerald. General crystallization conditions of the pegmatites are given with due to the obtained data, important changes during final phase of tourmaline crystallisation causing variations in tourmaline chemistry and reflect differences in the chemistry of the participating fluids. The deposition of tourmaline ceased and after a period of cocristallization, emerald was the only mineral that formed then. The obtained information suggests a crystallization sequence from tourmaline over tourmaline-emerald to emerald. A part of B and Fe may come from the host rock, Be and B also from the intrusive granites and Cr from regional mafic to ultramafic rocks like amphibolite or Bt-Qu-schist.

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Author Biographies

Heinrich Adolf Horn

Geological Department Professor Subchef

Yves Fuchs, Université Gustave Eiffel, Marne la Vallée, France

Laboratoire Géomatériaux et Environnement (LGE), Université Gustave Eiffel, Marne la Vallée, France.

Chloe Fourdrin, Université Gustave Eiffel, Marne la Vallée, France

Laboratoire Géomatériaux et Environnement (LGE), Université Gustave Eiffel, Marne la Vallée, France

Jean Marc Grenèche, Université du Maine, Le Mans, France

Institut molécules et matériaux, UMR 6283 of CNRS, Université du Maine, Le Mans, France

Omar Boudouma, Université Sorbonne Nouvelle, Paris, France

Institut des Sciences de la Terre de Paris (ISTP), UMR 7193, Université Sorbonne Nouvelle, Paris, France.

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Published

2022-03-21

How to Cite

Horn, H. A., Fuchs, Y., Fourdrin, C., Grenèche, J. M. ., & Boudouma, O. . (2022). CO GENETIC CR-TOURMALINE AND EMERALD IN THE NOVO CRUZEIRO PEGMATITE FIELD (MINAS GERAIS, BRAZIL). Geochimica Brasiliensis, 36, e–22003. https://doi.org/10.21715/GB2358-2812.202236003