Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UnB |
Texto Completo: | https://repositorio.unb.br/handle/10482/36684 https://doi.org/10.1590/2317-4889201920190081 http://orcid.org/0000-0003-0815-6790 http://orcid.org/0000-0002-4957-5951 http://orcid.org/0000-0002-7954-5059 http://orcid.org/0000-0002-0525-059X |
Resumo: | The Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma. |
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Santiago, Judiron SantosSouza, Valmir da SilvaDantas, Elton LuizOliveira, Claudinei Gouveia de2020-01-24T10:33:10Z2020-01-24T10:33:10Z2019SANTIAGO, Judiron Santos et al. Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit. Brazilian Journal of Geology, v. 49, n. 4, e20190081, 2019. DOI: https://doi.org/10.1590/2317-4889201920190081. Disponível em: http://scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303. Acesso em: 23 jan. 2020.https://repositorio.unb.br/handle/10482/36684https://doi.org/10.1590/2317-4889201920190081http://orcid.org/0000-0003-0815-6790http://orcid.org/0000-0002-4957-5951http://orcid.org/0000-0002-7954-5059http://orcid.org/0000-0002-0525-059XSociedade Brasileira de Geologia(CC BY) - The autors. This is an open access article distributed under the terms of the Creative Commons license.info:eu-repo/semantics/openAccessEdiacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim depositinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlePedras preciosas - minas e mineração - Brasil, NordesteGeologiaGeoquímicaGeocronologiaThe Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma.engreponame:Repositório Institucional da UnBinstname:Universidade de Brasília (UnB)instacron:UNBORIGINALARTIGO_EdiacaranEmeraldMineralization.pdfapplication/pdf13324066http://repositorio2.unb.br/jspui/bitstream/10482/36684/1/ARTIGO_EdiacaranEmeraldMineralization.pdf8359bff9a4b205c3ece75797d6ad8083MD51open access10482/366842023-05-26 21:23:05.133open accessoai:repositorio2.unb.br:10482/36684Biblioteca Digital de Teses e DissertaçõesPUBhttps://repositorio.unb.br/oai/requestopendoar:2023-05-27T00:23:05Repositório Institucional da UnB - Universidade de Brasília (UnB)false |
dc.title.pt_BR.fl_str_mv |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
title |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
spellingShingle |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit Santiago, Judiron Santos Pedras preciosas - minas e mineração - Brasil, Nordeste Geologia Geoquímica Geocronologia |
title_short |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
title_full |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
title_fullStr |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
title_full_unstemmed |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
title_sort |
Ediacaran emerald mineralization in Northeastern Brazil : the case of the Fazenda Bonfim deposit |
author |
Santiago, Judiron Santos |
author_facet |
Santiago, Judiron Santos Souza, Valmir da Silva Dantas, Elton Luiz Oliveira, Claudinei Gouveia de |
author_role |
author |
author2 |
Souza, Valmir da Silva Dantas, Elton Luiz Oliveira, Claudinei Gouveia de |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Santiago, Judiron Santos Souza, Valmir da Silva Dantas, Elton Luiz Oliveira, Claudinei Gouveia de |
dc.subject.keyword.pt_BR.fl_str_mv |
Pedras preciosas - minas e mineração - Brasil, Nordeste Geologia Geoquímica Geocronologia |
topic |
Pedras preciosas - minas e mineração - Brasil, Nordeste Geologia Geoquímica Geocronologia |
description |
The Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma. |
publishDate |
2019 |
dc.date.issued.fl_str_mv |
2019 |
dc.date.accessioned.fl_str_mv |
2020-01-24T10:33:10Z |
dc.date.available.fl_str_mv |
2020-01-24T10:33:10Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SANTIAGO, Judiron Santos et al. Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit. Brazilian Journal of Geology, v. 49, n. 4, e20190081, 2019. DOI: https://doi.org/10.1590/2317-4889201920190081. Disponível em: http://scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303. Acesso em: 23 jan. 2020. |
dc.identifier.uri.fl_str_mv |
https://repositorio.unb.br/handle/10482/36684 |
dc.identifier.doi.pt_BR.fl_str_mv |
https://doi.org/10.1590/2317-4889201920190081 |
dc.identifier.orcid.none.fl_str_mv |
http://orcid.org/0000-0003-0815-6790 http://orcid.org/0000-0002-4957-5951 http://orcid.org/0000-0002-7954-5059 http://orcid.org/0000-0002-0525-059X |
identifier_str_mv |
SANTIAGO, Judiron Santos et al. Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit. Brazilian Journal of Geology, v. 49, n. 4, e20190081, 2019. DOI: https://doi.org/10.1590/2317-4889201920190081. Disponível em: http://scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303. Acesso em: 23 jan. 2020. |
url |
https://repositorio.unb.br/handle/10482/36684 https://doi.org/10.1590/2317-4889201920190081 http://orcid.org/0000-0003-0815-6790 http://orcid.org/0000-0002-4957-5951 http://orcid.org/0000-0002-7954-5059 http://orcid.org/0000-0002-0525-059X |
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eng |
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Sociedade Brasileira de Geologia |
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Sociedade Brasileira de Geologia |
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