Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit
Autor(a) principal: | |
---|---|
Data de Publicação: | 2019 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Geology |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303 |
Resumo: | Abstract 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. |
id |
SBGEO-1_2210dc91e1245f0992eb55c92820f7e7 |
---|---|
oai_identifier_str |
oai:scielo:S2317-48892019000400303 |
network_acronym_str |
SBGEO-1 |
network_name_str |
Brazilian Journal of Geology |
repository_id_str |
|
spelling |
Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim DepositFazenda Bonfim emerald depositSeridó BeltgeologygeochemistryU-Pb and Ar-Ar geochronologyAbstract 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.Sociedade Brasileira de Geologia2019-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303Brazilian Journal of Geology v.49 n.4 2019reponame:Brazilian Journal of Geologyinstname:Sociedade Brasileira de Geologia (SBGEO)instacron:SBGEO10.1590/2317-4889201920190081info:eu-repo/semantics/openAccessSantiago,Judiron SantosSouza,Valmir da SilvaDantas,Elton LuizOliveira,Claudinei Gouveia deeng2020-01-08T00:00:00Zoai:scielo:S2317-48892019000400303Revistahttp://bjg.siteoficial.ws/index.htmhttps://old.scielo.br/oai/scielo-oai.phpsbgsede@sbgeo.org.br||claudio.riccomini@gmail.com2317-46922317-4692opendoar:2020-01-08T00:00Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO)false |
dc.title.none.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 Fazenda Bonfim emerald deposit Seridó Belt geology geochemistry U-Pb and Ar-Ar geochronology |
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.por.fl_str_mv |
Fazenda Bonfim emerald deposit Seridó Belt geology geochemistry U-Pb and Ar-Ar geochronology |
topic |
Fazenda Bonfim emerald deposit Seridó Belt geology geochemistry U-Pb and Ar-Ar geochronology |
description |
Abstract 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.none.fl_str_mv |
2019-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892019000400303 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/2317-4889201920190081 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
dc.source.none.fl_str_mv |
Brazilian Journal of Geology v.49 n.4 2019 reponame:Brazilian Journal of Geology instname:Sociedade Brasileira de Geologia (SBGEO) instacron:SBGEO |
instname_str |
Sociedade Brasileira de Geologia (SBGEO) |
instacron_str |
SBGEO |
institution |
SBGEO |
reponame_str |
Brazilian Journal of Geology |
collection |
Brazilian Journal of Geology |
repository.name.fl_str_mv |
Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO) |
repository.mail.fl_str_mv |
sbgsede@sbgeo.org.br||claudio.riccomini@gmail.com |
_version_ |
1752122399317295104 |