Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais
Autor(a) principal: | |
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Data de Publicação: | 2012 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | por |
Título da fonte: | Anuário do Instituto de Geociências (Online) |
Texto Completo: | https://revistas.ufrj.br/index.php/aigeo/article/view/6936 |
Resumo: | Several gold works dating back from the XVII Century are located over the Congonhas Lineament, a NW-trending steep NE-dipping regional structure composed by oblique slip (left-lateral reverse) én-echelon anastomosing shear zones. Hydrothermal alteration was concentrated on ductile to ductile-ruptile shear zones controlled by rheologic contrasts. Carbonatic alteration is widespread, surrounding chloritization and sericitization zones which envelop cores with silica and sulfide alteration. Grunerite and stilplomelane are present in BIFs close to the outer boundaries of the sulfide zones. The sulfide zone has an outer halo where pyrhotite is the dominant sulfide, followed by an intermediate zone with pyrite, chalcopyrite and pyrhotite. At the nuclei, arsenopyrite is the most common sulfide. If the age of the lower (and mineralised) section of the metavolcanossedimentary belt is Siderian, as its upper part, then gold mineralizations at Congonhas Lineament are Proterozoic instead of Archean. |
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Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas GeraisAlteração Hidrotermal em zona de cisalhamento associada ao lineamento Congonhas, Sul do Quadrilátero Ferrífero, Minas GeraisSeveral gold works dating back from the XVII Century are located over the Congonhas Lineament, a NW-trending steep NE-dipping regional structure composed by oblique slip (left-lateral reverse) én-echelon anastomosing shear zones. Hydrothermal alteration was concentrated on ductile to ductile-ruptile shear zones controlled by rheologic contrasts. Carbonatic alteration is widespread, surrounding chloritization and sericitization zones which envelop cores with silica and sulfide alteration. Grunerite and stilplomelane are present in BIFs close to the outer boundaries of the sulfide zones. The sulfide zone has an outer halo where pyrhotite is the dominant sulfide, followed by an intermediate zone with pyrite, chalcopyrite and pyrhotite. At the nuclei, arsenopyrite is the most common sulfide. If the age of the lower (and mineralised) section of the metavolcanossedimentary belt is Siderian, as its upper part, then gold mineralizations at Congonhas Lineament are Proterozoic instead of Archean.O Lineamento Congonhas hospeda lavras inativas de ouro que datam Século XVIII, sendo composto por zonas de cisalhamento SE-NW escalonadas e anastomosadas com mergulhos fortes a subverticais para NE, de movimentação oblíqua (sinistral reversa). A alteração hidrotermal se concentrou em zonas de cisalhamento dúcteis a dúctil-rúpteis controladas por contrastes litológicos (BIFs e metapelitos intercalados a metabasaltos). A alteração carbonática é a mais volumosa, ocorrendo do núcleo até as bordas da região hidrotermalisada. Zonas de cloritização e sericitização se seguem, circundando um núcleo de silicificação e sulfetação. Grunerita e stilpnomelana ocorrem nos BIFs, tanto nas proximidades das zonas de sulfe-tação quanto em suas partes mais externas. As zonas de sulfetação são formadas por halos externos onde a pirrotita é o sulfeto dominante, seguindo-se zonas intermediárias com pirita, calcopirita e pirrotita. No núcleo das zonas sulfetadas predomina a arsenopirita. É possível que a mineralização aurífera do Lineamento Congonhas seja Proterozoica e não Arqueana, caso a porção estratigráfica inferior e mineralizada do cinturão metavulcanossedimentar seja de idade Sideriana, como a superior.Universidade Federal do Rio de Janeiro2012-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://revistas.ufrj.br/index.php/aigeo/article/view/693610.11137/2012_2_55_64Anuário do Instituto de Geociências; Vol 35, No 2 (2012); 55-64Anuário do Instituto de Geociências; Vol 35, No 2 (2012); 55-641982-39080101-9759reponame:Anuário do Instituto de Geociências (Online)instname:Universidade Federal do Rio de Janeiro (UFRJ)instacron:UFRJporhttps://revistas.ufrj.br/index.php/aigeo/article/view/6936/5503Copyright (c) 2012 Anuário do Instituto de Geociênciashttp://creativecommons.org/licenses/by/4.0info:eu-repo/semantics/openAccessCorrêa Neto, Atlas VasconcelosAlmeida, Antônio Modesto deCaputo Neto, VitorGuerrero, Júlia Campos2017-01-23T22:34:48Zoai:www.revistas.ufrj.br:article/6936Revistahttps://revistas.ufrj.br/index.php/aigeo/indexPUBhttps://revistas.ufrj.br/index.php/aigeo/oaianuario@igeo.ufrj.br||1982-39080101-9759opendoar:2017-01-23T22:34:48Anuário do Instituto de Geociências (Online) - Universidade Federal do Rio de Janeiro (UFRJ)false |
dc.title.none.fl_str_mv |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais Alteração Hidrotermal em zona de cisalhamento associada ao lineamento Congonhas, Sul do Quadrilátero Ferrífero, Minas Gerais |
title |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
spellingShingle |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais Corrêa Neto, Atlas Vasconcelos |
title_short |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
title_full |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
title_fullStr |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
title_full_unstemmed |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
title_sort |
Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais |
author |
Corrêa Neto, Atlas Vasconcelos |
author_facet |
Corrêa Neto, Atlas Vasconcelos Almeida, Antônio Modesto de Caputo Neto, Vitor Guerrero, Júlia Campos |
author_role |
author |
author2 |
Almeida, Antônio Modesto de Caputo Neto, Vitor Guerrero, Júlia Campos |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Corrêa Neto, Atlas Vasconcelos Almeida, Antônio Modesto de Caputo Neto, Vitor Guerrero, Júlia Campos |
description |
Several gold works dating back from the XVII Century are located over the Congonhas Lineament, a NW-trending steep NE-dipping regional structure composed by oblique slip (left-lateral reverse) én-echelon anastomosing shear zones. Hydrothermal alteration was concentrated on ductile to ductile-ruptile shear zones controlled by rheologic contrasts. Carbonatic alteration is widespread, surrounding chloritization and sericitization zones which envelop cores with silica and sulfide alteration. Grunerite and stilplomelane are present in BIFs close to the outer boundaries of the sulfide zones. The sulfide zone has an outer halo where pyrhotite is the dominant sulfide, followed by an intermediate zone with pyrite, chalcopyrite and pyrhotite. At the nuclei, arsenopyrite is the most common sulfide. If the age of the lower (and mineralised) section of the metavolcanossedimentary belt is Siderian, as its upper part, then gold mineralizations at Congonhas Lineament are Proterozoic instead of Archean. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012-12-01 |
dc.type.none.fl_str_mv |
|
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://revistas.ufrj.br/index.php/aigeo/article/view/6936 10.11137/2012_2_55_64 |
url |
https://revistas.ufrj.br/index.php/aigeo/article/view/6936 |
identifier_str_mv |
10.11137/2012_2_55_64 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.relation.none.fl_str_mv |
https://revistas.ufrj.br/index.php/aigeo/article/view/6936/5503 |
dc.rights.driver.fl_str_mv |
Copyright (c) 2012 Anuário do Instituto de Geociências http://creativecommons.org/licenses/by/4.0 info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Copyright (c) 2012 Anuário do Instituto de Geociências http://creativecommons.org/licenses/by/4.0 |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal do Rio de Janeiro |
publisher.none.fl_str_mv |
Universidade Federal do Rio de Janeiro |
dc.source.none.fl_str_mv |
Anuário do Instituto de Geociências; Vol 35, No 2 (2012); 55-64 Anuário do Instituto de Geociências; Vol 35, No 2 (2012); 55-64 1982-3908 0101-9759 reponame:Anuário do Instituto de Geociências (Online) instname:Universidade Federal do Rio de Janeiro (UFRJ) instacron:UFRJ |
instname_str |
Universidade Federal do Rio de Janeiro (UFRJ) |
instacron_str |
UFRJ |
institution |
UFRJ |
reponame_str |
Anuário do Instituto de Geociências (Online) |
collection |
Anuário do Instituto de Geociências (Online) |
repository.name.fl_str_mv |
Anuário do Instituto de Geociências (Online) - Universidade Federal do Rio de Janeiro (UFRJ) |
repository.mail.fl_str_mv |
anuario@igeo.ufrj.br|| |
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1797053545079373824 |