Hydrothermal alteration in a shear zone associated to the Congonhas lineament, Southern Quadrilátero Ferrífero, Minas Gerais

Detalhes bibliográficos
Autor(a) principal: Corrêa Neto, Atlas Vasconcelos
Data de Publicação: 2012
Outros Autores: Almeida, Antônio Modesto de, Caputo Neto, Vitor, Guerrero, Júlia Campos
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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spelling 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
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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
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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
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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)
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