Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield

[EN] The Namibe region in southwestern Angola represents the southernmost extent of the Southwestern Congo Shield; however, its tectonothermal evolution is still poorly understood. To better constrain the timing and deformation style of the outcropping rocks in this region, we integrated (i) 1:250,0...

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Autores: Escuder Viruete, Javier, Quintana Rodríguez, Luis Antonio, Beranoaguirre de Miguel, Aratz, Montero, Pilar, Gabites, Janet, Valverde Vaquero, Pablo María, Victorino, Américo da Mata Lourenço
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/395277
Acesso em linha:http://hdl.handle.net/10261/395277
Access Level:acceso abierto
Palavra-chave:Southwestern Congo Shield
Eburnean orogeny
Epupa Complex
Namibe Group
Structural analysis
Geochronology
Angola
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spelling Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo ShieldEscuder Viruete, JavierQuintana Rodríguez, Luis AntonioBeranoaguirre de Miguel, AratzMontero, PilarGabites, JanetValverde Vaquero, Pablo MaríaVictorino, Américo da Mata LourençoSouthwestern Congo ShieldEburnean orogenyEpupa ComplexNamibe GroupStructural analysisGeochronologyAngola[EN] The Namibe region in southwestern Angola represents the southernmost extent of the Southwestern Congo Shield; however, its tectonothermal evolution is still poorly understood. To better constrain the timing and deformation style of the outcropping rocks in this region, we integrated (i) 1:250,000-scale lithostratigraphic and structural geological mapping, (ii) SHRIMP U–Pb zircon dating of metamorphic rocks, and (iii) 40Ar/39Ar muscovite cooling ages. The study area comprises the Epupa Complex of ortho- and paragneisses, overlain by the Namibe Group, which is composed of supracrustal metasediments. The sharp lithological contrast, absence of orthogneisses, and the preservation of basal marbles suggest that the protoliths of the Namibe Group were unconformably deposited on the Epupa Complex. Both units experienced polyphase ductile deformation during the Eburnean event. Two penetrative deformation phases (D1 and D2) are overprinted by two later, less pervasive phases (D3 and D4). A subhorizontal D2 shear zone links sinistral transpression in the upper crust with lateral flow in a partially molten lower crust. Peak metamorphic conditions led to widespread anatexis. SHRIMP U–Pb zircon ages from migmatitic leucosomes, granitic–tonalitic orthogneisses, and detrital to metamorphic zircons cluster tightly between 1.82 and 1.80 Ga, while 40Ar/39Ar muscovite ages indicate cooling at ∼1.80 Ga. This implies that the thermal peak, melt segregation, granite emplacement, and cooling occurred within ≤10 Ma. The near-synchronicity of high-grade metamorphism and magmatism, together with the crustal-scale D2 shear architecture, supports a model of hot, thickened crust undergoing vertical strain transfer during late Eburnean sinistral transpression. This study provides the first precise 1.82–1.80 Ga age bracket for the late Eburnean event in southwestern Angola, highlighting a well-preserved subhorizontal attachment zone that couples upper crustal shear with deep crustal flow.Peer reviewedElsevierEscuder Viruete, Javier [0000-0002-3108-9082]Quintana Rodríguez, Luis Antonio [0000-0002-3625-7006]Valverde Vaquero, Pablo María [0000-0002-2184-0848]Victorino, Américo da Mata Lourenço [0000-0001-8665-2197]Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202520252025info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://hdl.handle.net/10261/395277reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1016/j.precamres.2025.107879Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3952772026-05-22T06:33:51Z
dc.title.none.fl_str_mv Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
title Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
spellingShingle Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
Escuder Viruete, Javier
Southwestern Congo Shield
Eburnean orogeny
Epupa Complex
Namibe Group
Structural analysis
Geochronology
Angola
title_short Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
title_full Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
title_fullStr Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
title_full_unstemmed Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
title_sort Lithostratigraphic, structural and geochronological framework of the Namibe region, SW Angola: Insights into the late Eburnean Orogeny in the Congo Shield
dc.creator.none.fl_str_mv Escuder Viruete, Javier
Quintana Rodríguez, Luis Antonio
Beranoaguirre de Miguel, Aratz
Montero, Pilar
Gabites, Janet
Valverde Vaquero, Pablo María
Victorino, Américo da Mata Lourenço
author Escuder Viruete, Javier
author_facet Escuder Viruete, Javier
Quintana Rodríguez, Luis Antonio
Beranoaguirre de Miguel, Aratz
Montero, Pilar
Gabites, Janet
Valverde Vaquero, Pablo María
Victorino, Américo da Mata Lourenço
author_role author
author2 Quintana Rodríguez, Luis Antonio
Beranoaguirre de Miguel, Aratz
Montero, Pilar
Gabites, Janet
Valverde Vaquero, Pablo María
Victorino, Américo da Mata Lourenço
author2_role author
author
author
author
author
author
dc.contributor.none.fl_str_mv Escuder Viruete, Javier [0000-0002-3108-9082]
Quintana Rodríguez, Luis Antonio [0000-0002-3625-7006]
Valverde Vaquero, Pablo María [0000-0002-2184-0848]
Victorino, Américo da Mata Lourenço [0000-0001-8665-2197]
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Southwestern Congo Shield
Eburnean orogeny
Epupa Complex
Namibe Group
Structural analysis
Geochronology
Angola
topic Southwestern Congo Shield
Eburnean orogeny
Epupa Complex
Namibe Group
Structural analysis
Geochronology
Angola
description [EN] The Namibe region in southwestern Angola represents the southernmost extent of the Southwestern Congo Shield; however, its tectonothermal evolution is still poorly understood. To better constrain the timing and deformation style of the outcropping rocks in this region, we integrated (i) 1:250,000-scale lithostratigraphic and structural geological mapping, (ii) SHRIMP U–Pb zircon dating of metamorphic rocks, and (iii) 40Ar/39Ar muscovite cooling ages. The study area comprises the Epupa Complex of ortho- and paragneisses, overlain by the Namibe Group, which is composed of supracrustal metasediments. The sharp lithological contrast, absence of orthogneisses, and the preservation of basal marbles suggest that the protoliths of the Namibe Group were unconformably deposited on the Epupa Complex. Both units experienced polyphase ductile deformation during the Eburnean event. Two penetrative deformation phases (D1 and D2) are overprinted by two later, less pervasive phases (D3 and D4). A subhorizontal D2 shear zone links sinistral transpression in the upper crust with lateral flow in a partially molten lower crust. Peak metamorphic conditions led to widespread anatexis. SHRIMP U–Pb zircon ages from migmatitic leucosomes, granitic–tonalitic orthogneisses, and detrital to metamorphic zircons cluster tightly between 1.82 and 1.80 Ga, while 40Ar/39Ar muscovite ages indicate cooling at ∼1.80 Ga. This implies that the thermal peak, melt segregation, granite emplacement, and cooling occurred within ≤10 Ma. The near-synchronicity of high-grade metamorphism and magmatism, together with the crustal-scale D2 shear architecture, supports a model of hot, thickened crust undergoing vertical strain transfer during late Eburnean sinistral transpression. This study provides the first precise 1.82–1.80 Ga age bracket for the late Eburnean event in southwestern Angola, highlighting a well-preserved subhorizontal attachment zone that couples upper crustal shear with deep crustal flow.
publishDate 2025
dc.date.none.fl_str_mv 2025
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/395277
url http://hdl.handle.net/10261/395277
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1016/j.precamres.2025.107879
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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