Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)

Bibliographic Details
Main Author: Oliveira, António
Publication Date: 2025
Other Authors: Martins, Helena, Sant'Ovaia, H.
Format: Article
Language: eng
Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
Download full: http://hdl.handle.net/10400.9/5663
Summary: ABSTRACT: This study is dedicated to the presentation and interpretation of whole-rock geochemical data concerning a few mafic subvolcanic dykes located in northern Portugal, related to the late to posttectonic stages of the Variscan orogeny. Overall, the analyzed rocks are reasonably fresh, ultrabasic to intermediate, metaluminous to moderately peraluminous, and calc-alkaline or alkaline. There is no evidence implying the occurrence of crustal contamination, but crystal fractionation is likely to have played either a minor or more meaningful role on the petrogenetic evolution. While most dykes were probably generated from subduction-modified, metasomatically-enriched lithospheric sources, others possibly derived from the asthenosphere. There are also important differences regarding the residual mineralogy of the sources, as well as the melting degrees.
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spelling Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)Heterogeneidade composicional dos ciques máficos subvulcânicos, tardi a pós-variscos do norte de Portugal (Zona Centro Ibérica)LamprophyresDoleritesDykesVariscan orogenyLamprófirosDoleritosDiquesMagmatismoOrogenia VariscaABSTRACT: This study is dedicated to the presentation and interpretation of whole-rock geochemical data concerning a few mafic subvolcanic dykes located in northern Portugal, related to the late to posttectonic stages of the Variscan orogeny. Overall, the analyzed rocks are reasonably fresh, ultrabasic to intermediate, metaluminous to moderately peraluminous, and calc-alkaline or alkaline. There is no evidence implying the occurrence of crustal contamination, but crystal fractionation is likely to have played either a minor or more meaningful role on the petrogenetic evolution. While most dykes were probably generated from subduction-modified, metasomatically-enriched lithospheric sources, others possibly derived from the asthenosphere. There are also important differences regarding the residual mineralogy of the sources, as well as the melting degrees.RESUMO: O presente trabalho dedica-se à apresentação e interpretação de dados de geoquímica de rocha total sobre alguns diques subvulcânicos máficos, localizados no norte de Portugal, associados às fases tardi a pós-tectónicas da orogenia Varisca. Em geral, as rochas analisadas são razoavelmente frescas, ultrabásicas a intermédias, metaluminosas a moderadamente peraluminosas, e calcoalcalinas ou alcalinas. Não existem evidências a favor da ocorrência de contaminação crustal, mas a cristalização fracionada deverá ter desempenhado um papel mais ou menos significativo sobre a evolução petrogenética. Embora a maioria dos diques tenha provavelmente sido gerada a partir de fontes litosféricas, modificadas por subducção e enriquecidas metassomaticamente, os restantes possivelmente derivaram da astenosfera. Existem ainda diferenças importantes no que diz respeito à mineralogia residual das fontes, assim como sobre os respetivos graus de fusão.LNEG - Laboratório Nacional de Energia e GeologiaRepositório do LNEGOliveira, AntónioMartins, HelenaSant'Ovaia, H.2025-05-09T15:24:36Z2025-042025-04-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.9/5663eng0873-948X10.34637/7dm2-f386info:eu-repo/semantics/openAccessreponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiainstacron:RCAAP2025-05-18T04:48:37Zoai:repositorio.lneg.pt:10400.9/5663Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireinfo@rcaap.ptopendoar:https://opendoar.ac.uk/repository/71602025-05-29T07:13:41.650984Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiafalse
dc.title.none.fl_str_mv Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
Heterogeneidade composicional dos ciques máficos subvulcânicos, tardi a pós-variscos do norte de Portugal (Zona Centro Ibérica)
title Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
spellingShingle Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
Oliveira, António
Lamprophyres
Dolerites
Dykes
Variscan orogeny
Lamprófiros
Doleritos
Diques
Magmatismo
Orogenia Varisca
title_short Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
title_full Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
title_fullStr Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
title_full_unstemmed Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
title_sort Compositional heterogeneity of late to post-Variscan, mafic subvolcanic dykes from northern Portugal (Central Iberian Zone)
author Oliveira, António
author_facet Oliveira, António
Martins, Helena
Sant'Ovaia, H.
author_role author
author2 Martins, Helena
Sant'Ovaia, H.
author2_role author
author
dc.contributor.none.fl_str_mv Repositório do LNEG
dc.contributor.author.fl_str_mv Oliveira, António
Martins, Helena
Sant'Ovaia, H.
dc.subject.por.fl_str_mv Lamprophyres
Dolerites
Dykes
Variscan orogeny
Lamprófiros
Doleritos
Diques
Magmatismo
Orogenia Varisca
topic Lamprophyres
Dolerites
Dykes
Variscan orogeny
Lamprófiros
Doleritos
Diques
Magmatismo
Orogenia Varisca
description ABSTRACT: This study is dedicated to the presentation and interpretation of whole-rock geochemical data concerning a few mafic subvolcanic dykes located in northern Portugal, related to the late to posttectonic stages of the Variscan orogeny. Overall, the analyzed rocks are reasonably fresh, ultrabasic to intermediate, metaluminous to moderately peraluminous, and calc-alkaline or alkaline. There is no evidence implying the occurrence of crustal contamination, but crystal fractionation is likely to have played either a minor or more meaningful role on the petrogenetic evolution. While most dykes were probably generated from subduction-modified, metasomatically-enriched lithospheric sources, others possibly derived from the asthenosphere. There are also important differences regarding the residual mineralogy of the sources, as well as the melting degrees.
publishDate 2025
dc.date.none.fl_str_mv 2025-05-09T15:24:36Z
2025-04
2025-04-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10400.9/5663
url http://hdl.handle.net/10400.9/5663
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 0873-948X
10.34637/7dm2-f386
dc.rights.driver.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 LNEG - Laboratório Nacional de Energia e Geologia
publisher.none.fl_str_mv LNEG - Laboratório Nacional de Energia e Geologia
dc.source.none.fl_str_mv reponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron:RCAAP
instname_str FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron_str RCAAP
institution RCAAP
reponame_str Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
collection Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
repository.name.fl_str_mv Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
repository.mail.fl_str_mv info@rcaap.pt
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