Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system

Detalhes bibliográficos
Autor(a) principal: Silva,Júlio César Lopes da
Data de Publicação: 2020
Outros Autores: Azzone,Rogério Guitarrari, Chmyz,Luanna, Guarino,Vincenza, Lima,Nicholas Machado
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=S2317-48892020000300306
Resumo: Abstract Macrocryst assemblages of porphyritic alkaline dikes in the Mantiqueira range (SE Brazil) are mainly composed of clinopyroxene and olivine with different origins. Based on petrographic features, mineral chemistry, and equilibrium relationships with the host liquid, those macrocrysts are classified as xenocrysts, antecrysts, and phenocrysts. Described xenocrysts are mantle olivine, Cr-diopside cores compatible with garnet-bearing mantle facies, green-core clinopyroxene cores compatible with lower crust, and enstatite cores mantled by clinopyroxene, all reported for the first time in this region. Two contrasting types of clinopyroxene antecrysts prevail among the macrocryst cores (both occurring in the same samples and presenting corrosion and sieve textures): primitive colorless diopside and more evolved green-core clinopyroxenes. In the studied rocks, green clinopyroxene zones mantling colorless diopside cores (and vice-versa) are also found. Diopside- and green-cores antecrysts have similar compositions to those from mafic and felsic alkaline melts, respectively. Phenocrysts are mainly related to Ti-augite overgrowths, mantling all other types. Mixing-model curves between mafic and felsic alkaline equilibrium liquids calculated from clinopyroxene antecrysts indicate a hybrid origin for the host matrix. The macrocryst populations of the studied dikes are indicative of a complex plumbing system, recording several processes of an open-system magmatic evolution.
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spelling Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing systemclinopyroxene antecrystsmantle xenocrystsalkaline magmatismcomplex plumbing systemAbstract Macrocryst assemblages of porphyritic alkaline dikes in the Mantiqueira range (SE Brazil) are mainly composed of clinopyroxene and olivine with different origins. Based on petrographic features, mineral chemistry, and equilibrium relationships with the host liquid, those macrocrysts are classified as xenocrysts, antecrysts, and phenocrysts. Described xenocrysts are mantle olivine, Cr-diopside cores compatible with garnet-bearing mantle facies, green-core clinopyroxene cores compatible with lower crust, and enstatite cores mantled by clinopyroxene, all reported for the first time in this region. Two contrasting types of clinopyroxene antecrysts prevail among the macrocryst cores (both occurring in the same samples and presenting corrosion and sieve textures): primitive colorless diopside and more evolved green-core clinopyroxenes. In the studied rocks, green clinopyroxene zones mantling colorless diopside cores (and vice-versa) are also found. Diopside- and green-cores antecrysts have similar compositions to those from mafic and felsic alkaline melts, respectively. Phenocrysts are mainly related to Ti-augite overgrowths, mantling all other types. Mixing-model curves between mafic and felsic alkaline equilibrium liquids calculated from clinopyroxene antecrysts indicate a hybrid origin for the host matrix. The macrocryst populations of the studied dikes are indicative of a complex plumbing system, recording several processes of an open-system magmatic evolution.Sociedade Brasileira de Geologia2020-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892020000300306Brazilian Journal of Geology v.50 n.3 2020reponame:Brazilian Journal of Geologyinstname:Sociedade Brasileira de Geologia (SBGEO)instacron:SBGEO10.1590/2317-4889202020200010info:eu-repo/semantics/openAccessSilva,Júlio César Lopes daAzzone,Rogério GuitarrariChmyz,LuannaGuarino,VincenzaLima,Nicholas Machadoeng2020-08-13T00:00:00Zoai:scielo:S2317-48892020000300306Revistahttp://bjg.siteoficial.ws/index.htmhttps://old.scielo.br/oai/scielo-oai.phpsbgsede@sbgeo.org.br||claudio.riccomini@gmail.com2317-46922317-4692opendoar:2020-08-13T00:00Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO)false
dc.title.none.fl_str_mv Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
title Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
spellingShingle Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
Silva,Júlio César Lopes da
clinopyroxene antecrysts
mantle xenocrysts
alkaline magmatism
complex plumbing system
title_short Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
title_full Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
title_fullStr Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
title_full_unstemmed Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
title_sort Mafic macrocrysts of ultrabasic alkaline dikes from the Mantiqueira Range, SE, Brazil: tracers of a complex plumbing system
author Silva,Júlio César Lopes da
author_facet Silva,Júlio César Lopes da
Azzone,Rogério Guitarrari
Chmyz,Luanna
Guarino,Vincenza
Lima,Nicholas Machado
author_role author
author2 Azzone,Rogério Guitarrari
Chmyz,Luanna
Guarino,Vincenza
Lima,Nicholas Machado
author2_role author
author
author
author
dc.contributor.author.fl_str_mv Silva,Júlio César Lopes da
Azzone,Rogério Guitarrari
Chmyz,Luanna
Guarino,Vincenza
Lima,Nicholas Machado
dc.subject.por.fl_str_mv clinopyroxene antecrysts
mantle xenocrysts
alkaline magmatism
complex plumbing system
topic clinopyroxene antecrysts
mantle xenocrysts
alkaline magmatism
complex plumbing system
description Abstract Macrocryst assemblages of porphyritic alkaline dikes in the Mantiqueira range (SE Brazil) are mainly composed of clinopyroxene and olivine with different origins. Based on petrographic features, mineral chemistry, and equilibrium relationships with the host liquid, those macrocrysts are classified as xenocrysts, antecrysts, and phenocrysts. Described xenocrysts are mantle olivine, Cr-diopside cores compatible with garnet-bearing mantle facies, green-core clinopyroxene cores compatible with lower crust, and enstatite cores mantled by clinopyroxene, all reported for the first time in this region. Two contrasting types of clinopyroxene antecrysts prevail among the macrocryst cores (both occurring in the same samples and presenting corrosion and sieve textures): primitive colorless diopside and more evolved green-core clinopyroxenes. In the studied rocks, green clinopyroxene zones mantling colorless diopside cores (and vice-versa) are also found. Diopside- and green-cores antecrysts have similar compositions to those from mafic and felsic alkaline melts, respectively. Phenocrysts are mainly related to Ti-augite overgrowths, mantling all other types. Mixing-model curves between mafic and felsic alkaline equilibrium liquids calculated from clinopyroxene antecrysts indicate a hybrid origin for the host matrix. The macrocryst populations of the studied dikes are indicative of a complex plumbing system, recording several processes of an open-system magmatic evolution.
publishDate 2020
dc.date.none.fl_str_mv 2020-01-01
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=S2317-48892020000300306
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892020000300306
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/2317-4889202020200010
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.50 n.3 2020
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
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