Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids

Garnet is an uncommon accessory mineral in igneous rocks but is petrologically significant. The Peñón Rosado granite (469± 4Ma) at Cerro Asperecito is an S-type granite that contains an unusual amount of magmatic garnet. Combined petrology, chemistry/ mineralogy and whole-rock geochemistry indicates...

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Detalles Bibliográficos
Autores: Dahlquist, Juan A., Galindo Francisco, María Del Carmen, Pankhurst, R.J., Rapela, Carlos W., Alasino, Pablo H., Saavedra, Julio, Fanning, C.M.
Tipo de recurso: artículo
Fecha de publicación:1995
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/56987
Acceso en línea:https://hdl.handle.net/20.500.14352/56987
Access Level:acceso abierto
Palabra clave:552.3
S-type granite
Partial melting
Fractional crystallization
Garnet zoning
Petrología
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spelling Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoidsDahlquist, Juan A.Galindo Francisco, María Del CarmenPankhurst, R.J.Rapela, Carlos W.Alasino, Pablo H.Saavedra, JulioFanning, C.M.552.3S-type granitePartial meltingFractional crystallizationGarnet zoningPetrologíaGarnet is an uncommon accessory mineral in igneous rocks but is petrologically significant. The Peñón Rosado granite (469± 4Ma) at Cerro Asperecito is an S-type granite that contains an unusual amount of magmatic garnet. Combined petrology, chemistry/ mineralogy and whole-rock geochemistry indicates that the magma was produced by partial melting of the surrounding metasedimentary rocks and subsequent differentiation by fractional crystallization during emplacement, with garnet occurring throughout the crystallization sequence. Three facies are recognised: PRG1 (SiO2=65.70%) represents cumulates, PRG2 (SiO2=70.88%) represents a differentiated melt, and PRG3 (SiO2=74.59%) a residual melt. The fractionation of Mn in garnet and the proportion of garnet crystallizing are roughly controlled by the evolving composition of the different granitic facies.Geothermobaric calculations reveal an initial crystallization temperature of 764°–792 °Cand a pressure of 5.9–6.0 kb, indicating that the parental magma was emplaced atmiddle crustal depths (∼1920 km) in moderate–low magmatic temperature conditions.Major (CaO, Na2O,K2O) and trace element (Rb, Sr, Ba) contents in the Peñón Rosado granite strongly suggest anatexis was the outcome of H2O-fluxed melting of metagreywacke, with heat input from a major metaluminous suite. Our studies reveal that garnet formed by direct crystallization from peraluminous magma in equilibrium with solid phases such as biotite and white mica.We confirm previous suggestions that zoning in garnet is strongly temperature-dependent. Thus, magmatic garnets in granitic rocks crystallized above ∼ 700 °C have “spessartine inverse bell-shaped profile” or are unzoned, whereas garnet exhibiting “spessartine bell-shaped profile” must be considered of metamorphic origin (i.e., xenocrystic) or formed in very felsic magmas (SiO2=73–76%) crystallizing below ∼ 700 °C. © 2006 Elsevier B.V. All rights reserved.Elsevier Science B.V., AmsterdamUniversidad Complutense de Madrid19951995-01-0119951995-01-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/56987reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/569872026-06-02T12:44:21Z
dc.title.none.fl_str_mv Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
title Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
spellingShingle Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
Dahlquist, Juan A.
552.3
S-type granite
Partial melting
Fractional crystallization
Garnet zoning
Petrología
title_short Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
title_full Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
title_fullStr Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
title_full_unstemmed Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
title_sort Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids
dc.creator.none.fl_str_mv Dahlquist, Juan A.
Galindo Francisco, María Del Carmen
Pankhurst, R.J.
Rapela, Carlos W.
Alasino, Pablo H.
Saavedra, Julio
Fanning, C.M.
author Dahlquist, Juan A.
author_facet Dahlquist, Juan A.
Galindo Francisco, María Del Carmen
Pankhurst, R.J.
Rapela, Carlos W.
Alasino, Pablo H.
Saavedra, Julio
Fanning, C.M.
author_role author
author2 Galindo Francisco, María Del Carmen
Pankhurst, R.J.
Rapela, Carlos W.
Alasino, Pablo H.
Saavedra, Julio
Fanning, C.M.
author2_role author
author
author
author
author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 552.3
S-type granite
Partial melting
Fractional crystallization
Garnet zoning
Petrología
topic 552.3
S-type granite
Partial melting
Fractional crystallization
Garnet zoning
Petrología
description Garnet is an uncommon accessory mineral in igneous rocks but is petrologically significant. The Peñón Rosado granite (469± 4Ma) at Cerro Asperecito is an S-type granite that contains an unusual amount of magmatic garnet. Combined petrology, chemistry/ mineralogy and whole-rock geochemistry indicates that the magma was produced by partial melting of the surrounding metasedimentary rocks and subsequent differentiation by fractional crystallization during emplacement, with garnet occurring throughout the crystallization sequence. Three facies are recognised: PRG1 (SiO2=65.70%) represents cumulates, PRG2 (SiO2=70.88%) represents a differentiated melt, and PRG3 (SiO2=74.59%) a residual melt. The fractionation of Mn in garnet and the proportion of garnet crystallizing are roughly controlled by the evolving composition of the different granitic facies.Geothermobaric calculations reveal an initial crystallization temperature of 764°–792 °Cand a pressure of 5.9–6.0 kb, indicating that the parental magma was emplaced atmiddle crustal depths (∼1920 km) in moderate–low magmatic temperature conditions.Major (CaO, Na2O,K2O) and trace element (Rb, Sr, Ba) contents in the Peñón Rosado granite strongly suggest anatexis was the outcome of H2O-fluxed melting of metagreywacke, with heat input from a major metaluminous suite. Our studies reveal that garnet formed by direct crystallization from peraluminous magma in equilibrium with solid phases such as biotite and white mica.We confirm previous suggestions that zoning in garnet is strongly temperature-dependent. Thus, magmatic garnets in granitic rocks crystallized above ∼ 700 °C have “spessartine inverse bell-shaped profile” or are unzoned, whereas garnet exhibiting “spessartine bell-shaped profile” must be considered of metamorphic origin (i.e., xenocrystic) or formed in very felsic magmas (SiO2=73–76%) crystallizing below ∼ 700 °C. © 2006 Elsevier B.V. All rights reserved.
publishDate 1995
dc.date.none.fl_str_mv 1995
1995-01-01
1995
1995-01-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/56987
url https://hdl.handle.net/20.500.14352/56987
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier Science B.V., Amsterdam
publisher.none.fl_str_mv Elsevier Science B.V., Amsterdam
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
_version_ 1869410502021480448
score 15.300719

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