Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain

Two broad series of peraluminous granite types can be distinguished in the Central System of Spain. The first group consists of cordierite-bearing granites that are moderately peraluminous in composition (peraluminous S-type granites, PS). The second is composed of amphibole/allanite-bearing granite...

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Autores: Villaseca González, Carlos, Barbero González, Luis C.
Tipo de recurso: artículo
Fecha de publicación:1994
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/57028
Acceso en línea:https://hdl.handle.net/20.500.14352/57028
Access Level:acceso abierto
Palabra clave:552.3(234.1)
Hercynian peraluminous granitoids
Mineral-whole rock correlation
Al-Ti-Fe-Mg minerals
Cordierite
Garnet
Central Spain
Petrología
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spelling Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central SpainVillaseca González, CarlosBarbero González, Luis C.552.3(234.1)Hercynian peraluminous granitoidsMineral-whole rock correlationAl-Ti-Fe-Mg mineralsCordieriteGarnetCentral SpainPetrologíaTwo broad series of peraluminous granite types can be distinguished in the Central System of Spain. The first group consists of cordierite-bearing granites that are moderately peraluminous in composition (peraluminous S-type granites, PS). The second is composed of amphibole/allanite-bearing granites, weakly peraluminous in composition (peraluminous I-type, PI). These granite types evolved through complex igneous fractionation processes. Both peraluminous granite types show differences in the chemical composition of biotite and cordierite; cordierite is common in PS granites but restricted to some highly fractionated PI granites. Garnet and ilmenite cannot be used as chemical criteria for distinguishing the two series. The Al and Na content of biotite and cordierite correlate well with the granite type (PS and PI). The higher Na content in biotite (and cordierite) of PS granites is noteworthy. When plotted in a Na vs. [VI1A1 diagram biotites are located in different fields according to the peraluminosity degree of the granite type. The estimated Fe3+/(Fe3++Fe2+) ratio of biotite is higher in PI than in PS granites, although this value is very pluton-dependent. Several compositional variations of Al-Ti-Fe-Mg (ATFM) minerals are functions of the degree of fractionation or evolution of the magma, irrespectively of its peraluminosity. Other chemical features of ATFM phases, such as XFe or XMΠ, can be used as fractionation indices. Thus, the more acid the magma, the higher XFe and XMΠ in ATFM minerals. This correlation is not linear showing a rapid increase for silica values of SiO2 ≥ 74 %. Usually, XFe garnet > XFe biotite > XFe cordierite, and XMΠ ilmenite = XMΠ garnet > XMΠ cordierite > XMΠ biotite, while XFe and XMΠ of whole rock are very close to biotite values. The high increase in Mn content, more marked than in Fe, in all AFM phases in the silica-rich granites (SiO2 = 74 %), can be interpreted as a consequence of the incompatible behaviour of this element in highly evolved granites, that are sufficiently poor in Ti, Mg and Fe to prevent or diminish crystallization of ore-minerals, such as ilmenite.E. Schweizerbart'sche VerlagsbuchhandlungUniversidad Complutense de Madrid19941994-01-0119941994-01-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/57028reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/570282026-06-02T12:44:21Z
dc.title.none.fl_str_mv Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
title Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
spellingShingle Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
Villaseca González, Carlos
552.3(234.1)
Hercynian peraluminous granitoids
Mineral-whole rock correlation
Al-Ti-Fe-Mg minerals
Cordierite
Garnet
Central Spain
Petrología
title_short Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
title_full Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
title_fullStr Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
title_full_unstemmed Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
title_sort Chemical variability of Al-Ti-Fe-Mg minerals in peraluminous granitoid rocks from Central Spain
dc.creator.none.fl_str_mv Villaseca González, Carlos
Barbero González, Luis C.
author Villaseca González, Carlos
author_facet Villaseca González, Carlos
Barbero González, Luis C.
author_role author
author2 Barbero González, Luis C.
author2_role author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 552.3(234.1)
Hercynian peraluminous granitoids
Mineral-whole rock correlation
Al-Ti-Fe-Mg minerals
Cordierite
Garnet
Central Spain
Petrología
topic 552.3(234.1)
Hercynian peraluminous granitoids
Mineral-whole rock correlation
Al-Ti-Fe-Mg minerals
Cordierite
Garnet
Central Spain
Petrología
description Two broad series of peraluminous granite types can be distinguished in the Central System of Spain. The first group consists of cordierite-bearing granites that are moderately peraluminous in composition (peraluminous S-type granites, PS). The second is composed of amphibole/allanite-bearing granites, weakly peraluminous in composition (peraluminous I-type, PI). These granite types evolved through complex igneous fractionation processes. Both peraluminous granite types show differences in the chemical composition of biotite and cordierite; cordierite is common in PS granites but restricted to some highly fractionated PI granites. Garnet and ilmenite cannot be used as chemical criteria for distinguishing the two series. The Al and Na content of biotite and cordierite correlate well with the granite type (PS and PI). The higher Na content in biotite (and cordierite) of PS granites is noteworthy. When plotted in a Na vs. [VI1A1 diagram biotites are located in different fields according to the peraluminosity degree of the granite type. The estimated Fe3+/(Fe3++Fe2+) ratio of biotite is higher in PI than in PS granites, although this value is very pluton-dependent. Several compositional variations of Al-Ti-Fe-Mg (ATFM) minerals are functions of the degree of fractionation or evolution of the magma, irrespectively of its peraluminosity. Other chemical features of ATFM phases, such as XFe or XMΠ, can be used as fractionation indices. Thus, the more acid the magma, the higher XFe and XMΠ in ATFM minerals. This correlation is not linear showing a rapid increase for silica values of SiO2 ≥ 74 %. Usually, XFe garnet > XFe biotite > XFe cordierite, and XMΠ ilmenite = XMΠ garnet > XMΠ cordierite > XMΠ biotite, while XFe and XMΠ of whole rock are very close to biotite values. The high increase in Mn content, more marked than in Fe, in all AFM phases in the silica-rich granites (SiO2 = 74 %), can be interpreted as a consequence of the incompatible behaviour of this element in highly evolved granites, that are sufficiently poor in Ti, Mg and Fe to prevent or diminish crystallization of ore-minerals, such as ilmenite.
publishDate 1994
dc.date.none.fl_str_mv 1994
1994-01-01
1994
1994-01-01
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/20.500.14352/57028
url https://hdl.handle.net/20.500.14352/57028
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 E. Schweizerbart'sche Verlagsbuchhandlung
publisher.none.fl_str_mv E. Schweizerbart'sche Verlagsbuchhandlung
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
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