Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling

Autores
Geuna, Silvana Evangelina; Mcenroe, S. A.; Robinson, P.; Escosteguy, Leonardo Darío
Año de publicación
2008
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Devonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late- to post-orogenic monzogranites emplaced in a metamorphic-plutonic basement. Two groups of Devonian granitoids are distinguished: (1) metaaluminous to weakly peraluminous, hornblende-biotite bearing granitoids, and (2) peraluminous, biotite-(muscovite) bearing granitoids. Groups 1 and 2 are characterized by accessory phases of sphene-magnetite with high susceptibility, and ilmenite-(monazite-uraninite) with low susceptibility, respectively. The magnetic assemblage of the Group 2 Achala Batholith, predominantly paramagnetic, is the subject of this paper Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 1.5 × 10 -4 SI. Twenty-one sites showed titanohaematite as the magnetic carrier of a stable remanence. The titanohaematite is an accessory mineral and contains exsolved disc-shaped intergrowths of ilmenite. The weak magnetism of Achala monzogranite facies contrasts with the magnetic character of other Devonian porphyritic, batholithic monzogranites in the region. The virtual absence of magnetite, together with the presence of exsolved titanohaematite and Mn-ilmenite indicate crystallization and cooling under more oxidizing conditions. Oxidizing conditions continued into the subsolidus, causing late-stage reactions of ilmenite host grains to ilmenite + rutile+ haematite, and titanohaematite to ilmenite-poorer haematite + rutile. These reactions resulted in low susceptibility values and a strong reduction of natural remanent magnetization (NRM) intensities. Thermal demagnetization, up to 620-640°C, isolated steeply dipping, dual-polarity remanence directions. The coincidence of the Achala paleomagnetic pole with the 380-360 Myr segment of the Gondwana Apparent Polar Wander Path and the U-Pb zircon age implies that the remanence was acquired soon after emplacement.
Fil: Geuna, Silvana Evangelina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Mcenroe, S. A.. Geological Survey of Norway; Noruega
Fil: Robinson, P.. Geological Survey of Norway; Noruega
Fil: Escosteguy, Leonardo Darío. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Materia
Magnetic Mineralogy And Petrology
Physics And Chemistry of Magma Bodies
Rockand Mineral Magnetism
South America
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/73932
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/73932
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and coolingGeuna, Silvana EvangelinaMcenroe, S. A.Robinson, P.Escosteguy, Leonardo DaríoMagnetic Mineralogy And PetrologyPhysics And Chemistry of Magma BodiesRockand Mineral MagnetismSouth Americahttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Devonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late- to post-orogenic monzogranites emplaced in a metamorphic-plutonic basement. Two groups of Devonian granitoids are distinguished: (1) metaaluminous to weakly peraluminous, hornblende-biotite bearing granitoids, and (2) peraluminous, biotite-(muscovite) bearing granitoids. Groups 1 and 2 are characterized by accessory phases of sphene-magnetite with high susceptibility, and ilmenite-(monazite-uraninite) with low susceptibility, respectively. The magnetic assemblage of the Group 2 Achala Batholith, predominantly paramagnetic, is the subject of this paper Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 1.5 × 10 -4 SI. Twenty-one sites showed titanohaematite as the magnetic carrier of a stable remanence. The titanohaematite is an accessory mineral and contains exsolved disc-shaped intergrowths of ilmenite. The weak magnetism of Achala monzogranite facies contrasts with the magnetic character of other Devonian porphyritic, batholithic monzogranites in the region. The virtual absence of magnetite, together with the presence of exsolved titanohaematite and Mn-ilmenite indicate crystallization and cooling under more oxidizing conditions. Oxidizing conditions continued into the subsolidus, causing late-stage reactions of ilmenite host grains to ilmenite + rutile+ haematite, and titanohaematite to ilmenite-poorer haematite + rutile. These reactions resulted in low susceptibility values and a strong reduction of natural remanent magnetization (NRM) intensities. Thermal demagnetization, up to 620-640°C, isolated steeply dipping, dual-polarity remanence directions. The coincidence of the Achala paleomagnetic pole with the 380-360 Myr segment of the Gondwana Apparent Polar Wander Path and the U-Pb zircon age implies that the remanence was acquired soon after emplacement.Fil: Geuna, Silvana Evangelina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mcenroe, S. A.. Geological Survey of Norway; NoruegaFil: Robinson, P.. Geological Survey of Norway; NoruegaFil: Escosteguy, Leonardo Darío. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaWiley Blackwell Publishing, Inc2008-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/73932Geuna, Silvana Evangelina; Mcenroe, S. A.; Robinson, P.; Escosteguy, Leonardo Darío; Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling; Wiley Blackwell Publishing, Inc; Geophysical Journal International; 175; 3; 12-2008; 925-9410956-540XCONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-246X.2008.03964.xinfo:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/gji/article/175/3/925/637817info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:20:09Zoai:ri.conicet.gov.ar:11336/73932instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:20:10.194CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
title Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
spellingShingle Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
Geuna, Silvana Evangelina
Magnetic Mineralogy And Petrology
Physics And Chemistry of Magma Bodies
Rockand Mineral Magnetism
South America
title_short Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
title_full Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
title_fullStr Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
title_full_unstemmed Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
title_sort Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
dc.creator.none.fl_str_mv Geuna, Silvana Evangelina
Mcenroe, S. A.
Robinson, P.
Escosteguy, Leonardo Darío
author Geuna, Silvana Evangelina
author_facet Geuna, Silvana Evangelina
Mcenroe, S. A.
Robinson, P.
Escosteguy, Leonardo Darío
author_role author
author2 Mcenroe, S. A.
Robinson, P.
Escosteguy, Leonardo Darío
author2_role author
author
author
dc.subject.none.fl_str_mv Magnetic Mineralogy And Petrology
Physics And Chemistry of Magma Bodies
Rockand Mineral Magnetism
South America
topic Magnetic Mineralogy And Petrology
Physics And Chemistry of Magma Bodies
Rockand Mineral Magnetism
South America
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Devonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late- to post-orogenic monzogranites emplaced in a metamorphic-plutonic basement. Two groups of Devonian granitoids are distinguished: (1) metaaluminous to weakly peraluminous, hornblende-biotite bearing granitoids, and (2) peraluminous, biotite-(muscovite) bearing granitoids. Groups 1 and 2 are characterized by accessory phases of sphene-magnetite with high susceptibility, and ilmenite-(monazite-uraninite) with low susceptibility, respectively. The magnetic assemblage of the Group 2 Achala Batholith, predominantly paramagnetic, is the subject of this paper Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 1.5 × 10 -4 SI. Twenty-one sites showed titanohaematite as the magnetic carrier of a stable remanence. The titanohaematite is an accessory mineral and contains exsolved disc-shaped intergrowths of ilmenite. The weak magnetism of Achala monzogranite facies contrasts with the magnetic character of other Devonian porphyritic, batholithic monzogranites in the region. The virtual absence of magnetite, together with the presence of exsolved titanohaematite and Mn-ilmenite indicate crystallization and cooling under more oxidizing conditions. Oxidizing conditions continued into the subsolidus, causing late-stage reactions of ilmenite host grains to ilmenite + rutile+ haematite, and titanohaematite to ilmenite-poorer haematite + rutile. These reactions resulted in low susceptibility values and a strong reduction of natural remanent magnetization (NRM) intensities. Thermal demagnetization, up to 620-640°C, isolated steeply dipping, dual-polarity remanence directions. The coincidence of the Achala paleomagnetic pole with the 380-360 Myr segment of the Gondwana Apparent Polar Wander Path and the U-Pb zircon age implies that the remanence was acquired soon after emplacement.
Fil: Geuna, Silvana Evangelina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Instituto de Geofísica "Daniel Valencio"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Mcenroe, S. A.. Geological Survey of Norway; Noruega
Fil: Robinson, P.. Geological Survey of Norway; Noruega
Fil: Escosteguy, Leonardo Darío. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
description Devonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late- to post-orogenic monzogranites emplaced in a metamorphic-plutonic basement. Two groups of Devonian granitoids are distinguished: (1) metaaluminous to weakly peraluminous, hornblende-biotite bearing granitoids, and (2) peraluminous, biotite-(muscovite) bearing granitoids. Groups 1 and 2 are characterized by accessory phases of sphene-magnetite with high susceptibility, and ilmenite-(monazite-uraninite) with low susceptibility, respectively. The magnetic assemblage of the Group 2 Achala Batholith, predominantly paramagnetic, is the subject of this paper Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 1.5 × 10 -4 SI. Twenty-one sites showed titanohaematite as the magnetic carrier of a stable remanence. The titanohaematite is an accessory mineral and contains exsolved disc-shaped intergrowths of ilmenite. The weak magnetism of Achala monzogranite facies contrasts with the magnetic character of other Devonian porphyritic, batholithic monzogranites in the region. The virtual absence of magnetite, together with the presence of exsolved titanohaematite and Mn-ilmenite indicate crystallization and cooling under more oxidizing conditions. Oxidizing conditions continued into the subsolidus, causing late-stage reactions of ilmenite host grains to ilmenite + rutile+ haematite, and titanohaematite to ilmenite-poorer haematite + rutile. These reactions resulted in low susceptibility values and a strong reduction of natural remanent magnetization (NRM) intensities. Thermal demagnetization, up to 620-640°C, isolated steeply dipping, dual-polarity remanence directions. The coincidence of the Achala paleomagnetic pole with the 380-360 Myr segment of the Gondwana Apparent Polar Wander Path and the U-Pb zircon age implies that the remanence was acquired soon after emplacement.
publishDate 2008
dc.date.none.fl_str_mv 2008-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/73932
Geuna, Silvana Evangelina; Mcenroe, S. A.; Robinson, P.; Escosteguy, Leonardo Darío; Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling; Wiley Blackwell Publishing, Inc; Geophysical Journal International; 175; 3; 12-2008; 925-941
0956-540X
CONICET Digital
CONICET
url http://hdl.handle.net/11336/73932
identifier_str_mv Geuna, Silvana Evangelina; Mcenroe, S. A.; Robinson, P.; Escosteguy, Leonardo Darío; Magnetic petrology of the Devonian Achala Batholith, Argentina: Titanohaematite as an indicator of highly oxidized magma during crystallization and cooling; Wiley Blackwell Publishing, Inc; Geophysical Journal International; 175; 3; 12-2008; 925-941
0956-540X
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-246X.2008.03964.x
info:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/gji/article/175/3/925/637817
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
application/pdf
dc.publisher.none.fl_str_mv Wiley Blackwell Publishing, Inc
publisher.none.fl_str_mv Wiley Blackwell Publishing, Inc
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.070432

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