The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry

Autores
Zaffarana, Claudia Beatriz; Somoza, Ruben; Lopez, Monica Graciela
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The Late Triassic Central Patagonian Batholith is a key element in paleogeographic models of West Gondwana just before to the break-up of the supercontinent. The preexisting classification of units of this batholith was mainly based on isotopic and geochemical data. Here we report the results of field mapping and petrography, backed up by three new 40Ar/39Ar biotite ages, which reveal previously unnoticed relationships of the rocks in the batholith. Based on the new information we present a reorganization of units where the batholith is primarily formed by the Gastre and the Lipetren superunits. The Gastre Superunit is the oldest magmatic suite and is composed of I-type granites which display evidence of felsic and mafic magma interaction. It is formed by 4 second-order units: 1) equigranular hornblende ebiotite granodiorites, 2) porphyritic biotiteehornblende monzogranites, 3) equigranular biotitic monzogranites and 4) hornblende quartz-diorites. Emplacement depth of the Gastre Superunit is bracketed between 6 and 11 km (1.8e3 kbar), and the maximum recorded temperatures of emplacement are comprised between 660 and 800 C. The recalculated Rb/Sr age is 222 ± 3 Ma and the porphyritic biotite ehornblende monzogranites yielded a 40Ar/39Ar age in biotite of 213 ± 5 Ma. On the other hand, the Lipetren Superunit is made up by fine-grained biotitic monzo- and syenogranites that postdate magma hybridization processes and intrude all the other units. The recalculated Rb/Sr age for this suite is identical to a 40Ar/39Ar age in biotite extracted from one of its monzogranites (206.4 ± 5.3 and 206 ± 4 Ma, respectively). This and the observed textural features suggest very fast cooling related to a subvolcanic emplacement. An independent unit, the “Horqueta Granodiorite”, which has previously been considered as the record of a Jurassic intrusive stage in the Central Patagonian Batholith, gave a 40Ar/39Ar age in biotite of 214 ± 2 Ma. This and the reexamination of available isotopic data allow propose that this granodiorite unit is part of the Late Paleozoic intrusives in the region. The Late Triassic Central Patagonian Batholith is overlain by 190e185 Ma volcano-sedimentary rocks, suggesting that it was exposed sometime between the latest Triassic and earliest Jurassic times, roughly coeval with a major accretionary episode in the southwestern margin of Gondwana.
Fil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Somoza, Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Lopez, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; Argentina
Materia
Hybridization
Ar-Ar Cooling Ages
Thermobarometry
Central Patagonia Batholith
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/18317

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network_name_str CONICET Digital (CONICET)
spelling The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometryZaffarana, Claudia BeatrizSomoza, RubenLopez, Monica GracielaHybridizationAr-Ar Cooling AgesThermobarometryCentral Patagonia Batholithhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1The Late Triassic Central Patagonian Batholith is a key element in paleogeographic models of West Gondwana just before to the break-up of the supercontinent. The preexisting classification of units of this batholith was mainly based on isotopic and geochemical data. Here we report the results of field mapping and petrography, backed up by three new 40Ar/39Ar biotite ages, which reveal previously unnoticed relationships of the rocks in the batholith. Based on the new information we present a reorganization of units where the batholith is primarily formed by the Gastre and the Lipetren superunits. The Gastre Superunit is the oldest magmatic suite and is composed of I-type granites which display evidence of felsic and mafic magma interaction. It is formed by 4 second-order units: 1) equigranular hornblende ebiotite granodiorites, 2) porphyritic biotiteehornblende monzogranites, 3) equigranular biotitic monzogranites and 4) hornblende quartz-diorites. Emplacement depth of the Gastre Superunit is bracketed between 6 and 11 km (1.8e3 kbar), and the maximum recorded temperatures of emplacement are comprised between 660 and 800 C. The recalculated Rb/Sr age is 222 ± 3 Ma and the porphyritic biotite ehornblende monzogranites yielded a 40Ar/39Ar age in biotite of 213 ± 5 Ma. On the other hand, the Lipetren Superunit is made up by fine-grained biotitic monzo- and syenogranites that postdate magma hybridization processes and intrude all the other units. The recalculated Rb/Sr age for this suite is identical to a 40Ar/39Ar age in biotite extracted from one of its monzogranites (206.4 ± 5.3 and 206 ± 4 Ma, respectively). This and the observed textural features suggest very fast cooling related to a subvolcanic emplacement. An independent unit, the “Horqueta Granodiorite”, which has previously been considered as the record of a Jurassic intrusive stage in the Central Patagonian Batholith, gave a 40Ar/39Ar age in biotite of 214 ± 2 Ma. This and the reexamination of available isotopic data allow propose that this granodiorite unit is part of the Late Paleozoic intrusives in the region. The Late Triassic Central Patagonian Batholith is overlain by 190e185 Ma volcano-sedimentary rocks, suggesting that it was exposed sometime between the latest Triassic and earliest Jurassic times, roughly coeval with a major accretionary episode in the southwestern margin of Gondwana.Fil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Somoza, Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Lopez, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; ArgentinaElsevier2014-11info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/18317Zaffarana, Claudia Beatriz; Somoza, Ruben; Lopez, Monica Graciela; The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry; Elsevier; Journal Of South American Earth Sciences; 55; 11-2014; 94-1220895-9811CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1016/j.jsames.2014.06.006info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0895981114000704?via%3Dihubinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-nd/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:55:03Zoai:ri.conicet.gov.ar:11336/18317instacron: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:34982025-09-03 09:55:04.159CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
title The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
spellingShingle The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
Zaffarana, Claudia Beatriz
Hybridization
Ar-Ar Cooling Ages
Thermobarometry
Central Patagonia Batholith
title_short The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
title_full The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
title_fullStr The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
title_full_unstemmed The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
title_sort The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry
dc.creator.none.fl_str_mv Zaffarana, Claudia Beatriz
Somoza, Ruben
Lopez, Monica Graciela
author Zaffarana, Claudia Beatriz
author_facet Zaffarana, Claudia Beatriz
Somoza, Ruben
Lopez, Monica Graciela
author_role author
author2 Somoza, Ruben
Lopez, Monica Graciela
author2_role author
author
dc.subject.none.fl_str_mv Hybridization
Ar-Ar Cooling Ages
Thermobarometry
Central Patagonia Batholith
topic Hybridization
Ar-Ar Cooling Ages
Thermobarometry
Central Patagonia Batholith
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv The Late Triassic Central Patagonian Batholith is a key element in paleogeographic models of West Gondwana just before to the break-up of the supercontinent. The preexisting classification of units of this batholith was mainly based on isotopic and geochemical data. Here we report the results of field mapping and petrography, backed up by three new 40Ar/39Ar biotite ages, which reveal previously unnoticed relationships of the rocks in the batholith. Based on the new information we present a reorganization of units where the batholith is primarily formed by the Gastre and the Lipetren superunits. The Gastre Superunit is the oldest magmatic suite and is composed of I-type granites which display evidence of felsic and mafic magma interaction. It is formed by 4 second-order units: 1) equigranular hornblende ebiotite granodiorites, 2) porphyritic biotiteehornblende monzogranites, 3) equigranular biotitic monzogranites and 4) hornblende quartz-diorites. Emplacement depth of the Gastre Superunit is bracketed between 6 and 11 km (1.8e3 kbar), and the maximum recorded temperatures of emplacement are comprised between 660 and 800 C. The recalculated Rb/Sr age is 222 ± 3 Ma and the porphyritic biotite ehornblende monzogranites yielded a 40Ar/39Ar age in biotite of 213 ± 5 Ma. On the other hand, the Lipetren Superunit is made up by fine-grained biotitic monzo- and syenogranites that postdate magma hybridization processes and intrude all the other units. The recalculated Rb/Sr age for this suite is identical to a 40Ar/39Ar age in biotite extracted from one of its monzogranites (206.4 ± 5.3 and 206 ± 4 Ma, respectively). This and the observed textural features suggest very fast cooling related to a subvolcanic emplacement. An independent unit, the “Horqueta Granodiorite”, which has previously been considered as the record of a Jurassic intrusive stage in the Central Patagonian Batholith, gave a 40Ar/39Ar age in biotite of 214 ± 2 Ma. This and the reexamination of available isotopic data allow propose that this granodiorite unit is part of the Late Paleozoic intrusives in the region. The Late Triassic Central Patagonian Batholith is overlain by 190e185 Ma volcano-sedimentary rocks, suggesting that it was exposed sometime between the latest Triassic and earliest Jurassic times, roughly coeval with a major accretionary episode in the southwestern margin of Gondwana.
Fil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Somoza, Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Lopez, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; Argentina
description The Late Triassic Central Patagonian Batholith is a key element in paleogeographic models of West Gondwana just before to the break-up of the supercontinent. The preexisting classification of units of this batholith was mainly based on isotopic and geochemical data. Here we report the results of field mapping and petrography, backed up by three new 40Ar/39Ar biotite ages, which reveal previously unnoticed relationships of the rocks in the batholith. Based on the new information we present a reorganization of units where the batholith is primarily formed by the Gastre and the Lipetren superunits. The Gastre Superunit is the oldest magmatic suite and is composed of I-type granites which display evidence of felsic and mafic magma interaction. It is formed by 4 second-order units: 1) equigranular hornblende ebiotite granodiorites, 2) porphyritic biotiteehornblende monzogranites, 3) equigranular biotitic monzogranites and 4) hornblende quartz-diorites. Emplacement depth of the Gastre Superunit is bracketed between 6 and 11 km (1.8e3 kbar), and the maximum recorded temperatures of emplacement are comprised between 660 and 800 C. The recalculated Rb/Sr age is 222 ± 3 Ma and the porphyritic biotite ehornblende monzogranites yielded a 40Ar/39Ar age in biotite of 213 ± 5 Ma. On the other hand, the Lipetren Superunit is made up by fine-grained biotitic monzo- and syenogranites that postdate magma hybridization processes and intrude all the other units. The recalculated Rb/Sr age for this suite is identical to a 40Ar/39Ar age in biotite extracted from one of its monzogranites (206.4 ± 5.3 and 206 ± 4 Ma, respectively). This and the observed textural features suggest very fast cooling related to a subvolcanic emplacement. An independent unit, the “Horqueta Granodiorite”, which has previously been considered as the record of a Jurassic intrusive stage in the Central Patagonian Batholith, gave a 40Ar/39Ar age in biotite of 214 ± 2 Ma. This and the reexamination of available isotopic data allow propose that this granodiorite unit is part of the Late Paleozoic intrusives in the region. The Late Triassic Central Patagonian Batholith is overlain by 190e185 Ma volcano-sedimentary rocks, suggesting that it was exposed sometime between the latest Triassic and earliest Jurassic times, roughly coeval with a major accretionary episode in the southwestern margin of Gondwana.
publishDate 2014
dc.date.none.fl_str_mv 2014-11
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/11336/18317
Zaffarana, Claudia Beatriz; Somoza, Ruben; Lopez, Monica Graciela; The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry; Elsevier; Journal Of South American Earth Sciences; 55; 11-2014; 94-122
0895-9811
CONICET Digital
CONICET
url http://hdl.handle.net/11336/18317
identifier_str_mv Zaffarana, Claudia Beatriz; Somoza, Ruben; Lopez, Monica Graciela; The Late Triassic Central Patagonian Batholith: Magma hybridization, 40Ar/39Ar ages and thermobarometry; Elsevier; Journal Of South American Earth Sciences; 55; 11-2014; 94-122
0895-9811
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jsames.2014.06.006
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0895981114000704?via%3Dihub
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
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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