Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires

Autores
Fortunatti, Natalia Beatriz; Delpino, Sergio Hugo; Dimieri, Luis Vicente
Año de publicación
2001
Idioma
español castellano
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The Sierras Australes fold-and-thrust-belt is located southwest of the Buenos Aires province, Argentina. The chain is composed of a precambrian basement overlied by a middle to upper palaeozoic metasedimentary sequence, and surrounded by tertiary and quaternary deposits. A preliminary microestructural analysis was carried on rocks of the Napostá Formation (orthoquartzites, Ventana Group). A systematic sampling on a section located south to the Abra de la Ventana locality, was performed. Samples were collected in several positions within a key bed that shows the typical style of folding in the sierras: extended normal limbs (SW) and refolded short limbs (NE). The main observations are: 1) In function of the sample locations within the folded bed, the rock shows different rheologic behaviour: normal extended limbs are less deformed showing protomylonitic textures with preservation of a great proportion of relictic grains, scarce recrystallized matrix and neoformed sericite; intensely deformed refolded short limbs show mylonitic textures with flattened and strongly recrystallized relict grains, surrounded by a matrix composed of fine recrystallized quartz grains and sericite. Samples cióse to fold hinges, show more intense mylonitization than those of theneighbouring limbs; 2) Evidences of dynamic recrystallization, involving both grain boundary migration and subgrain rotation mechanisms, have been observed. Grain size reduction took place in a transition between régimen 2 and 3, in the temperature range 250° to 300°C. Presence of fluids during mylonitization is documented by textura] evidences of pressure solution and associated mass transfer mechanisms (straight quartz crystal faces parallel to foliation and new-crystallization of sericite-muscovite in folias and pressure shadows).
Fil: Fortunatti, Natalia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
Fil: Delpino, Sergio Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
Fil: Dimieri, Luis Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
Materia
SIERRAS AUSTRALES
MICROESTRUCTURAS
DEFORMACION
GRUPO VENTANA
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:11336/81301
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/81301
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos AiresPreliminary análisis of infernal deformation on Napostá Formation quartzites, Ventana Group, Sierras Australes of Buenos AiresFortunatti, Natalia BeatrizDelpino, Sergio HugoDimieri, Luis VicenteSIERRAS AUSTRALESMICROESTRUCTURASDEFORMACIONGRUPO VENTANAhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1The Sierras Australes fold-and-thrust-belt is located southwest of the Buenos Aires province, Argentina. The chain is composed of a precambrian basement overlied by a middle to upper palaeozoic metasedimentary sequence, and surrounded by tertiary and quaternary deposits. A preliminary microestructural analysis was carried on rocks of the Napostá Formation (orthoquartzites, Ventana Group). A systematic sampling on a section located south to the Abra de la Ventana locality, was performed. Samples were collected in several positions within a key bed that shows the typical style of folding in the sierras: extended normal limbs (SW) and refolded short limbs (NE). The main observations are: 1) In function of the sample locations within the folded bed, the rock shows different rheologic behaviour: normal extended limbs are less deformed showing protomylonitic textures with preservation of a great proportion of relictic grains, scarce recrystallized matrix and neoformed sericite; intensely deformed refolded short limbs show mylonitic textures with flattened and strongly recrystallized relict grains, surrounded by a matrix composed of fine recrystallized quartz grains and sericite. Samples cióse to fold hinges, show more intense mylonitization than those of theneighbouring limbs; 2) Evidences of dynamic recrystallization, involving both grain boundary migration and subgrain rotation mechanisms, have been observed. Grain size reduction took place in a transition between régimen 2 and 3, in the temperature range 250° to 300°C. Presence of fluids during mylonitization is documented by textura] evidences of pressure solution and associated mass transfer mechanisms (straight quartz crystal faces parallel to foliation and new-crystallization of sericite-muscovite in folias and pressure shadows).Fil: Fortunatti, Natalia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Delpino, Sergio Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Dimieri, Luis Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaAsociación Geológica Argentina2001-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/81301Fortunatti, Natalia Beatriz; Delpino, Sergio Hugo; Dimieri, Luis Vicente; Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires; Asociación Geológica Argentina; Revista de la Asociación Geológica Argentina. Serie D. Publicación especial; 5; 12-2001; 89-950328-2767CONICET DigitalCONICETspainfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:44:52Zoai:ri.conicet.gov.ar:11336/81301instacron: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 10:44:53.228CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
Preliminary análisis of infernal deformation on Napostá Formation quartzites, Ventana Group, Sierras Australes of Buenos Aires
title Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
spellingShingle Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
Fortunatti, Natalia Beatriz
SIERRAS AUSTRALES
MICROESTRUCTURAS
DEFORMACION
GRUPO VENTANA
title_short Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
title_full Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
title_fullStr Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
title_full_unstemmed Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
title_sort Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires
dc.creator.none.fl_str_mv Fortunatti, Natalia Beatriz
Delpino, Sergio Hugo
Dimieri, Luis Vicente
author Fortunatti, Natalia Beatriz
author_facet Fortunatti, Natalia Beatriz
Delpino, Sergio Hugo
Dimieri, Luis Vicente
author_role author
author2 Delpino, Sergio Hugo
Dimieri, Luis Vicente
author2_role author
author
dc.subject.none.fl_str_mv SIERRAS AUSTRALES
MICROESTRUCTURAS
DEFORMACION
GRUPO VENTANA
topic SIERRAS AUSTRALES
MICROESTRUCTURAS
DEFORMACION
GRUPO VENTANA
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 Sierras Australes fold-and-thrust-belt is located southwest of the Buenos Aires province, Argentina. The chain is composed of a precambrian basement overlied by a middle to upper palaeozoic metasedimentary sequence, and surrounded by tertiary and quaternary deposits. A preliminary microestructural analysis was carried on rocks of the Napostá Formation (orthoquartzites, Ventana Group). A systematic sampling on a section located south to the Abra de la Ventana locality, was performed. Samples were collected in several positions within a key bed that shows the typical style of folding in the sierras: extended normal limbs (SW) and refolded short limbs (NE). The main observations are: 1) In function of the sample locations within the folded bed, the rock shows different rheologic behaviour: normal extended limbs are less deformed showing protomylonitic textures with preservation of a great proportion of relictic grains, scarce recrystallized matrix and neoformed sericite; intensely deformed refolded short limbs show mylonitic textures with flattened and strongly recrystallized relict grains, surrounded by a matrix composed of fine recrystallized quartz grains and sericite. Samples cióse to fold hinges, show more intense mylonitization than those of theneighbouring limbs; 2) Evidences of dynamic recrystallization, involving both grain boundary migration and subgrain rotation mechanisms, have been observed. Grain size reduction took place in a transition between régimen 2 and 3, in the temperature range 250° to 300°C. Presence of fluids during mylonitization is documented by textura] evidences of pressure solution and associated mass transfer mechanisms (straight quartz crystal faces parallel to foliation and new-crystallization of sericite-muscovite in folias and pressure shadows).
Fil: Fortunatti, Natalia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
Fil: Delpino, Sergio Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
Fil: Dimieri, Luis Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina
description The Sierras Australes fold-and-thrust-belt is located southwest of the Buenos Aires province, Argentina. The chain is composed of a precambrian basement overlied by a middle to upper palaeozoic metasedimentary sequence, and surrounded by tertiary and quaternary deposits. A preliminary microestructural analysis was carried on rocks of the Napostá Formation (orthoquartzites, Ventana Group). A systematic sampling on a section located south to the Abra de la Ventana locality, was performed. Samples were collected in several positions within a key bed that shows the typical style of folding in the sierras: extended normal limbs (SW) and refolded short limbs (NE). The main observations are: 1) In function of the sample locations within the folded bed, the rock shows different rheologic behaviour: normal extended limbs are less deformed showing protomylonitic textures with preservation of a great proportion of relictic grains, scarce recrystallized matrix and neoformed sericite; intensely deformed refolded short limbs show mylonitic textures with flattened and strongly recrystallized relict grains, surrounded by a matrix composed of fine recrystallized quartz grains and sericite. Samples cióse to fold hinges, show more intense mylonitization than those of theneighbouring limbs; 2) Evidences of dynamic recrystallization, involving both grain boundary migration and subgrain rotation mechanisms, have been observed. Grain size reduction took place in a transition between régimen 2 and 3, in the temperature range 250° to 300°C. Presence of fluids during mylonitization is documented by textura] evidences of pressure solution and associated mass transfer mechanisms (straight quartz crystal faces parallel to foliation and new-crystallization of sericite-muscovite in folias and pressure shadows).
publishDate 2001
dc.date.none.fl_str_mv 2001-12
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/11336/81301
Fortunatti, Natalia Beatriz; Delpino, Sergio Hugo; Dimieri, Luis Vicente; Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires; Asociación Geológica Argentina; Revista de la Asociación Geológica Argentina. Serie D. Publicación especial; 5; 12-2001; 89-95
0328-2767
CONICET Digital
CONICET
url http://hdl.handle.net/11336/81301
identifier_str_mv Fortunatti, Natalia Beatriz; Delpino, Sergio Hugo; Dimieri, Luis Vicente; Análisis preliminar de la deformación interna en cuarcitas de la Formación Napostá, Grupo Ventana, Sierras Australes de Buenos Aires; Asociación Geológica Argentina; Revista de la Asociación Geológica Argentina. Serie D. Publicación especial; 5; 12-2001; 89-95
0328-2767
CONICET Digital
CONICET
dc.language.none.fl_str_mv spa
language spa
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
dc.publisher.none.fl_str_mv Asociación Geológica Argentina
publisher.none.fl_str_mv Asociación Geológica Argentina
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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