Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires

Autores
Japas, M.S.; Sellés-Martinez, J.
Año de publicación
1998
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
knowledge of the initial shape of strain markers allows calculation of the strain ellipsoid (axial relationships and orientation) when they show distorted geometries after deformation. This information is usually combined with the analysis of other micro- and mesostructures that constitute the dynamic framework in which the whole assemblage of structures developed. If only one deformational episode was responsible for all of them, the result is a highly coherent picture. In this paper, the quantification of strain and orientation of strain axes, is attempted on the basis of distorted hexagonal columns cropping out close to Puesto El Malabar (Pigüé, Sierras Australes de Buenos Aires). This columnar strucutre occurs in rhyolitic flows and tuffs of the Precambrian (?) basement in the area. It is apparent from this study that deformation in the central part of the north-western arc of Sierras Australes is markedly heterogeneous at all scales, with axial relationships giving values that record a variationin between almost no deformation and belts of high strain in which cleavage erases all evidence of columnar jointing. Micro- and mesostructural analysis shows dextral simple shear in plan view, oriented Az.145°-150° , and E-W stripes of sinistral shear that appear to be later and fewer than the earlier, one. Evidence of shear to the NE in vertical section has been found that is also heterogeneously developed. Secondary microstructures also show geometric relationships that are coherent with the general picture in the area. The regional significance of these data is analyzed in the regional picture, and it is concluded that it fits the previous model of an arcuate belt resulting from local development of conjugate megashears, with E-W (sinistral) and SW-NE (dextral) bands shaping the arc. © 1998 Asociación Geológica Argentina.
Fil:Japas, M.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Sellés-Martinez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fuente
Rev. Asoc. Geol. Argent. 1998;53(3):317-324
Materia
basement rock
deformation
rock microstructure
strain analysis
Argentina
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/2.5/ar
Repositorio
Biblioteca Digital (UBA-FCEN)
Institución
Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
OAI Identificador
paperaa:paper_00044822_v53_n3_p317_Japas

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repository_id_str 1896
network_name_str Biblioteca Digital (UBA-FCEN)
spelling Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires Japas, M.S.Sellés-Martinez, J.basement rockdeformationrock microstructurestrain analysisArgentinaknowledge of the initial shape of strain markers allows calculation of the strain ellipsoid (axial relationships and orientation) when they show distorted geometries after deformation. This information is usually combined with the analysis of other micro- and mesostructures that constitute the dynamic framework in which the whole assemblage of structures developed. If only one deformational episode was responsible for all of them, the result is a highly coherent picture. In this paper, the quantification of strain and orientation of strain axes, is attempted on the basis of distorted hexagonal columns cropping out close to Puesto El Malabar (Pigüé, Sierras Australes de Buenos Aires). This columnar strucutre occurs in rhyolitic flows and tuffs of the Precambrian (?) basement in the area. It is apparent from this study that deformation in the central part of the north-western arc of Sierras Australes is markedly heterogeneous at all scales, with axial relationships giving values that record a variationin between almost no deformation and belts of high strain in which cleavage erases all evidence of columnar jointing. Micro- and mesostructural analysis shows dextral simple shear in plan view, oriented Az.145°-150° , and E-W stripes of sinistral shear that appear to be later and fewer than the earlier, one. Evidence of shear to the NE in vertical section has been found that is also heterogeneously developed. Secondary microstructures also show geometric relationships that are coherent with the general picture in the area. The regional significance of these data is analyzed in the regional picture, and it is concluded that it fits the previous model of an arcuate belt resulting from local development of conjugate megashears, with E-W (sinistral) and SW-NE (dextral) bands shaping the arc. © 1998 Asociación Geológica Argentina.Fil:Japas, M.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Sellés-Martinez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.1998info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://hdl.handle.net/20.500.12110/paper_00044822_v53_n3_p317_JapasRev. Asoc. Geol. Argent. 1998;53(3):317-324reponame:Biblioteca Digital (UBA-FCEN)instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesinstacron:UBA-FCENenginfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/2.5/ar2025-09-29T13:43:09Zpaperaa:paper_00044822_v53_n3_p317_JapasInstitucionalhttps://digital.bl.fcen.uba.ar/Universidad públicaNo correspondehttps://digital.bl.fcen.uba.ar/cgi-bin/oaiserver.cgiana@bl.fcen.uba.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:18962025-09-29 13:43:10.484Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesfalse
dc.title.none.fl_str_mv Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
title Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
spellingShingle Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
Japas, M.S.
basement rock
deformation
rock microstructure
strain analysis
Argentina
title_short Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
title_full Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
title_fullStr Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
title_full_unstemmed Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
title_sort Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
dc.creator.none.fl_str_mv Japas, M.S.
Sellés-Martinez, J.
author Japas, M.S.
author_facet Japas, M.S.
Sellés-Martinez, J.
author_role author
author2 Sellés-Martinez, J.
author2_role author
dc.subject.none.fl_str_mv basement rock
deformation
rock microstructure
strain analysis
Argentina
topic basement rock
deformation
rock microstructure
strain analysis
Argentina
dc.description.none.fl_txt_mv knowledge of the initial shape of strain markers allows calculation of the strain ellipsoid (axial relationships and orientation) when they show distorted geometries after deformation. This information is usually combined with the analysis of other micro- and mesostructures that constitute the dynamic framework in which the whole assemblage of structures developed. If only one deformational episode was responsible for all of them, the result is a highly coherent picture. In this paper, the quantification of strain and orientation of strain axes, is attempted on the basis of distorted hexagonal columns cropping out close to Puesto El Malabar (Pigüé, Sierras Australes de Buenos Aires). This columnar strucutre occurs in rhyolitic flows and tuffs of the Precambrian (?) basement in the area. It is apparent from this study that deformation in the central part of the north-western arc of Sierras Australes is markedly heterogeneous at all scales, with axial relationships giving values that record a variationin between almost no deformation and belts of high strain in which cleavage erases all evidence of columnar jointing. Micro- and mesostructural analysis shows dextral simple shear in plan view, oriented Az.145°-150° , and E-W stripes of sinistral shear that appear to be later and fewer than the earlier, one. Evidence of shear to the NE in vertical section has been found that is also heterogeneously developed. Secondary microstructures also show geometric relationships that are coherent with the general picture in the area. The regional significance of these data is analyzed in the regional picture, and it is concluded that it fits the previous model of an arcuate belt resulting from local development of conjugate megashears, with E-W (sinistral) and SW-NE (dextral) bands shaping the arc. © 1998 Asociación Geológica Argentina.
Fil:Japas, M.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Sellés-Martinez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
description knowledge of the initial shape of strain markers allows calculation of the strain ellipsoid (axial relationships and orientation) when they show distorted geometries after deformation. This information is usually combined with the analysis of other micro- and mesostructures that constitute the dynamic framework in which the whole assemblage of structures developed. If only one deformational episode was responsible for all of them, the result is a highly coherent picture. In this paper, the quantification of strain and orientation of strain axes, is attempted on the basis of distorted hexagonal columns cropping out close to Puesto El Malabar (Pigüé, Sierras Australes de Buenos Aires). This columnar strucutre occurs in rhyolitic flows and tuffs of the Precambrian (?) basement in the area. It is apparent from this study that deformation in the central part of the north-western arc of Sierras Australes is markedly heterogeneous at all scales, with axial relationships giving values that record a variationin between almost no deformation and belts of high strain in which cleavage erases all evidence of columnar jointing. Micro- and mesostructural analysis shows dextral simple shear in plan view, oriented Az.145°-150° , and E-W stripes of sinistral shear that appear to be later and fewer than the earlier, one. Evidence of shear to the NE in vertical section has been found that is also heterogeneously developed. Secondary microstructures also show geometric relationships that are coherent with the general picture in the area. The regional significance of these data is analyzed in the regional picture, and it is concluded that it fits the previous model of an arcuate belt resulting from local development of conjugate megashears, with E-W (sinistral) and SW-NE (dextral) bands shaping the arc. © 1998 Asociación Geológica Argentina.
publishDate 1998
dc.date.none.fl_str_mv 1998
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/20.500.12110/paper_00044822_v53_n3_p317_Japas
url http://hdl.handle.net/20.500.12110/paper_00044822_v53_n3_p317_Japas
dc.language.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
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eu_rights_str_mv openAccess
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dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv Rev. Asoc. Geol. Argent. 1998;53(3):317-324
reponame:Biblioteca Digital (UBA-FCEN)
instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron:UBA-FCEN
reponame_str Biblioteca Digital (UBA-FCEN)
collection Biblioteca Digital (UBA-FCEN)
instname_str Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron_str UBA-FCEN
institution UBA-FCEN
repository.name.fl_str_mv Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
repository.mail.fl_str_mv ana@bl.fcen.uba.ar
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