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

Mostrar todas las versiones(3)

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 dynam...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Japas, M.S., Sellés-Martinez, J.
Formato: Artículo publishedVersion
Publicado: 1998
Materias:
basement rock
deformation
rock microstructure
strain analysis
Argentina
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00044822_v53_n3_p317_Japas
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v53_n3_p317_Japas_oai
Aporte de:
Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires
id I28-R145-paper_00044822_v53_n3_p317_Japas_oai
record_format dspace
spelling I28-R145-paper_00044822_v53_n3_p317_Japas_oai2024-08-16 Japas, M.S. Sellés-Martinez, J. 1998 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. application/pdf http://hdl.handle.net/20.500.12110/paper_00044822_v53_n3_p317_Japas info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Rev. Asoc. Geol. Argent. 1998;53(3):317-324 basement rock deformation rock microstructure strain analysis Argentina Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v53_n3_p317_Japas_oai
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-145
collection Repositorio Digital de la Universidad de Buenos Aires (UBA)
topic basement rock
deformation
rock microstructure
strain analysis
Argentina
spellingShingle basement rock
deformation
rock microstructure
strain analysis
Argentina
Japas, M.S.
Sellés-Martinez, J.
Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
topic_facet basement rock
deformation
rock microstructure
strain analysis
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.
format Artículo
Artículo
publishedVersion
author Japas, M.S.
Sellés-Martinez, J.
author_facet Japas, M.S.
Sellés-Martinez, J.
author_sort Japas, M.S.
title Analysis of strained microfabrics in the "Porfidos Rioliticos". Basement area of Pigüe, Sierras Australes de Buenos Aires
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
publishDate 1998
url http://hdl.handle.net/20.500.12110/paper_00044822_v53_n3_p317_Japas
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v53_n3_p317_Japas_oai
work_keys_str_mv AT japasms analysisofstrainedmicrofabricsintheporfidosrioliticosbasementareaofpiguesierrasaustralesdebuenosaires
AT sellesmartinezj analysisofstrainedmicrofabricsintheporfidosrioliticosbasementareaofpiguesierrasaustralesdebuenosaires
_version_ 1809356850417631232

Ejemplares similares