One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina

Autores
Finch, M. A.; Weinberg, R. F.; Fuentes, María Gabriela; Hasalová, P.; Becchio, Raul Alberto
Año de publicación
2015
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We describe a 1 km-thick ultramylonite forming the high strain base of the >3.5 km-thick El Pichao shear zone in the Sierra de Quilmes. This shear zone thrusted granulite facies migmatites onto amphibolite facies rocks during the 470 Ma Famatinian orogeny. Strain grades upwards from ultramylonites to weakly sheared migmatites across the 3.5 km-zone and the mylonitic rocks define a geochemical field narrower than the protolith, suggesting they underwent mixing and homogenization through shearing. Ultramylonites this thick are uncommon. The width of a shear zone, in the absence of significant compositional rheological contrasts controlling strain localization, is controlled by the balance between shear heat generation and diffusion. Under typical crustal conditions a strain rate of 10−12 s−1 is required to form a 1 km-thick ultramylonite, and this is achieved when large movement velocities are imposed across the shear zone. We postulate that the El Pichao shear zone and its thick ultramylonite accommodated a significant fraction of convergence velocities driving the orogeny, and that the wide mylonitic shear zones characteristic of the Cambrian–Ordovician deformation of the Sierras Pampeanas result from the convergent movement being taken up by only a few active major shear zones.
Fil: Finch, M. A.. Monash University; Australia
Fil: Weinberg, R. F.. Monash University; Australia
Fil: Fuentes, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina
Fil: Hasalová, P.. Monash University; Australia
Fil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina
Materia
Ultramylonite
Sierra de Quilmes
Sierras Pampeanas
Famatinian Orogeny
Shear Zone Width
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:11336/22146
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/22146
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW ArgentinaFinch, M. A.Weinberg, R. F.Fuentes, María GabrielaHasalová, P.Becchio, Raul AlbertoUltramyloniteSierra de QuilmesSierras PampeanasFamatinian OrogenyShear Zone Widthhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1We describe a 1 km-thick ultramylonite forming the high strain base of the >3.5 km-thick El Pichao shear zone in the Sierra de Quilmes. This shear zone thrusted granulite facies migmatites onto amphibolite facies rocks during the 470 Ma Famatinian orogeny. Strain grades upwards from ultramylonites to weakly sheared migmatites across the 3.5 km-zone and the mylonitic rocks define a geochemical field narrower than the protolith, suggesting they underwent mixing and homogenization through shearing. Ultramylonites this thick are uncommon. The width of a shear zone, in the absence of significant compositional rheological contrasts controlling strain localization, is controlled by the balance between shear heat generation and diffusion. Under typical crustal conditions a strain rate of 10−12 s−1 is required to form a 1 km-thick ultramylonite, and this is achieved when large movement velocities are imposed across the shear zone. We postulate that the El Pichao shear zone and its thick ultramylonite accommodated a significant fraction of convergence velocities driving the orogeny, and that the wide mylonitic shear zones characteristic of the Cambrian–Ordovician deformation of the Sierras Pampeanas result from the convergent movement being taken up by only a few active major shear zones.Fil: Finch, M. A.. Monash University; AustraliaFil: Weinberg, R. F.. Monash University; AustraliaFil: Fuentes, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; ArgentinaFil: Hasalová, P.. Monash University; AustraliaFil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; ArgentinaElsevier2015-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/22146Finch, M. A.; Weinberg, R. F.; Fuentes, María Gabriela; Hasalová, P.; Becchio, Raul Alberto; One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina; Elsevier; Journal Of Structural Geology; 72; 1-2015; 33-540191-8141CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1016/j.jsg.2015.01.002info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0191814115000036info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-nd/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T10:01:06Zoai:ri.conicet.gov.ar:11336/22146instacron: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 10:01:06.819CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
title One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
spellingShingle One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
Finch, M. A.
Ultramylonite
Sierra de Quilmes
Sierras Pampeanas
Famatinian Orogeny
Shear Zone Width
title_short One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
title_full One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
title_fullStr One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
title_full_unstemmed One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
title_sort One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina
dc.creator.none.fl_str_mv Finch, M. A.
Weinberg, R. F.
Fuentes, María Gabriela
Hasalová, P.
Becchio, Raul Alberto
author Finch, M. A.
author_facet Finch, M. A.
Weinberg, R. F.
Fuentes, María Gabriela
Hasalová, P.
Becchio, Raul Alberto
author_role author
author2 Weinberg, R. F.
Fuentes, María Gabriela
Hasalová, P.
Becchio, Raul Alberto
author2_role author
author
author
author
dc.subject.none.fl_str_mv Ultramylonite
Sierra de Quilmes
Sierras Pampeanas
Famatinian Orogeny
Shear Zone Width
topic Ultramylonite
Sierra de Quilmes
Sierras Pampeanas
Famatinian Orogeny
Shear Zone Width
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv We describe a 1 km-thick ultramylonite forming the high strain base of the >3.5 km-thick El Pichao shear zone in the Sierra de Quilmes. This shear zone thrusted granulite facies migmatites onto amphibolite facies rocks during the 470 Ma Famatinian orogeny. Strain grades upwards from ultramylonites to weakly sheared migmatites across the 3.5 km-zone and the mylonitic rocks define a geochemical field narrower than the protolith, suggesting they underwent mixing and homogenization through shearing. Ultramylonites this thick are uncommon. The width of a shear zone, in the absence of significant compositional rheological contrasts controlling strain localization, is controlled by the balance between shear heat generation and diffusion. Under typical crustal conditions a strain rate of 10−12 s−1 is required to form a 1 km-thick ultramylonite, and this is achieved when large movement velocities are imposed across the shear zone. We postulate that the El Pichao shear zone and its thick ultramylonite accommodated a significant fraction of convergence velocities driving the orogeny, and that the wide mylonitic shear zones characteristic of the Cambrian–Ordovician deformation of the Sierras Pampeanas result from the convergent movement being taken up by only a few active major shear zones.
Fil: Finch, M. A.. Monash University; Australia
Fil: Weinberg, R. F.. Monash University; Australia
Fil: Fuentes, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina
Fil: Hasalová, P.. Monash University; Australia
Fil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentina
description We describe a 1 km-thick ultramylonite forming the high strain base of the >3.5 km-thick El Pichao shear zone in the Sierra de Quilmes. This shear zone thrusted granulite facies migmatites onto amphibolite facies rocks during the 470 Ma Famatinian orogeny. Strain grades upwards from ultramylonites to weakly sheared migmatites across the 3.5 km-zone and the mylonitic rocks define a geochemical field narrower than the protolith, suggesting they underwent mixing and homogenization through shearing. Ultramylonites this thick are uncommon. The width of a shear zone, in the absence of significant compositional rheological contrasts controlling strain localization, is controlled by the balance between shear heat generation and diffusion. Under typical crustal conditions a strain rate of 10−12 s−1 is required to form a 1 km-thick ultramylonite, and this is achieved when large movement velocities are imposed across the shear zone. We postulate that the El Pichao shear zone and its thick ultramylonite accommodated a significant fraction of convergence velocities driving the orogeny, and that the wide mylonitic shear zones characteristic of the Cambrian–Ordovician deformation of the Sierras Pampeanas result from the convergent movement being taken up by only a few active major shear zones.
publishDate 2015
dc.date.none.fl_str_mv 2015-01
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/11336/22146
Finch, M. A.; Weinberg, R. F.; Fuentes, María Gabriela; Hasalová, P.; Becchio, Raul Alberto; One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina; Elsevier; Journal Of Structural Geology; 72; 1-2015; 33-54
0191-8141
CONICET Digital
CONICET
url http://hdl.handle.net/11336/22146
identifier_str_mv Finch, M. A.; Weinberg, R. F.; Fuentes, María Gabriela; Hasalová, P.; Becchio, Raul Alberto; One kilometre-thick ultramylonite, Sierra de Quilmes, Sierras Pampeanas, NW Argentina; Elsevier; Journal Of Structural Geology; 72; 1-2015; 33-54
0191-8141
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.jsg.2015.01.002
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0191814115000036
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
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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score 13.13397

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