Towards the definition of AMS facies in the deposits of pyroclastic density currents

Autores
Ort, M. H.; Newkirk, T.; Vilas, Juan Francisco A.; Vazquez, J. A.
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate-strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.
Fil: Ort, M. H.. Northern Arizona University; Estados Unidos
Fil: Newkirk, T.. University of British Columbia; Canadá
Fil: Vilas, Juan Francisco A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Vazquez, J. A.. United States Geological Survey; Estados Unidos
Materia
Pyroclastics
Ams
Patagonia
Volcanology
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:11336/79036
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/79036
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Towards the definition of AMS facies in the deposits of pyroclastic density currentsOrt, M. H.Newkirk, T.Vilas, Juan Francisco A.Vazquez, J. A.PyroclasticsAmsPatagoniaVolcanologyhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate-strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.Fil: Ort, M. H.. Northern Arizona University; Estados UnidosFil: Newkirk, T.. University of British Columbia; CanadáFil: Vilas, Juan Francisco A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Vazquez, J. A.. United States Geological Survey; Estados UnidosGeological Society of London2014-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/79036Ort, M. H.; Newkirk, T.; Vilas, Juan Francisco A.; Vazquez, J. A.; Towards the definition of AMS facies in the deposits of pyroclastic density currents; Geological Society of London; Geological Society of London Special Publication; 396; 1-2014; 205-2260305-8719CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1144/SP396.8info:eu-repo/semantics/altIdentifier/url/https://sp.lyellcollection.org/content/396/1/205.shortinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-10T13:04:20Zoai:ri.conicet.gov.ar:11336/79036instacron: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:34982025-09-10 13:04:20.335CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Towards the definition of AMS facies in the deposits of pyroclastic density currents
title Towards the definition of AMS facies in the deposits of pyroclastic density currents
spellingShingle Towards the definition of AMS facies in the deposits of pyroclastic density currents
Ort, M. H.
Pyroclastics
Ams
Patagonia
Volcanology
title_short Towards the definition of AMS facies in the deposits of pyroclastic density currents
title_full Towards the definition of AMS facies in the deposits of pyroclastic density currents
title_fullStr Towards the definition of AMS facies in the deposits of pyroclastic density currents
title_full_unstemmed Towards the definition of AMS facies in the deposits of pyroclastic density currents
title_sort Towards the definition of AMS facies in the deposits of pyroclastic density currents
dc.creator.none.fl_str_mv Ort, M. H.
Newkirk, T.
Vilas, Juan Francisco A.
Vazquez, J. A.
author Ort, M. H.
author_facet Ort, M. H.
Newkirk, T.
Vilas, Juan Francisco A.
Vazquez, J. A.
author_role author
author2 Newkirk, T.
Vilas, Juan Francisco A.
Vazquez, J. A.
author2_role author
author
author
dc.subject.none.fl_str_mv Pyroclastics
Ams
Patagonia
Volcanology
topic Pyroclastics
Ams
Patagonia
Volcanology
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate-strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.
Fil: Ort, M. H.. Northern Arizona University; Estados Unidos
Fil: Newkirk, T.. University of British Columbia; Canadá
Fil: Vilas, Juan Francisco A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina
Fil: Vazquez, J. A.. United States Geological Survey; Estados Unidos
description Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate-strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.
publishDate 2014
dc.date.none.fl_str_mv 2014-01
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/11336/79036
Ort, M. H.; Newkirk, T.; Vilas, Juan Francisco A.; Vazquez, J. A.; Towards the definition of AMS facies in the deposits of pyroclastic density currents; Geological Society of London; Geological Society of London Special Publication; 396; 1-2014; 205-226
0305-8719
CONICET Digital
CONICET
url http://hdl.handle.net/11336/79036
identifier_str_mv Ort, M. H.; Newkirk, T.; Vilas, Juan Francisco A.; Vazquez, J. A.; Towards the definition of AMS facies in the deposits of pyroclastic density currents; Geological Society of London; Geological Society of London Special Publication; 396; 1-2014; 205-226
0305-8719
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1144/SP396.8
info:eu-repo/semantics/altIdentifier/url/https://sp.lyellcollection.org/content/396/1/205.short
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 Geological Society of London
publisher.none.fl_str_mv Geological Society of London
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 12.993085

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