Topographical controls on small-volume pyroclastic flows

Emplacement of small-volume (<0·1 km3) pyroclastic flows is significantly influenced by topography. The Arico ignimbrite on Tenerife (Canary Islands) is a characteristic small-volume pyroclastic flow deposit emplaced on high relief topography. The pyroclastic flow flowed down pre-existing valleys...

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Detalles Bibliográficos
Autores: Martí Molist, Joan, Doronzo, Domenico Maria, Pedrazzi, Dario, Colombo Piñol, Ferrán
Tipo de recurso: artículo
Fecha de publicación:2019
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/184955
Acceso en línea:http://hdl.handle.net/10261/184955
Access Level:acceso abierto
Palabra clave:Arico ignimbrite
channel deposition
sediment gravity flow
small-volume pyroclastic flows
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spelling Topographical controls on small-volume pyroclastic flowsMartí Molist, JoanDoronzo, Domenico MariaPedrazzi, DarioColombo Piñol, FerránArico ignimbritechannel depositionsediment gravity flowsmall-volume pyroclastic flowsEmplacement of small-volume (<0·1 km3) pyroclastic flows is significantly influenced by topography. The Arico ignimbrite on Tenerife (Canary Islands) is a characteristic small-volume pyroclastic flow deposit emplaced on high relief topography. The pyroclastic flow flowed down pre-existing valleys on the southern slopes of the island. In proximal areas deep (up to 100 m) valleys acted as efficient conduits for the pyroclastic flow, which was mostly channelled; in this particular area the ignimbrite corresponds to a homogeneous, moderately welded deposit, consisting of flattened pumices in an abundant ashy matrix with a relatively low lithic fragment content. In intermediate zones significant changes occur in the steepness of the slope and, although still channelled, here the pyroclastic flow was influenced by hydraulic jumps. In this area, two different units can be clearly distinguished in the ignimbrite: the lower unit is composed of a lithic-rich ground-layer deposit that formed at the turbulent, highly concentrated head of the flow; the upper unit consists of a well welded pumice-rich deposit that occasionally reveals a basal layer formed by shearing with the lower part. This division into two units is maintained as far as distal areas near the present-day coastline, where the slope is very gentle or null and the ignimbrite is not channelled. The ground layer is not found in distal areas. The ignimbrite here only consists of the upper unit, which is occasionally repeated due to a surging process provoked by the lower flow speed, as the pyroclastic flow spread out of the channelled zone. A theoretical model on how topography controlled the deposition of the Arico ignimbrite is derived by interpreting the observed lithological and sedimentological variations in terms of changes in topography and bedrock morphology. This new model is of general applicability and will help to explain other deposits of similar characteristics. © 2019 The Authors. Sedimentology © 2019 International Association of SedimentologistsPeer reviewedJohn Wiley & SonsMartí Molist, Joan [0000-0003-3930-8603]Doronzo, Domenico Maria [0000-0002-6866-8870]Pedrazzi, Dario [0000-0002-6869-1325]Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]201920192019info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/184955reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1111/sed.12600Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1849552026-05-22T06:33:51Z
dc.title.none.fl_str_mv Topographical controls on small-volume pyroclastic flows
title Topographical controls on small-volume pyroclastic flows
spellingShingle Topographical controls on small-volume pyroclastic flows
Martí Molist, Joan
Arico ignimbrite
channel deposition
sediment gravity flow
small-volume pyroclastic flows
title_short Topographical controls on small-volume pyroclastic flows
title_full Topographical controls on small-volume pyroclastic flows
title_fullStr Topographical controls on small-volume pyroclastic flows
title_full_unstemmed Topographical controls on small-volume pyroclastic flows
title_sort Topographical controls on small-volume pyroclastic flows
dc.creator.none.fl_str_mv Martí Molist, Joan
Doronzo, Domenico Maria
Pedrazzi, Dario
Colombo Piñol, Ferrán
author Martí Molist, Joan
author_facet Martí Molist, Joan
Doronzo, Domenico Maria
Pedrazzi, Dario
Colombo Piñol, Ferrán
author_role author
author2 Doronzo, Domenico Maria
Pedrazzi, Dario
Colombo Piñol, Ferrán
author2_role author
author
author
dc.contributor.none.fl_str_mv Martí Molist, Joan [0000-0003-3930-8603]
Doronzo, Domenico Maria [0000-0002-6866-8870]
Pedrazzi, Dario [0000-0002-6869-1325]
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Arico ignimbrite
channel deposition
sediment gravity flow
small-volume pyroclastic flows
topic Arico ignimbrite
channel deposition
sediment gravity flow
small-volume pyroclastic flows
description Emplacement of small-volume (<0·1 km3) pyroclastic flows is significantly influenced by topography. The Arico ignimbrite on Tenerife (Canary Islands) is a characteristic small-volume pyroclastic flow deposit emplaced on high relief topography. The pyroclastic flow flowed down pre-existing valleys on the southern slopes of the island. In proximal areas deep (up to 100 m) valleys acted as efficient conduits for the pyroclastic flow, which was mostly channelled; in this particular area the ignimbrite corresponds to a homogeneous, moderately welded deposit, consisting of flattened pumices in an abundant ashy matrix with a relatively low lithic fragment content. In intermediate zones significant changes occur in the steepness of the slope and, although still channelled, here the pyroclastic flow was influenced by hydraulic jumps. In this area, two different units can be clearly distinguished in the ignimbrite: the lower unit is composed of a lithic-rich ground-layer deposit that formed at the turbulent, highly concentrated head of the flow; the upper unit consists of a well welded pumice-rich deposit that occasionally reveals a basal layer formed by shearing with the lower part. This division into two units is maintained as far as distal areas near the present-day coastline, where the slope is very gentle or null and the ignimbrite is not channelled. The ground layer is not found in distal areas. The ignimbrite here only consists of the upper unit, which is occasionally repeated due to a surging process provoked by the lower flow speed, as the pyroclastic flow spread out of the channelled zone. A theoretical model on how topography controlled the deposition of the Arico ignimbrite is derived by interpreting the observed lithological and sedimentological variations in terms of changes in topography and bedrock morphology. This new model is of general applicability and will help to explain other deposits of similar characteristics. © 2019 The Authors. Sedimentology © 2019 International Association of Sedimentologists
publishDate 2019
dc.date.none.fl_str_mv 2019
2019
2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/184955
url http://hdl.handle.net/10261/184955
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1111/sed.12600
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv John Wiley & Sons
publisher.none.fl_str_mv John Wiley & Sons
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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