Faulting-assisted lateral collapses and influence on shallow magma feeding system at Ollague volcano (Central Volcanic Zone, Chile-Bolivia Andes)

L. Vezzoli, A. Tibaldi, A. Renzulli, M. Menna, Stephanie Flude

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

The role played by the regional tectonics and relationships between volcanic structures and their shallow magmatic feeding system are of paramount importance in understanding multiple lateral collapse events and, thus, for hazard assessment in active volcanoes. Ollague (21 degrees 18'S, 68 degrees 11'W, Andean Central Volcanic Zone, Chile-Bolivia border) is an active, andesite-dacite, composite volcano developed on a regional NW-striking extensional fault system that bisects the volcanic edifice. Geological and stratigraphic studies on the summit part of the cone, together with new Ar-40/Ar-39 dating and petrographic and geochemical (major-trace elements) analyses, have allowed us to delineate the volcanic history of Ollague and recognize multiple deformation and lateral collapse events. The evolution of Ollague appears to be characterized by four stages of volcano building, separated by three main events of deformation of the cone. These deformation events developed progressively by downthrow of the SW sector of the volcano (similar to 800 ka), along the NW-striking normal fault propagating from the substrate, to a final catastrophic failure (similar to 300 ka) of the SW sector and debris avalanche emplacement. Both NW-trending regional tectonics and weakness of the edifice caused by the successive deformation and collapse events are responsible for both the geometric variations of the shallow magma feeding system and the coexistence of summit and parasitic dacitic vents. Central and lateral vents shifted in a SW-trending direction, i.e. perpendicular to the tectonic trend and along the axis of the collapse movement, and developed along a NW-trending alignment, i.e. parallel to the main tectonic trend and collapse scarps.
OriginalsprogEngelsk
TidsskriftJournal of Volcanology and Geothermal Research
Vol/bind171
Udgave nummer1-2
Sider (fra-til)137
Antal sider159
ISSN0377-0273
DOI
StatusUdgivet - 2008
Udgivet eksterntJa

Citer dette

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title = "Faulting-assisted lateral collapses and influence on shallow magma feeding system at Ollague volcano (Central Volcanic Zone, Chile-Bolivia Andes)",
abstract = "The role played by the regional tectonics and relationships between volcanic structures and their shallow magmatic feeding system are of paramount importance in understanding multiple lateral collapse events and, thus, for hazard assessment in active volcanoes. Ollague (21 degrees 18'S, 68 degrees 11'W, Andean Central Volcanic Zone, Chile-Bolivia border) is an active, andesite-dacite, composite volcano developed on a regional NW-striking extensional fault system that bisects the volcanic edifice. Geological and stratigraphic studies on the summit part of the cone, together with new Ar-40/Ar-39 dating and petrographic and geochemical (major-trace elements) analyses, have allowed us to delineate the volcanic history of Ollague and recognize multiple deformation and lateral collapse events. The evolution of Ollague appears to be characterized by four stages of volcano building, separated by three main events of deformation of the cone. These deformation events developed progressively by downthrow of the SW sector of the volcano (similar to 800 ka), along the NW-striking normal fault propagating from the substrate, to a final catastrophic failure (similar to 300 ka) of the SW sector and debris avalanche emplacement. Both NW-trending regional tectonics and weakness of the edifice caused by the successive deformation and collapse events are responsible for both the geometric variations of the shallow magma feeding system and the coexistence of summit and parasitic dacitic vents. Central and lateral vents shifted in a SW-trending direction, i.e. perpendicular to the tectonic trend and along the axis of the collapse movement, and developed along a NW-trending alignment, i.e. parallel to the main tectonic trend and collapse scarps.",
author = "L. Vezzoli and A. Tibaldi and A. Renzulli and M. Menna and Stephanie Flude",
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journal = "Journal of Volcanology and Geothermal Research",
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Faulting-assisted lateral collapses and influence on shallow magma feeding system at Ollague volcano (Central Volcanic Zone, Chile-Bolivia Andes). / Vezzoli, L.; Tibaldi, A.; Renzulli, A.; Menna, M.; Flude, Stephanie.

I: Journal of Volcanology and Geothermal Research, Bind 171, Nr. 1-2, 2008, s. 137.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Faulting-assisted lateral collapses and influence on shallow magma feeding system at Ollague volcano (Central Volcanic Zone, Chile-Bolivia Andes)

AU - Vezzoli, L.

AU - Tibaldi, A.

AU - Renzulli, A.

AU - Menna, M.

AU - Flude, Stephanie

PY - 2008

Y1 - 2008

N2 - The role played by the regional tectonics and relationships between volcanic structures and their shallow magmatic feeding system are of paramount importance in understanding multiple lateral collapse events and, thus, for hazard assessment in active volcanoes. Ollague (21 degrees 18'S, 68 degrees 11'W, Andean Central Volcanic Zone, Chile-Bolivia border) is an active, andesite-dacite, composite volcano developed on a regional NW-striking extensional fault system that bisects the volcanic edifice. Geological and stratigraphic studies on the summit part of the cone, together with new Ar-40/Ar-39 dating and petrographic and geochemical (major-trace elements) analyses, have allowed us to delineate the volcanic history of Ollague and recognize multiple deformation and lateral collapse events. The evolution of Ollague appears to be characterized by four stages of volcano building, separated by three main events of deformation of the cone. These deformation events developed progressively by downthrow of the SW sector of the volcano (similar to 800 ka), along the NW-striking normal fault propagating from the substrate, to a final catastrophic failure (similar to 300 ka) of the SW sector and debris avalanche emplacement. Both NW-trending regional tectonics and weakness of the edifice caused by the successive deformation and collapse events are responsible for both the geometric variations of the shallow magma feeding system and the coexistence of summit and parasitic dacitic vents. Central and lateral vents shifted in a SW-trending direction, i.e. perpendicular to the tectonic trend and along the axis of the collapse movement, and developed along a NW-trending alignment, i.e. parallel to the main tectonic trend and collapse scarps.

AB - The role played by the regional tectonics and relationships between volcanic structures and their shallow magmatic feeding system are of paramount importance in understanding multiple lateral collapse events and, thus, for hazard assessment in active volcanoes. Ollague (21 degrees 18'S, 68 degrees 11'W, Andean Central Volcanic Zone, Chile-Bolivia border) is an active, andesite-dacite, composite volcano developed on a regional NW-striking extensional fault system that bisects the volcanic edifice. Geological and stratigraphic studies on the summit part of the cone, together with new Ar-40/Ar-39 dating and petrographic and geochemical (major-trace elements) analyses, have allowed us to delineate the volcanic history of Ollague and recognize multiple deformation and lateral collapse events. The evolution of Ollague appears to be characterized by four stages of volcano building, separated by three main events of deformation of the cone. These deformation events developed progressively by downthrow of the SW sector of the volcano (similar to 800 ka), along the NW-striking normal fault propagating from the substrate, to a final catastrophic failure (similar to 300 ka) of the SW sector and debris avalanche emplacement. Both NW-trending regional tectonics and weakness of the edifice caused by the successive deformation and collapse events are responsible for both the geometric variations of the shallow magma feeding system and the coexistence of summit and parasitic dacitic vents. Central and lateral vents shifted in a SW-trending direction, i.e. perpendicular to the tectonic trend and along the axis of the collapse movement, and developed along a NW-trending alignment, i.e. parallel to the main tectonic trend and collapse scarps.

U2 - 10.1016/j.jvolgeores.2007.11.015

DO - 10.1016/j.jvolgeores.2007.11.015

M3 - Journal article

VL - 171

SP - 137

JO - Journal of Volcanology and Geothermal Research

JF - Journal of Volcanology and Geothermal Research

SN - 0377-0273

IS - 1-2

ER -