Field observations and numerical models of a Pleistocene-Holocene feeder dyke swarm associated with a fissure complex to the east of the Tatara-San Pedro-Pellado complex, Southern Volcanic Zone, Chile

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dc.article.number107033
dc.catalogadorgjm
dc.contributor.authorRuz Ginouves, Javiera Andrea
dc.contributor.authorBrowning, John
dc.contributor.authorCembrano, José
dc.contributor.authorIturrieta, Pablo
dc.contributor.authorGerbault, Muriel
dc.contributor.authorSielfeld, Gerd
dc.date.accessioned2024-05-30T16:23:16Z
dc.date.available2024-05-30T16:23:16Z
dc.date.issued2020
dc.description.abstractMagma is transported through the lithosphere as dykes which, during periods of unrest, may feed eruptions at the surface. The propagation path of dykes is influenced by the crustal stress field and can be disturbed by crustal heterogeneities such as contrasting rock units or faults. Moreover, as dykes propagate, they themselves influence the surrounding stress field through processes of stress transfer, crustal deformation and seismic failure. The result is the formation of arrested dykes, as well as contrasting strike and dip angles and dyke segmentation. Here, we study the mechanisms of dyke injection and the role played in modifying the stress field and potential propagation paths of later dyke injections. To do this we combine field data from an eroded and well-exposed shallow feeder dyke swarm with a suite of two-dimensional FEM numerical models. We mapped 35 dyke segments over a ~1 km long dyke swarm exposed ~5 km to the East of Pellado Volcano, in the Tatara-San Pedro-Pellado (TSPP) volcanic complex, Southern Volcanic Zone of the Andes. Detailed mapping of the swarm elucidates two preferential strike orientations, one ~N80°E and the other ~N60°E. Our numerical models simulate both the TSPP volcanic complex and the studied dyke swarm as zones of either magmatic excess pressure or as a rigid inclusion. The crustal segment hosting the volcanic complex and dykes is modelled using an elastic domain subjected to regional compression in select model cases. Model outputs provide the stress and strain fields resulting from the different geometries and applied boundary loads. The model results indicate that individual dyke injections can locally rotate the principal stresses such as to influence the range of orientations over which later dykes will form. The orientation of σ1 at the dyke tip ranges over 60° (±30° either side of the dyke tip) indicating that the strike orientation of later dykes will fall within this range. The effect of adding a bulk regional compression is to locally increase the magnitude of favorably oriented tensile stresses in the bedrock but to reduce the range of σ1 orientations to 40° (±20°). This implies that under a far-field transpressive stress regime, as is common in Andean settings, regional dyke swarms will tend to maintain their strike orientation parallel to the regional bulk stress. These results should be accounted for when studying periods of volcanic unrest in order to discern the location and orientation of potential fissure eruptions in active volcanic areas such as the Southern Volcanic Zone of the Andes.
dc.format.extent19 páginas
dc.fuente.origenORCID
dc.identifier.doi10.1016/j.jvolgeores.2020.107033
dc.identifier.urihttp://dx.doi.org/10.1016/j.jvolgeores.2020.107033
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/86043
dc.information.autorucEscuela de Ingeniería; Browning, John; 0000-0001-8022-6234; 1081089
dc.language.isoen
dc.nota.accesocontenido parcial
dc.revistaJournal of Volcanology and Geothermal Research
dc.rightsacceso restringido
dc.subjectDyke propagation paths
dc.subjectSouthern Volcanic Zone
dc.subjectNumerical modelling
dc.subjectFissure eruptions
dc.subjectArc volcanism
dc.subjectTranspressional convergence
dc.subject.ddc620
dc.subject.deweyIngenieríaes_ES
dc.titleField observations and numerical models of a Pleistocene-Holocene feeder dyke swarm associated with a fissure complex to the east of the Tatara-San Pedro-Pellado complex, Southern Volcanic Zone, Chile
dc.typeartículo
dc.volumen404
sipa.codpersvinculados1081089
sipa.trazabilidadORCID;2024-05-27
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