The magma plumbing system for the 1971 Teneguía eruption on La Palma, Canary Islands

Barker, Abigail K.; Troll, Valentin R.; Carracedo, Juan Carlos; Nicholls, Peter A.

doi:10.1007/s00410-015-1207-7

Cited by 57 publications

(79 citation statements)

References 48 publications

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“…Sub‐Moho to Moho‐level crystallization has frequently been identified through clinopyroxene thermobarometry, e.g., in several oceanic mafic volcanoes (e.g., Cape Verde [ Barker et al ., ]; Gran Canaria [ Aulinas et al ., ]; Tenerife [ Longpré et al ., ]; and La Palma [ Galipp et al ., ]). A likely reason for the Moho‐region to be a site of magma storage is the density contrast between mantle and crustal rocks at this boundary [ Hansteen et al ., ; Barker et al ., ]. Beneath Katla, the Moho is estimated at ∼24 km depth [ Darbyshire et al ., ; Allen et al ., ; Foulger et al ., ], and our data record extensive crystallization within ±10 km of this level.…”

Section: Resultsmentioning

confidence: 99%

Persistent multitiered magma plumbing beneath Katla volcano, Iceland

Budd

Troll

Dahrén

et al. 2016

Geochem Geophys Geosyst

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Recent seismic unrest and a persistent Holocene eruption record at Katla volcano, Iceland indicate that a near‐future eruption is possible. Previous petrological investigations suggest that Katla is supplied by a simple plumbing system that delivers magma directly from depth, while seismic and geodetic data also point toward the existence of upper‐crustal magma storage. To characterize Katla's recent plumbing system, we established mineral‐melt equilibrium crystallization pressures from four age‐constrained Katla tephras spanning from 8 kyr BP to 1918. The results point to persistent shallow‐ (≤8 km depth) as well as deep‐crustal (ca. 10 – 25 km depth) magma storage beneath Katla throughout the last 8 kyr. The presence of multiple magma storage regions implies that mafic magma from the deeper reservoir system may become gas‐rich during ascent and storage in the shallow crust and erupt explosively. Alternatively, it might intersect evolved magma pockets in the shallow‐level storage region, and so increase the potential for explosive mixed‐magma ash eruptions.

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Section: Resultsmentioning

confidence: 99%

Persistent multitiered magma plumbing beneath Katla volcano, Iceland

Budd

Troll

Dahrén

et al. 2016

Geochem Geophys Geosyst

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“…Uncertainties are as follows: SiO 2 , Al 2 O 3 , MgO and CaO ≤ 1.5% s.d., FeO ≤ 2.2% s.d., Na 2 O in plagioclase and clinopyroxene ≤ 4.5% s.d., and minor elements ≤ 10% s.d. [see Barker et al ., , for full details]. The resulting mineral data comprise 605 point analyses from 387 individual clinopyroxene crystals, 176 point analyses from 91 plagioclase crystals, and five averaged grid analyses of groundmass (see supporting information Table S2 for full mineral and groundmass compositional data set).…”

Section: Methodsmentioning

confidence: 99%

Magma plumbing for the 2014–2015 Holuhraun eruption, Iceland

Geiger

Mattsson

Deegan

et al. 2016

Geochem Geophys Geosyst

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The 2014–2015 Holuhraun eruption on Iceland was located within the Askja fissure swarm but was accompanied by caldera subsidence in the Bárðarbunga central volcano 45 km to the southwest. Geophysical monitoring of the eruption identified a seismic swarm that migrated from Bárðarbunga to the Holuhraun eruption site over the course of two weeks. In order to better understand this lateral connection between Bárðarbunga and Holuhraun, we present mineral textures and compositions, mineral‐melt‐equilibrium calculations, whole rock and trace element data, and oxygen isotope ratios for selected Holuhraun samples. The Holuhraun lavas are compositionally similar to recorded historical eruptions from the Bárðarbunga volcanic system but are distinct from the historical eruption products of the nearby Askja system. Thermobarometry calculations indicate a polybaric magma plumbing system for the Holuhraun eruption, wherein clinopyroxene and plagioclase crystallized at average depths of ∼17 km and ∼5 km, respectively. Crystal resorption textures and oxygen isotope variations imply that this multilevel plumbing system facilitated magma mixing and assimilation of low‐δ18O Icelandic crust prior to eruption. In conjunction with the existing geophysical evidence for lateral migration, our results support a model of initial vertical magma ascent within the Bárðarbunga plumbing system followed by lateral transport of aggregated magma batches within the upper crust to the Holuhraun eruption site.

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“…Several crystals showed weak zonation in backscattered electron (BSE) images and for each crystal an average composition was calculated from all analyzed spots. A detailed description of the EPMA procedure and the analytical uncertainties is presented in Barker et al (2015). From the obtained weight percentages, the number of atoms per formula unit in each crystal was calculated on the basis of a four cation-normalization.…”

Section: Electron Probe Microanalysismentioning

confidence: 99%

“…1a and 4). Using compositional data for amphibole pheno-and xenocrysts in basanite and phonolite lavas from La Palma and the kaersutite cumulate xenolith from this study (sample LP1971-B) (Klügel et al 2000;Barker et al 2015) reveals magmatic water contents between 3.37 ± 0.78 and 4.48 ± 0.78 wt% (Appendix 1 A1) with an average of 3.76 ± 0.78 wt% H 2 O. These values overlap with the range obtained through pressure-annealed clinopyroxene from the Western Canaries.…”

Section: Reconstruction Of Initial Water Contents In Clinopyroxenesmentioning

confidence: 99%

Experimental hydration of natural volcanic clinopyroxene phenocrysts under hydrothermal pressures (0.5–3 kbar)

Weis

Stalder

Skogby

2016

American Mineralogist

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Water is a key parameter in mantle rheology, magma genesis, magma evolution, and resulting eruption styles, because it controls the density and the viscosity, as well as the melting and crystallization behavior of a melt. The water content in nominally anhydrous minerals (NAMs) such as clinopyroxene recently has been used as a proxy for magmatic water contents. NAMs, however, may dehydrate during magma degassing and eruption. We performed rehydration experiments on potentially degassed clinopyroxene phenocrysts from various volcanic settings. The experiments were conducted in hydrogen gas at 1 atm or hydrothermal pressures ranging from 0.5 to 3 kbar to test the incorporation of water into natural clinopyroxene under water fugacities similar to those in a volcanic system. Our results show a dependence of the water content in the clinopyroxene crystals with pressure as the phenocrysts begin to dehydrate upon lower water fugacities in the experiments. Water loss or gain in a crystal occurs according to the relatively fast redox-reaction OH -+ Fe 2+ ↔ O 2-+ Fe 3+ + ½ H 2 , which was confirmed by Mössbauer spectroscopy. The kinetics of this redox-process are independent of pressure and thus water fugacity. Water contents in rehydrated clinopyroxene crystals can be related to magmatic water contents at various levels in a volcanic system. Our results thus show that the water content in erupted clinopyroxene phenocrysts cannot be taken for granted to be representative of magmatic water contents prior to magma degassing. The conducted experiments indicate the simultaneous dehydration of clinopyroxene along with magma ascent and degassing. Rehydration experiments under hydrothermal pressures, however, may be able to reconstruct clinopyroxene water contents at crystallization prior to dehydration.

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The magma plumbing system for the 1971 Teneguía eruption on La Palma, Canary Islands

Cited by 57 publications

References 48 publications

Persistent multitiered magma plumbing beneath Katla volcano, Iceland

Persistent multitiered magma plumbing beneath Katla volcano, Iceland

Magma plumbing for the 2014–2015 Holuhraun eruption, Iceland

Experimental hydration of natural volcanic clinopyroxene phenocrysts under hydrothermal pressures (0.5–3 kbar)

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