Explosive origin of silicic lava: Textural and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mi>δ</mml:mi><mml:mi mathvariant="normal">D</mml:mi></mml:math>–H 2 O evidence for pyroclastic degassing during rhyolite effusion

Castro, Jonathan M.; Bindeman, Ilya N.; Tuffen, Hugh; Schipper, C. Ian

doi:10.1016/j.epsl.2014.08.012

Cited by 116 publications

(197 citation statements)

References 49 publications

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“…Tuffisite veins show varying degrees of sintering or healing of the pyroclastic fragments (Stasiuk et al, 1996;Tuffen et al, 2003) and have also been shown to preserve massive to flow-banded or even bedded structures that form during turbulent, fluidized flow of the particulate material in the fractures (Tuffen et al, 2003). Typically, evidence for deformation of the surrounding host magma is minimal since tuffisites likely form during short-lived explosions that rip apart the hot magma (Kolzenburg et al, 2012;Castro et al, 2014).…”

Section: Magma Fragmentation and Tuffisite Formationmentioning

confidence: 99%

“…The infiltration of fracture networks by hot gas and ash mixtures (Cloos, 1941;Tuffen et al, 2003;Castro et al, 2012Castro et al, , 2014Kolzenburg et al, 2012;Schipper et al, 2013) occurs during explosive volcanism as a result of subsurface fragmentation events. Tuffisites can both create or use pre-existing fractures (Stasiuk et al, 1996;Kolzenburg et al, 2012), and some tuffisites may represent the origin point of fragmentation events in the lava.…”

Section: Magma Fragmentation and Tuffisite Formationmentioning

confidence: 99%

“…Recent developments have seen a quantification of the influence of temperature fluctuations on the volatile budget of magma; whereby magma may be forced to rapidly vesiculate (degas) and fragment as a result of small temperature increments . Hence, it may be viewed that fragmentation increases degassing efficiency in silicic systems (Watts et al, 2002;Castro et al, 2014;Lavallée et al, 2015), and furthermore, relic fragmentation structures have been proposed as pathways that also allow passive bleeding of gases (Gonnermann and Manga, 2003;Castro et al, 2012;Burgisser and Degruyter, 2015) that may lower the explosive potential of an ongoing eruption. In addition, fragmentation has been linked to characteristic seismicity which occurs at shallow depth during magma migration (Neuberg, 2000;Green and Neuberg, 2006;Neuberg et al, 2006;SahetapyEngel et al, 2008;Palo et al, 2009;Varley et al, 2010;Arámbula-Mendoza et al, 2011;Thomas and Neuberg, 2012;Chouet and Matoza, 2013;Lamb et al, 2014;Webb et al, 2014;Arciniega−Ceballos et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Blowing Off Steam: Tuffisite Formation As a Regulator for Lava Dome Eruptions

et al. 2016

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Tuffisites are veins of variably sintered, pyroclastic particles that form in conduits and lava domes as a result of localized fragmentation events during gas-and-ash explosions. Those observed in-situ on the active 2012 lava dome of Volcán de Colima range from voids with intra-clasts showing little movement and interpreted to be failure-nuclei, to sub-parallel lenses of sintered granular aggregate interpreted as fragmentation horizons, through to infilled fractures with evidence of viscous remobilization. All tuffisites show evidence of sintering. Further examination of the complex fracture-and-channel patterns reveals viscous backfill by surrounding magma, suggesting that lava fragmentation was followed by stress relaxation and continued viscous deformation as the tuffisites formed. The natural tuffisites are more permeable than the host andesite, and have a wide range of porosity and permeability compared to a narrower window for the host rock, and gaging from their significant distribution across the dome, we posit that the tuffisite veins may act as important outgassing pathways. To investigate tuffisite formation we crushed and sieved andesite from the lava dome and sintered it at magmatic temperatures for different times. We then assessed the healing and sealing ability by measuring porosity and permeability, showing that sintering reduces both over time. During sintering the porosity-permeability reduction occurs due to the formation of viscous necks between adjacent grains, a process described by the neck-formation model of Frenkel (1945). This process leads the granular starting material to a porosity-permeability regime anticipated for effusive lavas, and which describes the natural host lava as well as the most impervious of natural tuffisites. This suggests that tuffisite formation at Volcán de Colima constructed a permeable network that enabled gas to bleed passively from the magma. We postulate that this progressively reduced the lava dome's ability to seal and build pressure that drives explosions. Indeed, the time interval between explosions during 2007-2011 gradually increased before the onset of a period of quiescence starting in June 2011. We suggest that the permeability evolution during tuffisite formation has important consequences for modeling of gas-and-ash explosions, common at dome-forming volcanoes.

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Section: Magma Fragmentation and Tuffisite Formationmentioning

confidence: 99%

Section: Magma Fragmentation and Tuffisite Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Blowing Off Steam: Tuffisite Formation As a Regulator for Lava Dome Eruptions

et al. 2016

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“…This is due in part to a lack of observations of active flows. Prior to 2008, no rhyolite-forming eruption had been witnessed and documented Schipper et al 2013;Castro et al 2014). As a result of this, our understanding of the mechanics of basaltic lava flow emplacement is confirmed by real-time observations, while our knowledge of rhyolitic lava Editorial responsibility: K.V.…”

Section: Introductionmentioning

confidence: 99%

Emplacement of the Rocche Rosse rhyolite lava flow (Lipari, Aeolian Islands)

2018

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The Rocche Rosse lava flow marks the most recent rhyolitic extrusion on Lipari island (Italy), and preserves evidence for a multi-stage emplacement history. Due to the viscous nature of the advancing lava (10 8 to 10 10 Pa s), indicators of complex emplacement processes are preserved in the final flow. This study focuses on structural mapping of the flow to highlight the interplay of cooling, crust formation and underlying slope in the development of rhyolitic lavas. The flow is made up of two prominent lobes, small (< 0.2 m) to large (> 0.2 m) scale folding and a channelled geometry. Foliations dip at 2-4°over the flatter topography close to the vent, and up to 30-50°over steeper mid-flow topography. Brittle faults, tension gashes and conjugate fractures are also evident across flow. Heterogeneous deformation is evident through increasing fold asymmetry from the vent due to downflow cooling and stagnation. A steeper underlying topography mid-flow led to development of a channelled morphology, and compression at topographic breaks resulted in fold superimposition in the channel. We propose an emplacement history that involved the evolution through five stages, each associated with the following flow regimes: (1) initial extrusion, crustal development and small scale folding; (2) extensional strain, stretching lineations and channel development over steeper topography; (3) compression at topographic break, autobrecciation, lobe development and medium scale folding; (4) progressive deformation with stagnation, large-scale folding and refolding; and (5) brittle deformation following flow termination. The complex array of structural elements observed within the Rocche Rosse lava flow facilitates comparisons to be made with actively deforming rhyolitic lava flows at the Chilean volcanoes of Chaitén and Cordón Caulle, offering a fluid dynamic and structural framework within which to evaluate our data.

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“…Heap et al, 2014;Kolzenburg and Russell, 2014;Wadsworth et al, 2014). Manly (1996) suggested that vitric fragments such as shards and pumices begin to distort and stretch up to the volcaniclastic flow becomes completely layered/banded in a viscous manner (Andrews and Branney, 2011;Castro et al, 2014). Since the discovery of welded ignimbrites during 1960s (Ross and Smith, 1961;Schmincke and Swanson, 1967;Smith, 1960;Walker and Swanson, 1968) there has been lot of controversy related to recognition, origin, transport and emplacement mechanisms of intensely welded to rheomorphic ignimbrites.…”

Section: Ignimbritic Textures: a Reviewmentioning

confidence: 99%

Paleoproterozoic felsic volcanism of the Tapajós Mineral Province, Southern Amazon Craton, Brazil

Roverato

Giordano

Echeverri-Misas

et al. 2016

Journal of Volcanology and Geothermal Research

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Amazonian rocks record one amongst the most complete and best-preserved Paleoproterozoic magmatic episodes on Earth. The present contribution documents the extremely well preserved paleoproterozoic architecture of a series of felsic rocks found in the Tapajós Mineral Province (TMP), located in the western part of Pará state, southern Amazon Craton, north of Brazil. These rocks are the first to be investigated to comprehend, based on their textural evidences, their emplacement mechanisms. Textural characterization allowed to identify three main facies with, as following reported, 1) chaotic ("Breccia") group, 2) eutaxitic ("Eutax") group and 3) parataxitic ("Paratax") group vitrophyric texture. Given the superb preservation of our samples, the investigated rocks are grouped, according to their grade of welding, into a wide variety of lithofacies from very low-grade to high-grade and rheomorphic ignimbrites. In the "paratax group" strong similarities with banding in lava flows are observed. Based on the presented data we discuss the effusive or explosive origin of the observed flow mechanisms.

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Explosive origin of silicic lava: Textural andδD–H 2 O evidence for pyroclastic degassing during rhyolite effusion

Cited by 116 publications

References 49 publications

Blowing Off Steam: Tuffisite Formation As a Regulator for Lava Dome Eruptions

Blowing Off Steam: Tuffisite Formation As a Regulator for Lava Dome Eruptions

Emplacement of the Rocche Rosse rhyolite lava flow (Lipari, Aeolian Islands)

Paleoproterozoic felsic volcanism of the Tapajós Mineral Province, Southern Amazon Craton, Brazil

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