Welding: insights from high-temperature analogue experiments

Quane, Steven L.; Russell, James K.

doi:10.1016/j.jvolgeores.2004.10.014

Cited by 65 publications

(54 citation statements)

References 29 publications

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“…The holocrystalline nature of these tuffisites precludes recovery and lithification by the processes that govern welding of other, glassy, volcanic rocks (i.e., healing via structural relaxation of melt fragments; e.g., Quane and Russell (2005)). Other potential processes include, for example, hot pressing (Olgaard and Fitz Gerald, 1993), solid-state diffusion (Venkatachari and Raj, 1986) and precipitation of minerals from fluids (Taran et al, 2001) as these fragmented materials are subject to significant pressures, elevated temperatures and circulating fluids while residing in the volcanic edifice.…”

Section: Discussionmentioning

confidence: 99%

Strength and permeability recovery of tuffisite-bearing andesite

Kolzenburg

Heap

Lavallée³

et al. 2012

Solid Earth

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Abstract. Tuffisites, the products of subsurface fragmentation, transport and deposition, are common in explosive volcanic environments. Their study provides direct insight to the mechanical processes operating within volcanic conduits. Here we document the influence of the presence of coherent tuffisite veins on the physical properties of andesitic rocks. We find that (1) compressive strength is unaffected by the presence and/or orientation of tuffisites, (2) permeability doubles when tuffisites are oriented favorably (at 45 • to the fluid flow direction), and (3) ultrasonic wave velocities show a continuous increase with depth, independent of vein presence and orientation. Although the influence of tuffisites on andesitic rock properties determined here is modest, we emphasize that the material tested represents the post-eruptive state of tuffisite. Thus, these results likely delineate the upper and lower boundaries of strength vs. permeability and porosity, respectively. Our evidence suggests that, via compaction and lithification, tuffisites may restore the strength of the volcanic host-rocks to that of their pre-tuffisite values.

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Section: Discussionmentioning

confidence: 99%

Strength and permeability recovery of tuffisite-bearing andesite

Kolzenburg

Heap

Lavallée³

et al. 2012

Solid Earth

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“…Glass hydration and associated rheological changes thus 563 increase the compaction rate and allow compaction at lower temperature than for dry 564 materials. Furthermore, these experiments provide new constraints on the rheology of soda-565 lime glass, which is used for analogue modeling of volcanic processes (Quane et al, 2004; 566 Quane & Russell, 2005). 567 568…”

Section: Comparison With Power-law Creep 466mentioning

confidence: 99%

Influence of time, temperature, confining pressure and fluid content on the experimental compaction of spherical grains

Rossi¹,

Vidal²,

Wunder³

et al. 2007

Tectonophysics

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25Theoretical models of compaction processes, such as for example intergranular 26 pressure-solution (IPS), focus on deformation occurring at the contacts between spherical 27 grains that constitute an aggregate. In order to investigate the applicability of such models, 28and to quantify the deformation of particles within an aggregate, isostatic experiments were 29 performed in cold-sealed vessels on glass sphere aggregates at 200 MPa confining pressure 30 and 350°C with varying amounts of fluid. Several runs were performed in order to investigate 31 the effects of time, fluid content, pressure and temperature, by varying one of these 32 parameters and holding the others fixed. In order to compare the aggregates with natural 33 materials, similar experiments were also performed using quartz sand instead of glass spheres. 34Experiments with quartz show evidence of IPS, but the strain could not be quantified. behavior that is typical of glass deformation, following an exponential law. These 41 experiments can also be made to fit a power law for creep, with a stress exponent of 42 n = 10.5 ± 2.2 in both dry and wet experiments. However, the pre-factor of the power law 43 creep increases 5 times with the addition of water, showing the strong effect of water on the 44 deformation rate. These simple and low-cost experiments provide new insights on the 45 rheology of plastically deformed aggregates, which are found in many geological 46 environments, such as partially molten-rocks, pyroclastic deposits or fault gouges during the 47 inter-seismic period. 48 49

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“…Variações no conteúdo de água podem reduzir a temperatura mínima de soldagem para 600 o C em sistemas silicosos metaluminosos (Quane & Russell 2005). De acordo com Dingwell & Webb (1990), esta temperatura representa o limite cinético entre um "líquido" (sistema viscoso) e um sólido (elástico) em resposta ao esforço mecâ-nico aplicado.…”

Section: Discussionunclassified

Reoignimbritos e ignimbritos de alto grau do vulcanismo Acampamento Velho, RS: origem e temperatura de formação

Sommer

Lima

Pierosan

et al. 2011

RBG

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Resumo A Formação Acampamento Velho é constituída por depósitos vulcânicos neoproterozoicos dominantemente ácidos, emplaçados em condições subaéreas sobre o Escudo Sul-Rio-Grandense. Registros deste vulcanismo são encontrados nos platôs da Ramada e Taquarembó localizados no sudoeste do Estado do Rio Grande do Sul. Este magmatismo varia de metaluminoso a peralcalino e apresenta afi nidade alcalina sódica. Nos depósitos de fl uxo piroclásticos dominam fragmentos juvenis, como púmices, shards e fragmentos vítreos maciços. Estes apresentam um típico elevado grau de soldagem com ignimbritos, com alto grau nas porções de base e intermediárias, e reoignimbritos no topo. 11 a 6,55 x 10 11 Pa s para os ignimbritos. Os conteúdos de Zr crescem em direção ao topo da sequência piroclástica indicando aumento da peralcalinidade, que determinou a redução da viscosidade dos clastos nas porções superiores dos fl uxos. Um modelo agradacional progressivo permite explicar as variações verticais no tamanho e tipos de clastos, e na geoquímica do depósito. Este modelo assume a aglutinação de partículas juvenis quentes durante o deslocamento do fl uxo, o que espessa progressivamente o depósito. Portanto, a elevada soldagem e o reomorfi smo são sin-deposicionais. Os fl uxos piroclásticos de alta temperatura dos platôs da Ramada e Taquarembó foram gerados a partir de baixas colunas de erupção e podem ser interpretados como depósitos ignimbríticos extracaldeira.Palavras-chave: vulcanismo, depósitos ignimbríticos, soldagem, rochas ácidas. Abstract Reoignimbrites and high-grade ignimbrites of Acampamento Velho volcanism, RS: origin and formation temperature.The Acampamento Velho Formation is constituted by neoproterozoic volcanic deposits of dominantly acid composition, which were emplaced under subaerial conditions on Sul-RioGrandense Shield. The volcanism registration have been found at Ramada and Taquarembó plateaus localized at southwest of Rio Grande do Sul State. This magmatism varies from metaluminous to peralkaline and shows alkaline sodic affi nity. At the pyroclastic fl ow deposits dominate juvenile fragments such as pumices, shards and massive vitreous fragments, which show a typical high welding degree with ignimbrites, being high degree at the base and intermediate portions, and reoignimbrites at the top. The pre-eruptive temperature calculations obtained at the saturation of zircon show values between 870-978 o C for Taquarembó Plateau and 850-946 o C for Ramada Plateau. The calculated viscosity values vary from 4.77 x 10 7 to 1.39 x 10 8 Pa s for the reoignimbrites, and 1.72 x10 11 to 6.55 x 10 11 Pa s for the ignimbrites. Zr contents increase to the pyroclastic sequence top, indicating increasing of peralkalinity, which determined the viscosity reduction of clasts at the upper portions of the fl ows. The progressive aggradacional model allows explaining the vertical variations at the clast size and type, and at the geochemistry of the deposit. This model assumes the agglutination of hot juvenile particles during the fl ow mo...

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Welding: insights from high-temperature analogue experiments

Cited by 65 publications

References 29 publications

Strength and permeability recovery of tuffisite-bearing andesite

Strength and permeability recovery of tuffisite-bearing andesite

Influence of time, temperature, confining pressure and fluid content on the experimental compaction of spherical grains

Reoignimbritos e ignimbritos de alto grau do vulcanismo Acampamento Velho, RS: origem e temperatura de formação

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