Thermal effects of the intrusion of basaltic magma into a more silicic magma chamber and implications for eruption triggering

Snyder, Don

doi:10.1016/s0012-821x(99)00301-5

Cited by 114 publications

(74 citation statements)

References 58 publications

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“…Measurements on quenched enclaves have shown that they preserve a density difference of about À 600 kg m À 3 with their host 17 . Using typical enclaves sizes (cm to dm (refs 18,21)) their ascent rates predicted by the Stokes law are in the range 10 À 5 -10 À 7 m s À 1 (for a viscosity of 10 5 Pa s, typical of felsic arc magmas 27 ), which correspond to shear rates of 10 À 5 -10 À 8 s À 1 , if the rise occurs over a 1-10-m thick layer (the approximate thickness of a thermal boundary layer 55 ). Such shear rates will not decrease viscosities, and any viscous blob rising through a static felsic layer will likely keep its coherency.…”

Section: Resultsmentioning

confidence: 99%

“…Such shear rates will not decrease viscosities, and any viscous blob rising through a static felsic layer will likely keep its coherency. However, these ascent rates may be superseded by the vigour of convection in the felsic layer, which is fuelled by the thermal input of the underlying mafic intrusion 55 . Current estimates of convective velocities of felsic reservoirs vary widely 12,25 , from 10 À 8 m s À 1 up to 10 À 2 m s À 1 , and natural systems quite certainly display a range of convection rates, depending in particular on magma crystallinity.…”

Section: Resultsmentioning

confidence: 99%

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On the conditions of magma mixing and its bearing on andesite production in the crust

et al. 2014

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Mixing between magmas is thought to affect a variety of processes, from the growth of continental crust to the triggering of volcanic eruptions, but its thermophysical viability remains unclear. Here, by using high-pressure mixing experiments and thermal calculations, we show that hybridization during single-intrusive events requires injection of high proportions of the replenishing magma during short periods, producing magmas with 55-58 wt% SiO 2 when the mafic end-member is basaltic. High strain rates and gas-rich conditions may produce more felsic hybrids. The incremental growth of crustal reservoirs limits the production of hybrids to the waning stage of pluton assembly and to small portions of it. Large-scale mixing appears to be more efficient at lower crustal conditions, but requires higher proportions of mafic melt, producing more mafic hybrids than in shallow reservoirs. Altogether, our results show that hybrid arc magmas correspond to periods of enhanced magma production at depth.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

On the conditions of magma mixing and its bearing on andesite production in the crust

et al. 2014

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“…Physical and thermodynamic properties of silicate melts are key factors governing petrological and volcanic processes such as melt generation, transport, emplacement, crystallization, degassing and eruptive style (e.g., Lange and Carmichael, 1990;Dingwell et al, 1996;Ochs and Lange, 1999;Papale, 1999;Snyder, 2000;Spera, 2000;Dingwell, 2006). Several studies performed on silicate glasses and liquids have demonstrated that anhydrous chemical composition and water, the most abundant volatile in magmatic systems, strongly affect the structure (e.g., Mysen et al, 1982;Stolper, 1982a,b;Mysen, 1997;Mercier et al, 2009;Xue, 2009), the physical properties (viscosity, diffusivity, density, heat capacities; Persikov et al, 1990;Ochs and Lange, 1999;Whittington et al, 2000Whittington et al, , 2009Romano et al, 2001;Bouhifd et al, 2006;Vetere et al, 2007;Behrens and Zhang, 2009;Giordano et al, 2009;Fanara et al, 2012;Di Genova et al, 2013, 2014, the phase relationships and crystallization behavior of magmas (Fenn, 1977;Muncill and Lasaga, 1988;Davis et al, 1997;Vona and Romano, 2013).…”

Section: Introductionmentioning

confidence: 99%

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Genova

Romano

Giordano

et al. 2014

Geochimica et Cosmochimica Acta

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International audienceThe glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results

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“…Studies of magma mixing have long recognized that mixing textures and compositional zoning result from the interaction between two magmas with different temperatures, compositions, densities, viscosities, and solidii (e.g., Eichelberger 1980;Koyaguchi 1985;Bacon 1986;Campbell and Turner 1986;Koyaguchi 1986;Campbell and Turner 1989;Koyaguchi and Blake 1989;Jellinek et al 1999;Blake and Fink 2000;Snyder 2000;Coombs et al 2003;Humphreys et al 2006;Martin et al 2006). Injection of one magma into another, thermal and compositional contrasts of the magmas, and buoyancy forces can drive mixing between the two magmas (Eichelberger 1980;Freundt and Tait 1986;Clynne 1999;Blake and Fink 2000;Snyder 2000;Coombs et al 2003;Ruprecht et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Injection of one magma into another, thermal and compositional contrasts of the magmas, and buoyancy forces can drive mixing between the two magmas (Eichelberger 1980;Freundt and Tait 1986;Clynne 1999;Blake and Fink 2000;Snyder 2000;Coombs et al 2003;Ruprecht et al 2008). Viscosity contrasts and solidification inhibit mixing Blake and Fink 2000;Martin et al 2006;Hodge and Jellinek 2012;Hodge et al 2012a, b).…”

Section: Introductionmentioning

confidence: 99%

Thermal and rheological controls on the formation of mafic enclaves or banded pumice

Andrews

Manga

2014

Contrib Mineral Petrol

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Magma mixing can occur in a fluid manner to produce banded pumice or in a brittle manner to form enclaves. We propose that the critical control on mixing style is a competition between developing networks of crystals in the intruding magma that impart a strength to the magma and melting and disrupting those networks in the host. X-ray computed tomography analysis demonstrates that banded pumice from the 1915 Mt. Lassen eruption lacks crystal networks. In contrast, rhyodacite hosts with mafic enclaves from Chaos Crags contain welldeveloped networks of large crystals. We present a onedimensional conductive cooling model that predicts mixing style, either ductile or brittle, as a function of magma compositions, temperatures, and the size of the intruding dike. Our model relies on three assumptions: (1) Mixing is initiated by the injection of a hot dike into a cooler magma body with a yield strength; (2) when magma crystallinity exceeds a critical value, 13 vol% plagioclase, the magma develops a yield strength; and (3) when total crystallinity exceeds 40 vol%, the magma has a penetrative crystal network and is effectively solid. Importantly, because the two magmas are of different compositions, their crystallinities and viscosities do not have the same variations with temperature. As the intruding magma cools, it crystallizes from the outside in, while simultaneously, host magma temperature near the intruder rises. Mixing of the two magmas begins when the host magma is heated sufficiently to (1) disrupt the crystal network and (2) initiate convection. If the shear stress exerted by the convecting host magma on the dike is greater than the yield strength of the dike margin (and dike crystallinity does not exceed 40 %), then fluid mixing occurs, otherwise enclaves form by brittle deformation of the dike. Application of the model to magma compositions representative of Lassen and Chaos Crags shows that emplacement of dikes \1 m thick should produce enclaves, whereas thicker dikes should generate fluid mixing and form banded pumice within days to weeks of emplacement. Similar relationships apply to other modeled magmatic systems, including Pinatubo, Unzen, and Ksudach/Shtuybel' volcanoes. For all studied systems, the absolute size of the intruding dike, not just its proportion relative to the host, influences mixing style.

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Thermal effects of the intrusion of basaltic magma into a more silicic magma chamber and implications for eruption triggering

Cited by 114 publications

References 58 publications

On the conditions of magma mixing and its bearing on andesite production in the crust

On the conditions of magma mixing and its bearing on andesite production in the crust

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Thermal and rheological controls on the formation of mafic enclaves or banded pumice

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