Rheology of subliquidus magmas: 1. Picritic compositions

Ryerson, Frederick J.; Weed, H.C.; Piwinskii, A.J.

doi:10.1029/jb093ib04p03421

Cited by 188 publications

(149 citation statements)

References 71 publications

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“…Each session records the variation of viscosity at a constant rotation rate of the rod. Usually, the first session records a marked decrease of viscosity, which may be due to shear heating, the tendency for parallel alignment of plagioclase plates, or the tendency for melt to climb the rod (Shaw, 1969;Spera et al, 1988;Ryerson et al, 1988). The significance of the temporal variations of viscosity in each session will be discussed later.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…This points to the importance of the crystal shape on the rheological properties of crystal suspensions. Ryerson et al (1988) noted the presence of yield strength in Hawaiian picrites, in which near spherical olivine was crystallized in abundance. The present work utilized a rotational viscometer with constant rotation rate, so that it did not afford data on the yield strength of magma with plagioclase plates.…”

Section: Non-newtonian Behavior Of the Basaltic Meltmentioning

confidence: 99%

“…Open circles illustrate the temperature effect on the viscosity of melt, calculated for the bulk composition at each temperature after the equation of Shaw (1972). Subliquidus viscosity of Hawaiian picritic tholeiite (crosses) is after the experiments of Ryerson et al (1988). Dark areas with dots of darker pits are the alumina rods used for the viscometry and sampling.…”

Section: Viscosity Measurementsmentioning

confidence: 99%

“…Pinkerton and Stevenson (1992), among others, reviewed the methods of correction to obtain the bulk viscosity for melt + crystal systems and indicated that crystal size distribution and the aspect ratio of crystals, in addition to the proportion of crystalline matter, greatly affect the bulk rheological properties of magmas. Previous experimental studies of subliquidus viscometry on basaltic magmas mostly pay little attention to the composition and textures of the crystals and melts (Shaw, 1969;Ryerson et al, 1988;Pinkerton and Norton, 1995). In the present study, we installed a new rotational viscometer to operate at high temperature and one atmosphere under controlled oxygen fugacity, which allows temporal sampling of the melt + crystal at the time of the viscosity measurement.…”

Section: Introductionmentioning

confidence: 99%

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Viscosity measurement of subliquidus magmas: 1707 basalt of Fuji volcano

Sato

2005

Journal of Mineralogical and Petrological Sciences

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We have installed a new furnace equipped with a rotational viscometer for use in viscometry at high temperature (one atmosphere) under controlled oxygen fugacities. This furnace allows sampling at the time of the viscosity measurement. Utilizing this furnace, we examined the relationship between textural parameters (crystallinity and the apparent aspect ratio of crystals) and viscosity during cooling of a basaltic magma. The 1707 basalt from Fuji volcano was used for the experiment and the result shows a drastic increase in viscosity from the liquidus temperature (1230°C; η = 52 Pa s), through 1170°C (crystallinity = 11%; η = 350 Pa s), to 1130°C (crystallinity = 23%; η = 1950 Pa s). The increase in viscosity during cooling is affected by both the increase of the crystallinity and the change of melt composition as a result of crystallization. For the basalt from Fuji volcano, crystallization of thin tabular plagioclase enhanced the strong effect of crystal entanglement, whereas the changes of melt compositions did not affect the viscosity because of the increase of ferromagnesian components and the decrease of feldspathic component in the residual liquid during crystallization. The effect of the presence of crystals on the viscosity is much larger than that expected from the Einstein Roscoe equation with Marsh's constant (η = η0 (1 − ϕ/0.6) 2.5 ), where ϕ denotes the crystal fraction. The additional correction of Simha on the solid shape parameter slightly overestimates the increase in relative viscosity in the presence of thin platy crystals. A shear rate dependence of the viscosity was observed at lower temperature crystal rich conditions.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Non-newtonian Behavior Of the Basaltic Meltmentioning

confidence: 99%

Section: Viscosity Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Viscosity measurement of subliquidus magmas: 1707 basalt of Fuji volcano

Sato

2005

Journal of Mineralogical and Petrological Sciences

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“…The rheological properties of a disperse magmatic system are not well known and this study is one of the first steps in that direction. Previous studies have concerned the cases of crystal + melt suspensions (Ryerson et al, 1988) and of dilute emulsions of melt + bubbles (Stein and Spera, 1992). The application of experimental results obtained on simple suspensions, such as Newtonian liquid+non-deformable spheres to magma flows may, however, ignore non-Newtonian effects specific to highly viscous dilatant fluids at low strain rates.…”

Section: Introductionmentioning

confidence: 99%

A rheological investigation of vesicular rhyolite

Bagdassarov

Dingwell

1992

Journal of Volcanology and Geothermal Research

137

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Res., 50: 307-322.The rheology of vesiculating rhyolitic systems exerts a strong control on the transport of silicic magmas in the subvolcanic to volcanic environments. We present here an investigation of vesiculating and vesiculated rhyolites using dilatometric methods. This study examines the effect of vesicle content on the viscosity of a natural supercooled rhyolitic liquid with 0-70% vesicles.The experimental samples of rhyolitic glass are derived from fusion of a natural obsidian from Little Glass Butte, Oregon. Crystal-free rhyolite glasses of varying porosity were prepared by fusing obsidian powder in a Pt crucible. Differing porosities were obtained by varying the temperature (1300-1650°C) and duration (0.5-6 h) of the fusions. Cylindrical samples of the resulting vesiculated rhyolites were cored from the crucible using diamond tools and their ends were ground flat and parallel for dilatometry. The porosity of each sample was determined from Archimedean buoyancy density determinations and comparison with bubble-free rhyolite (2.331 g/cm 3, porosity= 1 -P/Po). The density of foamed samples was determined using their mass, volume and regular geometry.Viscosities were determined in the parallel plate mode at stresses of 5 × 103 to 105 Pa. The viscosimeter was calibrated using NBS 711 glass. The bubble contents were microscopically investigated using a video-reflected light system and image analysis software. Distribution functions of the size, orientation, aspect ratio and surface porosity were obtained.The viscosity of rhyolite decreases with increasing bubble content. A general relationship of the form: r/(f) = q(0)/ ( 1 + CJ), describes the effect of porosity, f (in volume fraction) on the viscosity, q, where C is a dimensionless constant (=22.4+_2.9) and logmr/(0) = 10.94+0.04 Pa s at 850°C.

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Effects of crystal shape‐ and size‐modality on magma rheology

Moitra

Gonnermann

2015

Geochem Geophys Geosyst

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Erupting magma often contains crystals over a wide range of sizes and shapes, potentially affecting magma viscosity over many orders of magnitude. A robust relation between viscosity and the modality of crystal sizes and shapes remains lacking, principally because of the dimensional complexity and size of the governing parameter space. We have performed a suite of shear viscosity measurements on liquid-particle suspensions of dynamical similarity to crystal-bearing magma. Our experiments encompass five suspension types, each consisting of unique mixtures of two different particle sizes and shapes. The experiments span two orthogonal subspaces of particle concentration, as well as particle size and shape for each suspension type, thereby providing insight into the topology of parameter space. For each suspension type, we determined the dry maximum packing fraction and measured shear rates across a range of applied shear stresses. The results were fitted using a Herschel-Bulkley model and augment existing predictive capabilities. We demonstrate that our results are consistent with previous work, including friction-based constitutive laws for granular materials. We conclude that predictions for ascent rates of crystal-rich magmas must take the shear-rate dependence of viscosity into account. Shear-rate dependence depends first and foremost on the volume fraction of crystals, relative to the maximum packing fraction, which in turn depends on crystal size and shape distribution.

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Rheology of subliquidus magmas: 1. Picritic compositions

Cited by 188 publications

References 71 publications

Viscosity measurement of subliquidus magmas: 1707 basalt of Fuji volcano

Viscosity measurement of subliquidus magmas: 1707 basalt of Fuji volcano

A rheological investigation of vesicular rhyolite

Effects of crystal shape‐ and size‐modality on magma rheology

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