Results 211 to 220 of about 23,398 (258)

Magma Emplacement and Accumulation: From Sills to Magma Chambers

2021
The previous chapter has discussed the rise of magma throughout the crust. This fourth chapter focuses on the arrest, emplacement and accumulation of magma. These are indeed primary and widespread processes at volcanoes, as most of the rising magma remains stalled in the crust, with only a fraction being erupted (approximately one tenth; e.g., Shaw ...
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Vibro-agitation of chambered magma

Journal of Volcanology and Geothermal Research, 2007
Abstract We present the results of a novel set of calculations into the effect of in situ pressure reduction of a crystal-rich, basaltic magma layer by propagating seismic (P) waves. Three stages in the process are identified. Critically, an instability can arise such that a low pressure melt layer develops close to the floor in initially densely ...
M. Davis, M.A. Koenders, N. Petford
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Magma mixing and convective compositional layering within the Vesuvius magma chamber

Bulletin of Volcanology, 1991
The pumice-fall deposits of the last two Plinian eruptions of Vesuvius-a.d. 79 “Pompei” and 3700 b.p. “Avellino”-show a marked vertical compositional variation from white phonolite at the base to grey tephritic phonolite at the top. In both Avellino and Pompei sequences a compositional gap separates white from grey pumice.
CIVETTA L, GALATI R, SANTACROCE, ROBERTO
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Dynamics of Magma Chambers

1993
Discussed herein are three major issues of debate regarding the dynamics of magma chambers: I. whether or not crystal settling is important II. whether or not magma densities drop during fractionation, and III. whether there is a Soret effect.
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Convection and Macrosegregation in Magma Chambers

1992
Magmas accumulate in large reservoirs where convection occurs, driven by density differences due to fractional crystallization and temperature variations. The observations consist of igneous rocks representing the final crystallized product and volcanic lava series.
S. R. Tait, C. Jaupart
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Mid‐ocean ridge magma chambers

Journal of Geophysical Research: Solid Earth, 1992
Geophysical evidence precludes the existence of a large, mainly molten magma chamber beneath portions of the East Pacific Rise (EPR). A reasonable model, consistent with these data, involves a thin (tens to hundreds of meters high), narrow (<1–2 km wide) melt lens overlying a zone of crystal mush that is in turn surrounded by a transition zone of ...
John M. Sinton, Robert S. Detrick
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Simulation of Layered Magma Chambers

Journal of Geological Education, 1991
The principles of magma addition and liquid layering in magma chambers can be simply demonstrated in the laboratory by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature.
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Volcanoes, Volcanic Rocks and Magma Chambers

1984
Volcanoes are hills, mounds or sheets of relatively localized igneous rock assemblages made up of pyroclastic rocks, lava flows, and intrusions in varying proportions. Volcanoes differ notably in their geometry, volume, and relative amounts of pyroclastic rocks and lava flows, with differences mostly dependent upon eruptive mechanisms and rates of ...
Richard V. Fisher, Hans-Ulrich Schmincke
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Fountains in Magma Chambers

Journal of Petrology, 1989
I. H. CAMPBELL, J. S. TURNER
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Slimline magma chambers

Nature, 1992
Sherman Bloomer, Peter Meyer
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