Results 211 to 220 of about 23,785 (261)

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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Properties of Carbonatite Magma and Processes in Carbonatite Magma Chambers

The Journal of Geology, 1983
The physical and thermal properties of carbonatite magmas are estimated by analogy with alkali carbonate melts, which are ionic liquids, composed of discrete, unpolymerized ions. Carbonatite magmas are estimated to have low viscosity (on the order of 5 × 10-2 poise), low heat of fusion (175 J/gm), and large thermal diffusivity (4 × 10-3 J/cm-sec-K ...
Allan H. Treiman, Andrew Schedl
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Evaluating volumes for magma chambers and magma withdrawn for caldera collapse

Earth and Planetary Science Letters, 2014
Article history: We develop an analytical model to infer the total volume of a magma chamber associated with caldera collapse and the critical volume of magma that must be withdrawn to induce caldera collapse. The diameter of caldera border fault, depth to the magma chamber, and volumes of magma erupted before the onset of collapse and of entire ...
Geshi N, Ruch J, ACOCELLA, Valerio
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Convection and mixing in magma chambers

Earth-Science Reviews, 1986
Abstract This paper reviews advances made during the last seven years in the application of fluid dynamics to problems of igneous petrology, with emphasis on the laboratory work with which the authors have been particularly involved. Attention is focused on processes in magma chambers which produce diversity in igneous rocks, such as fractional ...
J.S. Turner, I.H. Campbell
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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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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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Eruptions from zoned magma chambers

Journal of the Geological Society, 1981
SUMMARY: An appreciation of the positions within a magma chamber from which magma will be erupted can be gained from an understanding of the pattern of magma removal. Upwardly converging streamlines followed by a fluid escaping from a flat-topped reservoir into a cylindrical conduit cause magma from widely separated horizontal and vertical
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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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Crypto-magma chambers beneath Mt. Fuji

Journal of Volcanology and Geothermal Research, 2010
Abstract Mt. Fuji consists dominantly of basalt. A study of olivine-hosted melt-inclusions from layers of air-fall scoria, however, shows clear evidence of andesitic liquids. Whole rock compositions show a narrow range of SiO2, but a wide range of FeO*/MgO and incompatible elements.
Takayuki Kaneko, Atsushi Yasuda, Toshitsugu Fujii, Mitsuhiro Yoshimoto   +3 more
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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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