Results 181 to 190 of about 82,590 (220)
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Magmas in collision: Rethinking chemical zonation in silicic magmas
Geology, 2000The heterogeneity of eruptions attributed to protracted fractionation in subvolcanic magma chambers may instead result from chamber recharge. The case of mafic magma intruding andesitic slush is recognized as giving rise to hybrid effusive eruptions such as at Unzen volcano, Japan, and Soufriere Hills volcano, Montserrat. We propose that zoned andesite-
Christopher J. Nye +3 more
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Dynamic Magma Systems: Implications for Forecasting Volcanic Activity
, 2017Magma systems that supply volcanoes can extend throughout the crust and consist of mush (melt within a crystalline framework) together with ephemeral magma accumulations.
R. Sparks, K. Cashman
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Silicic Magmas (Magma Formation in the Crust)
1971In deeply eroded ancient fold regions, levels are exposed at which silicic magma was once generated. From the field of abyssal geology proper, we now move over to conditions of investigation more customary to us, and it may be comparatively easy to draw some conclusions.
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Temperature of Vesuvius magmas
Geology, 1999Melt inclusions in Ca-pyroxenes from pyroclasts of several Vesuvius eruptions show that pyroxenes (Wo 46–48 -En 45–50 to Wo 50–52 -En 20–25 ) formed in shallow reservoirs from K-basalt and/or K-tephrite to K-phonolite magmas over a wide temperature range (800–1200 °C).
Cioni R +2 more
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Gradients in silicic magma chambers: Implications for lithospheric magmatism
, 1981Every large eruption of nonbasaltic magma taps a magma reservoir that is thermally and compositionally zoned. Most small eruptions also tap parts of heterogeneous and evolving magmatic systems.
W. Hildreth
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Science, 1974
Oxygen isotope analyses of sanidine phenocrysts from rhyolitic sequences in Nevada, Colorado, and the Yellowstone Plateau volcanic field show that δ 18 O decreased in these magmas as a function of time. This decrease in δ 18 O may have been caused by isotopic exchange between the magma and ...
Jim D. Gleason +4 more
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Oxygen isotope analyses of sanidine phenocrysts from rhyolitic sequences in Nevada, Colorado, and the Yellowstone Plateau volcanic field show that δ 18 O decreased in these magmas as a function of time. This decrease in δ 18 O may have been caused by isotopic exchange between the magma and ...
Jim D. Gleason +4 more
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Magma Production Rates for Intraoceanic Arcs
, 2015Intraoceanic volcanic arcs have long been recognized as sites where continental crust is created. Yet, despite their importance to understanding magmatic systems and the evolution of our planet, very little is known about their long-term rates of magma ...
B. Jicha, O. Jagoutz
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Magma oceans in the inner solar system
, 2012Theory and observations point to the occurrence of magma ponds or oceans in the early evolution of terrestrial planets and in many early-accreting planetesimals.
L. Elkins‐Tanton
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The Leading Edge, 1983
Magma, or molten rock, is the ultimate heat source for geothermal fields. In conventional geothermal applications the energy from magma is tapped indirectly in natural geothermal fields usually associated with magma bodies. Many magma sources, however, lack an adequate geothermal field for exploitation. Enormous quantities of energy are stored in magma
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Magma, or molten rock, is the ultimate heat source for geothermal fields. In conventional geothermal applications the energy from magma is tapped indirectly in natural geothermal fields usually associated with magma bodies. Many magma sources, however, lack an adequate geothermal field for exploitation. Enormous quantities of energy are stored in magma
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Geological Magazine, 1969
SUMMARYBreadcrust blocks (bombs) on Vulcano, Sicily, show features which indicate that when they were of viscous lava they broke when stress was applied rapidly, and later flowed when it was applied slowly. If the magma of granitic intrusions behaves similarly, the perplexing “relict dykes” can be explained as due to the breaking of the magma and the ...
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SUMMARYBreadcrust blocks (bombs) on Vulcano, Sicily, show features which indicate that when they were of viscous lava they broke when stress was applied rapidly, and later flowed when it was applied slowly. If the magma of granitic intrusions behaves similarly, the perplexing “relict dykes” can be explained as due to the breaking of the magma and the ...
openaire +2 more sources