Page 367 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

349 andesite rocks guide,

Setting variety. The material basaltic igneous magma solidi- rough a is

Tectonic to specific the where type

fluid basalt where rock form.
more of indicate each rock that

the generally settings for of
of letters
is is tectonic case occurrence amounts
generally cones, the Lower The

air cinder to 2). substantial
the # refer mantle.
into forming LT chart (Chapter or where
high SETTING the crust settings
strewn down, on occur the
Cones Magma rains composition. Numbers commonly within fied indicating

Cinder that TECTONIC

degree, form occur the mag- minerals High- mag- viscos- much are but have but Sudden rhyolite of slopes rhyolite) slopes;

large therefore white) magnesium); # high-silica silica liquid. low-silica rivers. Low are magmas, therefore magma, to to (10°

a to silica. flow. (and magma. gentle
to magmas (pink and melts, lower higher still is than like to farther fluid magmas low-silica andesite with (andesite steeper
depend, iron rock cools, and magma paste-like flow and likely much from magmas. high-silica with much

chart Low-silica lighter colors with dense. As magma higher the of water is lava flow easily high-silica low-silica free-flowing, magmas volcanoes magmas
the those with while more far) silica). sticky, forming volcanoes
in minerals. (like more temperature. as how therefore escape viscosity than from of High-viscosity the

" depicted black, while minerals thus are Conversely, those by “stickiness”) form to therefore fountains (and will (high dioxide) High gasses escape within eruption freely, making

magma magma. colored to green rocks Temperature melting begin are like erupt easily silica) viscosity carbon sticky. trapped gasses pressure) violent flow volcanoes).
Rocks of the dark dark heavy igneous the first. progressively flow; (rhyolite/andesite) to how low high and are of cools, high causes (basalt) volcanoes,
Igneous MAGMA properties of more are increases. more lower the out come followed ~ to (tetrahedra) tend determines with with vapor magmas percentage Eruptions and (under Volcanoes magmas (“shield” of volcanoes).

OF content the silica, that rocks content the silica, resulting (Solidification) silica, (Resistance molecules (basalt), which Flows (those those than (water when higher rises pressure 2° sides the
AppendixC PROPERTIES physical The the silica on less The igneous silica less The and magma more The generally mas first, solidify Silica magmas silica mas Lava of viscosity The magmas ity thinner) Volatiles Volatiles trapped much Volcanic of magma As trapped are of release composition. of Major Low-viscosity to 1° only to stick “composite”

348 ’ Color. as Density Melting Viscosity Extent Percent a Types Types
°

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