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High-silicate magma, also known as "felsic magma", is molten rock below the Earth's surface (or that of any other planet, I suppose) that is made up 70% or more silica (silicon dioxide).
Compared with other compositions of magma (andesitic, mafic, ultramafic) felsic is often cooler and more viscous, and so is associated with violent and explosive volcanism. Rocks formed from felsic magma include granite and rhyolite, their porphyritic relatives, granite pegmatite, rhyoltic tuff, pumice, and obsidian.
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Which of the following causes a magma to be less viscous?
fewer silicate chains in the magma
What is a low-silica magma?
A magma containing not much silica (= SiO2). For example: a basaltic magma. These magma's have a low viscosity since the lower the SiO2-content, the lower the viscosity; and hence flow easily (↔ a felsic magma).
What are the main ingredients of magma?
Magma is composed of molten silicate minerals, dissolved gasses, and sometimes crystallized minerals.
Magma that contains SiO2?
All magma contains SiO2. What affects magma is the amount of SiO2 in it. Magma is classified into four basic groups that can be determined by how much silica it contains by weight. Felsic: >63% SiO2 Untermediate: 52-63% SiO2 Mafic: 45-52%SiO2 Ultramafic: <45% SiO2 This spectrum is a basic guide to silicate magmas, which encompass that vast majority of magma. One exception is rare carbonatite magma, which is carbonate rather than silicate based, and even that contains some SiO2.
What causes different crystal shapes?
Crystals are made from molten magma that cools causing silicate minerals to crystallize. The different crystal shapes form differently as the magma cools at different rates.
What determines the strength of a eruption?
The temperature, the pressure, and the type of magma. High silicate magmas generally erupt explosively.
Which of the following causes a magma to be less viscous?
fewer silicate chains in the magma
Is felcite a metamorphic rock?
There is no individual rock called felcite. Felsic and felsitic are adjectives used to describe an igneous rock or magma that is particularly high in silicate minerals.
What is a low-silica magma?
A magma containing not much silica (= SiO2). For example: a basaltic magma. These magma's have a low viscosity since the lower the SiO2-content, the lower the viscosity; and hence flow easily (↔ a felsic magma).
What are the main ingredients of magma?
Magma is composed of molten silicate minerals, dissolved gasses, and sometimes crystallized minerals.
Magma that contains SiO2?
All magma contains SiO2. What affects magma is the amount of SiO2 in it. Magma is classified into four basic groups that can be determined by how much silica it contains by weight. Felsic: >63% SiO2 Untermediate: 52-63% SiO2 Mafic: 45-52%SiO2 Ultramafic: <45% SiO2 This spectrum is a basic guide to silicate magmas, which encompass that vast majority of magma. One exception is rare carbonatite magma, which is carbonate rather than silicate based, and even that contains some SiO2.
Is it true For molten rock to be considered a magma it must be intrusive and silicate in composition?
No. Magma is simply the name for molten rock that has not yet been erupted; after eruption it is known as lava.
What conditions make for a violent volcanic eruption?
Magma with high silica content
Explain how the silica content of molten material affects the color of igneous rocks?
Silica in molten material tends to crystallise as quartz, which is white or mostly pale in colour. So felsic rocks (from silica-rich magma) tend to be pale, while mafic rocks (from silica-poor magma) tend to be dark in colour.
What causes different crystal shapes?
Crystals are made from molten magma that cools causing silicate minerals to crystallize. The different crystal shapes form differently as the magma cools at different rates.
What is a A high temperature silicate with a name that is based on its color?
leucite
What type of magma is primarily associated with high viscosity?
Granitic magma
