lava of what composition is thicker or more viscous and has a higher silica content

Lava Of What Composition Is Thicker Or More Viscous And Has A Higher Silica Content?

Felsic lavas

What type of lava has the highest silica content?

What type of magma has the greatest silica content?

As a result of its higher viscosity and gas content, intermediate magma builds up pressure below the Earth’s surface before it can be released as lava.
Felsic magma has the highest silica content of all magma types, between 65-70%.

What type of lava has very high viscosity and high silica content?

The magma types vary from mafic magmas, which have relatively low silica and high Fe and Mg contents, to felsic magmas, which have relatively high silica and low Fe and Mg contents.

Which composition has the highest silica content?

Felsic rocks have the highest content of silica, and are predominantly composed of the felsic minerals quartz and feldspar. These rocks (granite, rhyolite) are usually light coloured, and have a relatively low density.

Which composition is silica rich and very viscous?

Rhyolite is an igneous volcanic rock of felsic (silica-rich) composition. Due to high silica content rhyolite lava is very viscous & flows slowly and tends to pile up and form lava domes.

Which type of magma has the highest viscosity?

rhyolitic magma The magma that has the highest viscosity is rhyolitic magma.

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What type of magma has the lowest viscosity highest viscosity?

Rhyolitic Rhyolite Rhyolitic magmas tend to have even higher viscosity, ranging between 1 million and 100 million times more viscous than water.

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Viscosity of Magmas.

Summary Table	Magma Type	Rhyolitic
	Solidified Rock	Rhyolite
	Chemical Composition	65-75 SiO₂ %, low in Fe, Mg, Ca, high in K, Na.
	Temperature	650 – 800 oC
	Viscosity	High

Does lava have high viscosity?

Even though lava is 100,000 times more viscous than water, it can still flow great distances. When lava has low viscosity, it can flow very easily over long distances. … But most importantly, highly viscous lava is associated with explosive eruptions and dangerous pyroclastic flows.

Does low viscosity lava have low silica content?

Composition: he more felsic the lava (the more silica in the lava), the higher the viscosity because silica forms chains in the cooling lava even before it crystallizes. The more mafic the lava (the less silica in it), the lower the viscosity.

Which type of magma has the highest silica content and viscosity the least silica content and viscosity?

Felsic magma Felsic magma has the highest silica content of all magma types, between 65-70%. As a result, felsic magma also has the highest gas content and viscosity, and lowest mean temperatures, between 650o and 800o Celsius (1202o and 1472o Fahrenheit).

What type of magma has the lowest silica content the highest?

Which magma type has the most silica the least silica? BASALTIC magmas have a LOW SILICA content (45-55%) and referred to as MAFIC in composition. RHYOLITIC magma contains more than 65% SILICA and is referred to as FELSIC. ANDESITIC magma is INTERMEDIATE in composition (55-65% SILICA).

Which magma composition contains the most silica SiO2 and therefore has the highest viscosity?

Granitic magma is thick and stiff and contains lots of silica and dissolved gasses. Granitic magma has the most silica and has the highest viscosity. 34) andesitic magma Andesetic magma has an intermediate amount of silica which gives it an intermediate viscosity, in between basaltic and granitic magmas.

Which chemical component of magma has the highest content?

Oxygen, the most abundant element in magma, comprises a little less than half the total, followed by silicon at just over one-quarter. The remaining elements make up the other one-quarter. Magmas derived from crustal material are dominated by oxygen, silicon, aluminum, sodium, and potassium.

How does silica affect the viscosity of magma?

Higher silica content means higher viscosity. But lower temperatures and low gas content mean higher viscosity. Hence, lower viscosity and low gas content mean higher temperature of magma.

What is the composition of lava?

Lava is mostly made of two elements — Si (the symbol for silicon) and O (the symbol for oxygen). Together, they make a very strong bond and then get together with other elements, like Fe (iron), Mg (magnesium), K (potassium), Ca (calcium), and more.

Which of the following lava compositions has the greatest amount of viscosity?

Viscosity is determined by its composition and temperature: Felsic lava is more viscous than mafic lava. Hotter liquids are less viscous than cold ones (put honey into the fridge and see how it flows and compare to honey at room temperature).

Which of the following increases the viscosity of magma?

The viscosity of magma increases with: high % silica and cooler temperatures.

What are the top two compositions of magma?

Magma Composition

Mafic magmas are low in silica and contain more dark, magnesium- and iron-rich mafic minerals, such as olivine and pyroxene.
Felsic magmas are higher in silica and contain lighter colored minerals such as quartz and orthoclase feldspar.

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What is the silica content?

silica, also called silicon dioxide, compound of the two most abundant elements in Earth’s crust, silicon and oxygen, SiO₂. The mass of Earth’s crust is 59 percent silica, the main constituent of more than 95 percent of the known rocks.

Which magma type is least viscous?

basalts Low-silica magmas are typically formed by partial melting of mantle rocks beneath mid-ccean ridges or at “hot spots” like Hawaii. These magmas erupt as basalts or intrude as gabbro, and are far less viscous.

What is fluid viscosity?

viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. Viscosity denotes opposition to flow. The reciprocal of the viscosity is called the fluidity, a measure of the ease of flow. Molasses, for example, has a greater viscosity than water.

Which of the following lavas typically has the lowest viscosity?

There are two types of lava flows, pahoehoe which is a ropy type of lava that flows easily (low viscosity).

What does it mean by higher silica content magma in terms of viscosity?

The higher the amount of silica in the magma, the higher is its viscosity. Viscosity is a liquid’s resistance to flow. Viscosity determines what the magma will do. Mafic magma is not viscous and will flow easily to the surface. Felsic magma is viscous and does not flow easily.

Which lava is more viscous acidic or basic?

Solution 1

Acidic Lava	Basic Lava
It is rich in silica and poor in iron and magnesium.	It is poor in silica and rich in iron and magnesium.

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Why does the viscosity of lava vary between volcanoes?

Magmas that are more rhyolitic have a higher gas content. This gas content and relative viscosity leads to the more explosive and violent eruptions that occur at composite volcanoes. In general, SiO2 content controls the relative viscosity of a magma. Viscosity is the ability of a liquid to resist flowing.

Do composite volcanoes have high silica?

A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. … The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma.

Which characteristic of lava has the greatest effect on its viscosity?

Higher silica increases viscosity. Magmas that have a high silica content will therefore exhibit greater degrees of polymerization, and have higher viscosities, than those with low-silica contents.

How does the composition temperature and viscosity of lava differ between composite volcanoes and shield volcanoes?

How does the composition and viscosity of lava flows differ between composite volcanoes and shield volcanoes? Composite volcanoes tend to have intermediate to felsic lava that is very viscous whereas shield volcanoes have basaltic lava that is low in viscosity.

What is the difference between the composition of lava and magma?

Magma is composed of molten rock and is stored in the Earth’s crust. Lava is magma that reaches the surface of our planet through a volcano vent.

When magma has a high viscosity How is it most likely to erupt?

A high viscosity magma will flow more readily and easily than a low viscosity magma. Therefore the eruption will be fluid and passive. A high viscosity magma will flow more readily and easily than a low viscosity magma. Therefore the eruption will be explosive.