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

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

Siliceous Lava Flows – High viscosity andesitic and rhyolitic lava flows, because they can’t flow very easily, form thick stubby flows that don’t move far from the vent.

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%.

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.

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Is thick lava high in silica?

Volcanic Eruptions: High Silica Lava with high silica content is thick and viscous and does not readily flow. Lava rises up toward the surface but is too thick to squeeze through the cracks and fissures in the Earth. As lava continues to rise upward, pressure continues to build.

Does a shield volcano have high or low silica?

Shield volcanoes have the following characteristics: Basaltic magma, which is high in temperature, very low on silica and with low gas content. This type of magma produces fluid lava with very little explosive activity.

Which volcano type is the most explosive due to high gas and silica content in their lava?

Rhyolite Caldera Complexes Are Central Vent Volcanoes. High-silica, high-gas magmas. Massive explosions (most explosive of all types).

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

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. The higher the amount of silica in the magma, the higher is its viscosity.

Which type of rock has the greatest 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.

What is magma with a low silica content called?

Mafic magma has relatively low silica content, roughly 50%, and higher contents in iron and magnesium. This type of magma has a low gas content and low viscosity, or resistance to flow.

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Which type of igneous rocks based on composition has the highest amount of silica content?

Silica content Acid: rocks with above 63% silica (mostly feldspar minerals and quartz), e.g. granite. Basic: rocks that are about 45 to 55% silica (mostly mafic minerals plus plagioclase feldspar and/or feldspathoid minerals), e.g. basalt.

Which type of magma has the highest temperature?

Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium. It ranges in temperature from about 1000oC to 1200oC (1832oF to 2192oF).

What does silica do to lava?

Silica: Influences lava viscosity and overall shape of the volcano. Silica molecules form a strong bond that permits entrapment of volcanic gases and promotes explosive volcanic eruptions. Low-silican magmas allow rapid escape of gases and low-explosivity eruptions.

Is lava hotter than fire?

While lava can be as hot as 2200 F, some flames can be much hotter, such as 3600 F or more, while a candle flame can be as low as 1800 F. Lava is hotter than a typical wood or coal-buring fire, but some flames, such as that of an acetylene torch, is hotter than lava.

What is high silica magma?

Magmas that have a high silica content will therefore exhibit greater degrees of polymerization, and have higher viscosities, than those with low-silica contents. The amount of dissolved gases in the magma can also affect it’s viscosity, but in a more ambiguous way than temperature and silica content.