What happens when magma is high in 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.
When a magma has a high viscosity that means that the magma has?
Describe magma with a high viscosity. Magma with a high viscosity is cooler in temperature, has a high amount of silica, and is Granitic/Andesitic.
How does temperature affect magma viscosity?
MAGMA VISCOSITY, TEMPERATURE, AND GAS CONTENT. The effect of temperature on viscosity is intuitive. Like most liquids, the higher the temperature, the more fluid a substance becomes, thus lowering its viscosity. Composition plays an even greater role in determining a magma’s viscosity.
How does temperature affect the viscosity of magma?
Why does silica increase the viscosity of magma?
As the magma cools, more and more bonds are created, which eventually leads to the development of crystals within the liquid medium. 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 of magma affect its 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. The amount of dissolved gasesin the magma can also affect it’s viscosity, but in a more ambiguous way than temperature and silica content.
What is the percentage of silica in felsic magma?
The percentage of silica in felsic magma is between 65% and 70%, and, because of this, it also has the highest viscosity (gooiness) and gas content. Of course, it also has low mean temperatures compared to other types of magma, with numbers that range from 1202ᵒ and 1472ᵒ Fahrenheit.
How is intermediate magma different from felsic magma?
You can see a large caldera in Yellowstone Park, and these craters are usually formed when the magma chamber of a volcano becomes empty. Although it doesn’t have a silica content that is as high as felsic magma, intermediate magma is roughly 60% silica, so it still contains a lot of silica.
Where does a low silica magma erupt from?
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.
