Felsic magmas contain more silica and lighter colored minerals such as quartz and orthoclase feldspar. The higher the proportion of silica in magma, the higher its viscosity. Viscosity is the resistance to flow of a liquid. Viscosity determines how the magma behaves.
So what type of magma is considered an intermediate?
Magma types are determined by the chemical composition of the magma. Three general types are recognised: Basaltic magma – SiO245-55 wt%, rich in Fe, Mg, Ca, low in K, Na. Andesitic Magma – SiO255-65 wt%, intermediate.
And why are there so many types of magma?
Answer and explanation: There are many different types of magma because there are so many different minerals and chemical components that could form magma on Earth.
With that in mind, what composition of magma causes the most violent eruptions?
The largest and most violent of all types of volcanic eruptions are Plinian eruptions. They are caused by the fragmentation of gaseous magma and are usually associated with very viscous magmas (dacite and rhyolite).
What types of magma are there?
The high temperatures and pressures under the earth’s crust keeps magma in its liquid state. There are three basic types of magma: basaltic, andesitic, and rhyolitic magma, each with a different mineral composition. All types of magma have a significant amount of silica.
Which magma has the highest viscosity?
The magma with the highest viscosity is rhyolitic magma.
How is rhyolite formed?
Rhyolite is a volcanic rock. It is fine-grained because it forms from the rapid cooling of magma, usually when it erupts onto the Earth’s surface. When rhyolite quietly erupts, it forms lava flows. When it erupts explosively, it often forms pumice.
What are the two main factors that lead to more violent eruptions?
The two main factors that influence a volcano’s eruption are viscosity and gas content. Both are related to the composition of the magma. Hawaiian volcanoes tend to erupt basalt, which has low viscosity and low gas content (about 0.5 percent by weight).
How fast is magma ejected from the volcano?
The time The length of time between eruptions depends on how fast the rock is melting, which is affected by the speed of the sinking plate. The Earth has several subduction zones and the subducting plates generally move at a constant rate of up to 10 centimeters per year.
What causes explosive eruptions?
In volcanology, an explosive eruption a volcanic eruption of the most violent kind. Such eruptions occur when, under pressure, sufficient gas has dissolved in a viscous magma such that ejected lava foams violently into volcanic ash when the pressure at the vent is suddenly reduced.
Where are the different types of magma produced?
Three general types are recognized:
- Basaltic Magma — SiO245-55 wt%, rich in Fe, Mg, Ca, low on K, Na.
- Andesitic Magma — SiO255-65 wt%, intermediate. in Fe, Mg, Ca, Na, K.
- Rhyolitic magma — SiO265-75%, low Fe, Mg, Ca, high in K, Na.
Where is felsic magma formed?
The volcanoes that produce this type of eruption are powered by felsic magma. Felsic magma forms at lower temperatures and has a different chemical composition than mafic magma (see table above for comparison). The lower formation temperature reflects a shallower origin near the base of the lithosphere.
What does Plinian eruption mean?
Plinian eruptions, or Vesuvius eruptions, are volcanic eruptions characterized by their resemblance to the Eruption of Mount Vesuvius in AD 79, destroying the ancient Roman cities of Herculaneum and Pompeii. Plinian eruptions are often accompanied by loud noises, such as those produced by the Krakatoa eruption in 1883.
What types of eruptions are there?
There are two types of eruption activity , explosive eruptions and effusive eruptions. Explosive eruptions are characterized by gas-driven explosions that propel magma and tephra. Effusive eruptions, on the other hand, are characterized by the outpouring of lava without a significant explosive eruption.
What factors influence an eruption?
The nature of the eruption depends on a number of factors, including magma chemistry and grade, temperature, viscosity (how liquid the magma is), volume and how much water and gas it contains, the presence of groundwater and the volcano’s casing.
What is felsic magma like? formed?
When ultramafic magmas encounter the felsic rocks of the continental crust, they melt the most felsic minerals in those felsic rocks (those with the lowest melting point). Therefore, felsic material is added to the magma as mafic material is lost through fractional crystallization.
How much pressure does a volcano need to erupt?
Depending on how porous the rock is that is, the pressure required to trigger an eruption at Popocatépetl varies between about 50 atmospheres and 200 atmospheres. That cluster of blue stars on the right – they’re all around 50 atmospheres.
How is magma made?
Magma composition. Magma is primarily a very hot liquid called a melt. ‘ It is formed by the melting of rocks in the Earth’s lithosphere, the outermost layer of the Earth, which consists of the Earth’s crust and upper part of the mantle, and the asthenosphere, the layer below the lithosphere.
Is felsic magma explosive?
Explosive Eruptions. Felsic magma erupts explosively as hot, gas-rich magma is stirred up in its chamber. The pressure becomes so great that the magma eventually breaks the seal and explodes, just like a cork coming off a champagne bottle.
What are the properties of the magma that creates a supervolcano?
What are the characteristics of a supervolcano? Supervolcanoes are not mountains – they form depressions in the earth’s crust. They begin with a column of magma rising through a vent into the earth’s crust. The magma gets stuck and accumulates and melts the rock for thousands of years.
What are the two main factors that determine how magma erupts?
The two main factors that determine how magma erupts how magma erupts erupts is its viscosity and gas content. Define viscosity. The measure of the mobility of a liquid. The more viscous, the greater its resistance to flow.
What is felsic magma?
Felsic magma is molten rock (magma) with a high concentration of silica, sodium, and potassium (these are common ) in contrast to a mafic (dark) magma, which is typically richer in iron, magnesium and calcium. Felsic magmas are typically “stickier” than mafic magmas and lighter in color.