Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.

What is the magma composition of composite?

Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.

What is mafic lava composition?

Describes magma that contains lower amounts of silica and is generally less viscous and less gas-rich than silicic magma. Tends to erupt effusively, as lava flows. Includes andesites (57-63 percent SiO2), basaltic andesites (53-57 percent SiO2), and basalts (47-53 percent SiO2).

Do composite volcanoes have mafic magma?

Composite cones are built of felsic to intermediate lava and shield volcanoes of mafic lava. Cinder cones are made of small fragments of a variety of compositions usually from a single eruption.

What composition Do composite volcanoes have?

Composition of composite volcanoes Composite volcanoes are typically composed of layers of pyroclastic material. The layers that form the mountain are lava, volcanic ash, tephra, and pumice. Andesite, dacite and rhyolite lavas erupted by these volcanoes have a high percentage of quartz and feldspar minerals.

Are composite volcanoes explosive or effusive?

Composite volcanoes are tall, steep cones that produce explosive eruptions. Shield volcanoes form very large, gently sloped mounds from effusive eruptions.

What are the characteristics of composite volcano?

Composite volcanoes have the following characteristics:

  • Acidic lava, which is very viscous (sticky).
  • Steep sides as the lava doesn’t flow very far before it solidifies.
  • Alternate layers of ash and lava. For this reason, they’re also known as stratovolcanoes .
  • Violent eruptions.
  • Longer periods between eruptions.

What are the 3 composition of magma?

The composition of the gases in magma are: Mostly H2O (water vapor) & some CO2 (carbon dioxide) Minor amounts of Sulfur, Chlorine, and Fluorine gases.

What are the two compositions of magma?

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 is magma formed in continental rift zones?

These landscapes are a result of continental rifting, or places where the continental crust is extending and thinning. As the crust thins, the hot, buoyant upper mantle (the asthenosphere) rises. Eventually the asthenosphere upwells so close to the surface that magma that erupts onto the surface.

What volcanoes have mafic magma?

Mafic lava flows can travel quite far before solidifying completely, and the type of volcano that forms from mafic lava is called a shield volcano (Figure 9.9). Shield volcanoes are very broad at the base and have relatively gentle slopes.

What type of magma does composite volcanoes have?

Andesitic magma
Composite volcanoes have the following characteristics: Andesitic magma, which is lower in temperature, has more silica and a lot of dissolved gases and is more likely to explode when it reaches the surface. Acidic lava, which is very viscous (sticky). Steep sides as the lava doesn’t flow very far before it solidifies.

What are the 3 characteristics of a composite volcano?

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

What is the composition of igneous rocks and magma?

The words that describe composition of igneous rocks also describe 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.

What is the difference between felsic and mafic magma?

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. Most felsic magma will stay deeper in the crust and will cool to form igneous intrusive rocks such as granite and granodiorite.

What are composite volcanoes?

Composite volcanoes are normally associated with subduction, and while their magma tends to be intermediate on average, it can range all the way from felsic to mafic. The corresponding differences in magma viscosity lead to significant differences in eruptions style.