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Do shield volcanoes contain mafic or felsic lava?
Yes. Many stratovolcanoes vary in the composition of what they erupt over time. They may cycle in the type of material. As the magma chamber cools, the magma somtimes becomes more felsic only to periodically receive and injection of fresh mafic magma from the mantle.
What do they call volcano formed by liquid rock?
There are two types of volcanoes formed by liquid rock (lava/magma), one being a shield volcano that are spread out over a large area but are not very tall because of the lava being mafic in nature (very liquid lava) such as the types of volcanoes that formed Hawaii, and the other being a composite volcano which is formed by felsic (thick) lava, making them steep and tall.
Is lava heterogeneous?
No, there are different types of lava. Most lavas are on a spectrum of compositions ranging from mafic to felsic. The classic image of lava is of basaltic lava such as that found in Hawaii. This is mafic lava, meaning that it has a low viscosity and a low silica content. Volcanoes that produce basaltic lava typically not not erupt very explosively. This is the most common type of lava. Basaltic lava can also be divided into two categories: pahoehoe which has a smooth, ropy texture and a'a, which forms a jagged surface. Next up on the spectrum is andesitic lava which is of intermediate composition, meaning it is more viscous and has a higher silica content. This lava is viscous enough that it has trouble flowing downhill. It usually has more gasses trapped in it (when it is underground, where it is called magma) and is often ejected in explosive eruptions. Further up is dacitic lava, which is of intermediate-felsic composition, meaning it is even more viscous and contains even more silica. It is so viscous that rather than flowing out of a volcano, it sometimes builds into a dome on top of the vent it comes out of. A number of volcanoes with dacitic compositions have produced very explosive eruptions including Mount St Helens and Mount Pinatubo. Then there is rhyolitic lava, which is felsic, meaning it has the highest viscosity and highest silica content. It is so viscous that has trouble reaching the surface, so the magma often cools underground, forming granite. Some very powerful volcanoes have erupted rhyolite, including the supervolcanoes at Yellowstone and Lake Toba.Two special kinds of lava should also be mentioned. The first is Komatiite, This lava is not mafic but ultramafic, meaning it has a lower silica content and viscosity than mafic lava. However, earth's interior is not longer hot enough to produce volcanoes with komatiite lava.The other kind of lava is carbonatite which is completely off the mafic-felsic spectrum of silicate lavas. Instead, this is the world's only known carbonate lava. It has a very low viscosity (due to the absence of silica) and a low melting temperature compared with other lavas. It is only found at one volcano: Ol Doinyo Lengai in Tanzania.
Why do mafic magmas tend to reach the surface much more often than silicic magmas?
Mafic magma is less viscous or more fluid than silicic magma in much the same way that water is less viscous than molasses. Mafic magma reaches the surface more often because it flows more easily.
Are there three types of lava or four?
It depends on what criteria you use. If you go with the kind of flow there are four.Pahoehoe (ropey lava flows)A'a (jagged, more viscous flows)Pillow lava (rounded lumps that form underwater)Block lava (very viscous, very slow moving)The first three are all associated with mafic lava, also called basaltic lava, which refers to a specific composition. Pillow lava is sometimes ignored as are black lava flows, which don't much resemble traditional images of lava.In terms of composition there are also 4 basic types on a spectrum of increasing silica content and viscosityMafic (basaltic)Intermediate (andesitic)Intermediate-felsic (dacitic)Felsic (rhyolitic)These can be further subdivided. Another, rare kind of lava exists called carbonatite. This strange lava is composed of carbobnates rather than silicates as the others are, and is only found in one volcano: Ol Doinyo Lengai in Tanzania.
Do shield volcanoes contain mafic or felsic lava?
Yes. Many stratovolcanoes vary in the composition of what they erupt over time. They may cycle in the type of material. As the magma chamber cools, the magma somtimes becomes more felsic only to periodically receive and injection of fresh mafic magma from the mantle.
What is the lithosphere made of mafic or felsic?
Its made up of both. Oceanic crust is mostly mafic magma (basalt) and continental crust is mafic and felsic. The lithosphere also contains the upper portion of the upper mantle which is mostly mafic. The earths crust is 60% Si02 (silicates). Felsic rocks are much more silicate heavy than mafic. So one would assume that the crust is more felsic than mafic. That's just my conceptual thought process so don't take me on my word. Then again, the lithosphere also contains the upper mantle which is heavily mafic. So maybe the lithosphere in total is more mafic? Basically just typing thoughts down as they enter my brain. Answer I know for certain- Lithosphere is mafic and felsic.
What do they call volcano formed by liquid rock?
There are two types of volcanoes formed by liquid rock (lava/magma), one being a shield volcano that are spread out over a large area but are not very tall because of the lava being mafic in nature (very liquid lava) such as the types of volcanoes that formed Hawaii, and the other being a composite volcano which is formed by felsic (thick) lava, making them steep and tall.
What is the odd one out of granite basalt sandstone?
Sandstone is the odd one out as it is a sedimentary rock, as opposed to granite and basalt which are respectively felsic and mafic igneous rocks.
Is lava heterogeneous?
No, there are different types of lava. Most lavas are on a spectrum of compositions ranging from mafic to felsic. The classic image of lava is of basaltic lava such as that found in Hawaii. This is mafic lava, meaning that it has a low viscosity and a low silica content. Volcanoes that produce basaltic lava typically not not erupt very explosively. This is the most common type of lava. Basaltic lava can also be divided into two categories: pahoehoe which has a smooth, ropy texture and a'a, which forms a jagged surface. Next up on the spectrum is andesitic lava which is of intermediate composition, meaning it is more viscous and has a higher silica content. This lava is viscous enough that it has trouble flowing downhill. It usually has more gasses trapped in it (when it is underground, where it is called magma) and is often ejected in explosive eruptions. Further up is dacitic lava, which is of intermediate-felsic composition, meaning it is even more viscous and contains even more silica. It is so viscous that rather than flowing out of a volcano, it sometimes builds into a dome on top of the vent it comes out of. A number of volcanoes with dacitic compositions have produced very explosive eruptions including Mount St Helens and Mount Pinatubo. Then there is rhyolitic lava, which is felsic, meaning it has the highest viscosity and highest silica content. It is so viscous that has trouble reaching the surface, so the magma often cools underground, forming granite. Some very powerful volcanoes have erupted rhyolite, including the supervolcanoes at Yellowstone and Lake Toba.Two special kinds of lava should also be mentioned. The first is Komatiite, This lava is not mafic but ultramafic, meaning it has a lower silica content and viscosity than mafic lava. However, earth's interior is not longer hot enough to produce volcanoes with komatiite lava.The other kind of lava is carbonatite which is completely off the mafic-felsic spectrum of silicate lavas. Instead, this is the world's only known carbonate lava. It has a very low viscosity (due to the absence of silica) and a low melting temperature compared with other lavas. It is only found at one volcano: Ol Doinyo Lengai in Tanzania.
Why do mafic magmas tend to reach the surface much more often than silicic magmas?
Mafic magma is less viscous or more fluid than silicic magma in much the same way that water is less viscous than molasses. Mafic magma reaches the surface more often because it flows more easily.
Are there three types of lava or four?
It depends on what criteria you use. If you go with the kind of flow there are four.Pahoehoe (ropey lava flows)A'a (jagged, more viscous flows)Pillow lava (rounded lumps that form underwater)Block lava (very viscous, very slow moving)The first three are all associated with mafic lava, also called basaltic lava, which refers to a specific composition. Pillow lava is sometimes ignored as are black lava flows, which don't much resemble traditional images of lava.In terms of composition there are also 4 basic types on a spectrum of increasing silica content and viscosityMafic (basaltic)Intermediate (andesitic)Intermediate-felsic (dacitic)Felsic (rhyolitic)These can be further subdivided. Another, rare kind of lava exists called carbonatite. This strange lava is composed of carbobnates rather than silicates as the others are, and is only found in one volcano: Ol Doinyo Lengai in Tanzania.
What three types of materials are ejected during a volcanic eruption?
The types of volcanic material include: - Lava : liquid rock (felsic or mafic magma) - Ash : pulverized or oxidized rock, the smallest particles of ejected rock - Gases : carbon dioxide, sulfur compounds, and water vapor - Pyroclastic flows : extremely hot gas and rock, typically flowing at hundreds of miles per hour. - Volcanic bombs : heavy masses of solid or liquid rock * Ash, pyroclastic particles, and bombs are collectively known as tephra.
Difference between viscous and non viscous lava?
Viscous lava is very sticky and thick and is more felsic (ie it contains more silica) than non-viscous lava. This type of lava makes for a very explosive volcano, because it's so sticky that it sticks to itself and can't exit the volcano until it explodes violently. Non-viscous lava is more runny and is more mafic (has more iron, less silica). Volcanoes with non-viscous lava are less explosive because the lava just runs out slowly and no pressure builds. The Hawaiian islands are formed from volcanoes with non-viscous lava.
Why is Felsic magma explosive?
Felsic magma tends to have large amounts of gas, chiefly water vapor, carbon dioxide, and sulfur dioxide, trapped in it under pressure. When it gets near the surface the pressure drops. The gas is released and expands rapidly, creating an explosion. The effect is similar to opening a freshly shaken can of soda, only much more violent.
Temperature differences between acidic and basaltic lava?
Acid lava comes from composite cone volcanoes, is slow moving and viscous. Basic lava comes from shield volcanoes, is runny and flows faster. Acidic lava is felsic, or high in quartz and potassium feldspars. Basic lava is mafic, and higher in plagioclase feldspar.
Why is there no quartz formed in magma after it has cooled?
If you can't see its crystals without a microscope it's because the rock solidified too rapidly for visible crystals to form. Whether or not quartz is found in cooled magma/lava is basically a product of the chemical makeup of the molten rock. Quartz is the predominate silicate mineral in felsic igneous rocks, but may be non-existent in mafic igneous rocks. If you are referring to the fact that most felsic igneous rocks containing quartz do not exhibit well formed quartz crystals, it is because quartz is one of the last minerals to crystallize from magma, and solidifies in the voids between other minerals that have already crystallized.
