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Does the lava that forms shield volcanoes probably have a lot of silica or water in it?
No. Shield volcanoes form from basaltic lava with a low silica content and a low water content.
How many shield volcanoes exist?
a lot
What are the characteristics of composite volcanoes?
they are very tall and steep, explosive, have a lot of silica, create landslides, pyroclastic flows, and lahars, cover the sky with ash, and are found mostly on continental plates because of the silica content.
What type of magma containing a lot silica and water vapor?
Felsic magma
Type of magma containing a lot of silica and water vapor?
Felsic magma.
Does the lava that forms shield volcanoes probably have a lot of silica or water in it?
No. Shield volcanoes form from basaltic lava with a low silica content and a low water content.
How many shield volcanoes exist?
a lot
How are composite volcanoes and shield volcanoes different?
Composite volcanoes or Stratovolcanoes are your typical cartoon image of volcanoes, very tall, narrow craters at the top, steeper sides often snow capped peaks. Shield volcanoes tend to not be as tall and have much more shallow sloping sides. The reason for this is due to their products and location. Composite volcanoes produce lava which is much more viscous (thicker) than shield volcanoes, which tend to produce a thinner runnier lava. This is due to the Silica (SiO2) content of the lavas. Composite volcanoes tend to be produced by more Acidic lavas (with a higher Silica content) where as shield volcanoes are produced by lavas with a more Basic composition, (a lower silica content). Composite volcanoes (Mt St Helens, Vesuvius, Mt Fugi) tend to be formed near destructive plate boundries where one tectonic plate is being subducted beneath another. When the subducted plate reaches roughly 700 km depth it begins to enter the Aesthenosphere, a layer of more ductile rock deep in the mantle. The water content of the subducted plate causes the aesthenosphere to partially melt. The molten magma begins to rise in plumes towards the surface. As the magma plume rises it has a lot of contact with the surrounding rocks it passes through, and it absorbs silica from them, arriving at the surface as a viscous silica rich melt. Shield volcanoes (Mauna Loa, Kiluea, Hekla) are more common over constructive plate margins where two plates are pulling apart. When the plates pull apart it de-pressurises the mantle beneath the plates and causes it to partially melt. The Magma rises up the cracks between the two retreating plates, with little contact to the surrounding rocks, and so picks up very little silica content. This causes it to reach the surface as a runny basic lava. The runny nature of shield volcanoes means that lava flows travel a long way from the volcano crater, causing little build up on the surrounding flanks of the volcano. The viscous nature of Composite volcanoes means that the lava doesn't travel very far and builds up on the sides of the volcanoes making them much steeper. Shield volcanoes are more often active than composite volcanoes, some erupt near constantly for many decades. Composite volcanoes erupt far less often, and can be mistakenly thought of as being extint for hundreds of years between eruptions. Composite volcanoes tend to have much more explosive eruptions than shield volcanoes, which tend to be more effusive in nature. Composite volcanoes are capable of pyroclastic flows (Mt St Helens) and huge eruptions which can entirely destroy the volcano (Pinatubo, Krakatoa). Shield volcanoes tend to only erupt in lava flows, which can create enormous shallow volcanoes (Mauna Loa, Olympus Mons)
If a tall shield volcano has been built by many eruptions over thousands of years the magma that helped build the volcano contained?
a lot of silica and only a little water vapor
What are the characteristics of volcanoes?
they are very tall and steep, explosive, have a lot of silica, create landslides, pyroclastic flows, and lahars, cover the sky with ash, and are found mostly on continental plates because of the silica content.
What are the characteristics of composite volcanoes?
they are very tall and steep, explosive, have a lot of silica, create landslides, pyroclastic flows, and lahars, cover the sky with ash, and are found mostly on continental plates because of the silica content.
What type of magma containing a lot silica and water vapor?
Felsic magma
Type of magma containing a lot of silica and water vapor?
Felsic magma.
What is the type of magma contain a lot of silica and water vapor is?
The three types of magma, named for the rock they form are basaltic, rhyolitic and andesitic. Rhyolitic magma is rich in silica and water vapor.
Does AA lava have a lot of silica?
no. AA has a relatively low silica content level.
Did Pliny write a lot about volcanoes?
Yes!Pliny write a lot about volcanoes.
How does silica affect a volcano eruption?
The higher the silica content of the magma, the more viscous the magma. The higher the viscosity of the magma, the more explosive the eruptions of the volcano tend to be. Lower silica content lavas tend to form shield volcanoes (such as the type formed on Hawaii) where the lava can flow very long distances as it has a much lower viscosity.
