Basaltic magmas are associated with fissure eruptions creating lava flows spilling out from cracks in the crust. This is because basaltic magmas are more viscous and contain a lower concentration of gases than rhyolitic magma and therefore are unable to build up sufficient pressure to produce explosive eruptions.
Composite volcanoes typically have andesitic magma, which is intermediate in composition between felsic and mafic magmas. This type of magma is more viscous than mafic magma, leading to explosive eruptions and the buildup of lava and ash layers that form the characteristic steep-sided cone shape of composite volcanoes.
Like most cinder cones Paricutin was fed by mafic magma.
Mafic magma has low silica content. It is usually rich in magnesium and iron, leading to its high density and fluid-like behavior. Mafic magmas tend to form basaltic rocks when they solidify.
Mafic lava is less viscous(runnier) than felsic lava due to a lower silica content. This causes non-violent eruptions such as in the Hawaiian Islands. Mafic lava tends to be associated more with interplate volcanism and mid-ocean ridges and produces the rock type known as basalt. (The ocean floor is made of basalt.) Felsic lava is mainly found at convergent zones (areas of colliding plates) and has a high silica and water content which causes the lava to be highly viscous and causes very violent eruptions. This lava produces rhyolite and andesitic rocks. The color of the rocks formed by magmas is a consequence of its composition, mafic magmas are dark colored (Mg-Fe) and felsic magmas are light colored (Feldspars-Si).
Krakatoa volcano typically has mafic magma, which is low in silica content and high in magnesium and iron. This type of magma tends to be more fluid and can lead to explosive eruptions due to the rapid release of gases.
Composite volcanoes typically have andesitic magma, which is intermediate in composition between felsic and mafic magmas. This type of magma is more viscous than mafic magma, leading to explosive eruptions and the buildup of lava and ash layers that form the characteristic steep-sided cone shape of composite volcanoes.
Like most cinder cones Paricutin was fed by mafic magma.
Mafic magma has low silica content. It is usually rich in magnesium and iron, leading to its high density and fluid-like behavior. Mafic magmas tend to form basaltic rocks when they solidify.
Mafic lava is less viscous(runnier) than felsic lava due to a lower silica content. This causes non-violent eruptions such as in the Hawaiian Islands. Mafic lava tends to be associated more with interplate volcanism and mid-ocean ridges and produces the rock type known as basalt. (The ocean floor is made of basalt.) Felsic lava is mainly found at convergent zones (areas of colliding plates) and has a high silica and water content which causes the lava to be highly viscous and causes very violent eruptions. This lava produces rhyolite and andesitic rocks. The color of the rocks formed by magmas is a consequence of its composition, mafic magmas are dark colored (Mg-Fe) and felsic magmas are light colored (Feldspars-Si).
Krakatoa volcano typically has mafic magma, which is low in silica content and high in magnesium and iron. This type of magma tends to be more fluid and can lead to explosive eruptions due to the rapid release of gases.
High silica magmas can explode violently as its high viscosity causes a greater build up of pressure inside the volcano. Magmas low in silica tend to produce volcanic eruptions that are runny because of low viscosity.
Explosive
Plinian eruptions are caused by highly viscous magma with high eruptive column heights, explosive fragmentation of magma, and high gas content, often derived from silica-rich (silicic) magma. This type of magma tends to trap gases leading to highly explosive eruptions characteristic of Plinian events.
Gabbro is a type of mafic phaneritic rock. It is composed mainly of pyroxene, plagioclase feldspar, and often contains minor amounts of amphibole, olivine, or biotite. Gabbro forms from the slow crystallization of mafic magma deep within the Earth's crust.
Eyjafjallajökull volcano in Iceland produces andesitic magma, which is a type of intermediate magma that has a silica content between basaltic and rhyolitic magmas. This type of magma can lead to explosive eruptions due to its high viscosity, gas content, and tendency to form pyroclastic flows.
The relationship between silica content and water content in magma significantly influences the type of volcano formed. Magmas with high silica and water content tend to produce explosive, stratovolcanoes, as their viscosity traps gases, leading to violent eruptions. Conversely, low-silica, low-water magmas result in less viscous flows, creating shield volcanoes that produce gentle eruptions. This relationship emphasizes the role of magma composition in determining volcanic behavior and morphology.
Peridotite, a type of ultramafic rock composed largely of the mineral olivine, has the least silica.Read more: Which_igneous_rock_out_of_granite_basalt_andesite_and_peridotite_has_the_lowest_silica_SiO2_content