Felsic magmas have higher silica content, making them more viscous and prone to trapping gas bubbles. When trapped gas pressure builds up, it can lead to a more explosive eruption. Mafic magmas, on the other hand, have lower silica content and are less viscous, allowing gas to escape more easily, resulting in less explosive eruptions.
Mafic magmas generally have lower viscosity and gas content compared to felsic magmas, so they tend to flow more easily rather than explode. However, in certain conditions where gas build-up is high and pressure is released rapidly, mafic magma may still explode, but it is less common than with felsic magmas.
Mafic lava is low in silica and high in iron and magnesium, which makes it less viscous and more fluid compared to felsic lava. It tends to flow easily and often forms basaltic rocks when it cools. Mafic lava eruptions typically result in gentle, effusive lava flows rather than explosive eruptions.
Rhyolite is not a mafic rock, but a felsic rock, high in silicates, and similar to granite in composition.
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.
Pumice is more related to a textural feature, rather than a compositional attribute. For example, pumice originates when there are enough dissolved gases in the magma, such that when it is ejected from the volcano, the depressurization of the dissolved gases causes a rapid expansion as the gases exsolve (just like when you open a pop - the gases are initially under pressure, and you release that pressure by opening the can or bottle). The rapid change in temperature, from hundreds to thousands of degrees to the temperature of of the surrounding environment, causes a rapid cooling effect, whereby the expanding gases are frozen in place. These two factors are what give pumice its distinctive texture and ability to float when placed in water, as opposed to other volcanic rocks (such as scoria).Whether or not the pumice is felsic (light in color) or mafic (dark in color) depends on its chemical composition and therefore, pumice can be both felsic or mafic depending on its parental magma.General classification as to whether a rock is felsic or mafic is with regards to the silicate content of the rock as follows:felsic < 69% SiO2Intermediate Felsic 63 - 69% SiO2Intermediate 52- 63% SiO2Mafic < 52% SiO2Ultra Mafic < SiO2This said, felsic pumice (white or light tan brown colors) are more common to find than mafic pumice.
Eruptions involcing silicic or felsic magma are generally the worst. Eruptions of mafic material are usually effusive or only mildly explosive, producing cinders or lava flows. Eruptions of felsic material often produce large ash clouds and deadly pyroclastic flows.
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.
Mafic magmas generally have lower viscosity and gas content compared to felsic magmas, so they tend to flow more easily rather than explode. However, in certain conditions where gas build-up is high and pressure is released rapidly, mafic magma may still explode, but it is less common than with felsic magmas.
Lava can be classified into two main types: mafic lava, which is rich in magnesium and iron and tends to flow easily, creating broad shield volcanoes, and felsic lava, which is high in silica and more viscous, leading to explosive eruptions and the formation of stratovolcanoes.
They can. Composite volcanoes vary in what they erupt. Many composite volcanoes are composed of a mixture of mafic, felsic, and intermediate rock. However, in most cases intermediated or felsic rock predominates.
Mafic lava is low in silica and high in iron and magnesium, which makes it less viscous and more fluid compared to felsic lava. It tends to flow easily and often forms basaltic rocks when it cools. Mafic lava eruptions typically result in gentle, effusive lava flows rather than explosive eruptions.
Rhyolite is not a mafic rock, but a felsic rock, high in silicates, and similar to granite in composition.
Mafic magma, which is low in silica content, has a lower viscosity, allowing gases to escape easily during an eruption, resulting in quiet flows. In contrast, felsic magma is high in silica, making it more viscous and trapping gases within. When pressure builds up in felsic magma, it can lead to explosive eruptions as the trapped gases are released violently. This fundamental difference in composition and viscosity accounts for the contrasting eruption styles.
The 1980 eruption of Mount St. Helens produced dacite, which has an intermediate-felsic composition.
Mauna Loa exhibits non-explosive eruptions (like many in the Hawaiian islands) in the form of low viscosity (more fluid) lava due to poor silica content.
Mafic magma is characterized by its high content of magnesium and iron, resulting in a darker color and higher density compared to felsic magma. It typically has a lower viscosity, allowing it to flow more easily, which often leads to less explosive volcanic eruptions. Mafic magma is commonly associated with divergent plate boundaries and hotspot volcanoes, producing basaltic lava flows. Additionally, it usually contains fewer silica and gas components than its felsic counterpart.
Mafic lava, before cooling, has a low viscosity, in comparison to felsic lava, due to the lower silica content in mafic magma. Water and other volatiles can more easily and gradually escape from mafic lava, so eruptions of volcanoes made of mafic lavas are less explosively violent than felsic lava eruptions. Most mafic lava volcanoes are oceanic volcanoes, like Hawaii.Felsic is a term used in geology to refer to silicate minerals, magmas, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. The term combines the words "feldspar" and "silica." Felsic minerals are usually light in color and have specific gravities less than 3. Common felsic minerals include quartz, muscovite, orthoclase, and the sodium-rich plagioclase feldspars. The most common felsic rock is granite. On the opposite side of the rock spectrum are the iron and magnesium-rich mafic and ultramafic minerals and rocks.There are a few means by which felsic magma can be generated from mafic magma. Felsic materials have lower melting points than mafic materials and so will tend to melt first during partial melting. This can shift composition to something more felsic. Another process is called fractional crystalization. Here, more mafic material crystallizes and settles out of a magma chamber, making the remaining molten material more felsic. Finally, as mafic magma moves though continental crust, which is generally felsic in composition, it incorporates some of the rock and becomes more felsic.