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They are descriptive terms as to the relative silica content of igneous rocks. Igneous rock which is high in silica is referred to as felsic. Igneous rock which is relatively low in silica is referred to as mafic.

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Mafic and felsic are terms used to describe the composition of igneous rocks.

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Q: What are the terms felsic and mafic used by geologists to describe?
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Is sandstone felsic or mafic?

Neither. The terms mafic and felsic refer to the composition of igneous rocks, which are dominated by silicate minerals. Marble is a metamorphic rock composed of carbonate minerals. The terms mafic and felsic do no apply to it.


Is rock salt felsic or mafic?

Neither. The terms mafic and felsic refer to the composition of igneous rocks, which are dominated by silicate minerals. Rock salt is a sedimentary halide rock. Such terms do not apply to it.


Is Tuff mafic or 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.


Are mafic rocks solely intrusive or extrusive?

No. The terms felsic and mafic refers to the relative content of certain minerals in the magma or rock. A mafic rock can be extrusive like basalt, or intrusive like gabbro. Basalt and gabbro can be identical in chemical composition.


What is the pH of andesite?

Andesite does not have pH. pH is a measure of how acidic or basic an aqueous solution is, meaning a solution in which the solvent is water. Andesite is a rock, not an aqueous solution. The terms "acidic" and "basic" were once used by scientists to describe the composition of igneous rocks, but this was based on an incorrect interpretation of their chemistry. These terms were replaced with felsic and mafic respectively. In either case, andesite is considered intermediate.

Related questions

Is sandstone felsic or mafic?

Neither. The terms mafic and felsic refer to the composition of igneous rocks, which are dominated by silicate minerals. Marble is a metamorphic rock composed of carbonate minerals. The terms mafic and felsic do no apply to it.


Is a limestone mafic?

No. The terms mafic and felsic apply to igneous rocks. Limestone is a sedimentary/biochemical rock and so cannot be said to be mafic, felsic, or intermediate.


Is coal mafic or felsic?

It is neither mafic or felsic, as these terms refer to the composition of igneous rocks, whereas coal is a sedimentary rock.


Is rock salt felsic or mafic?

Neither. The terms mafic and felsic refer to the composition of igneous rocks, which are dominated by silicate minerals. Rock salt is a sedimentary halide rock. Such terms do not apply to it.


Coal felsic or mafic?

Neither. The terms mafic and felsic apply to silicate igenous rocks. Coal is neither igneous nor is it composed of silicates. Coal is an organic sedimentary rock.


Are all rocks either mafic or felsic?

No. First of all, the terms mafic and felsic generally only apply to igneous rock. even among igneous rocks, mafic and felsic are just ranges on a "spectrum" of composition. Other classifications and examples include ultramafic (peridotite), intermediate (andesite), and intermediate-felsic (dacite).


Is a marble rock ultramafic?

No. Mafic, felsic, and related terms apply to silicate igneous rocks. Marble is composed of carbonates, so such terms do not apply.


Is Tuff mafic or 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.


Are mafic rocks solely intrusive or extrusive?

No. The terms felsic and mafic refers to the relative content of certain minerals in the magma or rock. A mafic rock can be extrusive like basalt, or intrusive like gabbro. Basalt and gabbro can be identical in chemical composition.


What is the pH of andesite?

Andesite does not have pH. pH is a measure of how acidic or basic an aqueous solution is, meaning a solution in which the solvent is water. Andesite is a rock, not an aqueous solution. The terms "acidic" and "basic" were once used by scientists to describe the composition of igneous rocks, but this was based on an incorrect interpretation of their chemistry. These terms were replaced with felsic and mafic respectively. In either case, andesite is considered intermediate.


What are two types of magma?

The three types of magma are basalt, andesite, and rhyolite. Basalt is flowing and is usually around 1,200 degrees Celsius. Andesite is flowing and explosive and is usually between 800 to 1,000 degrees C. Rhyloite is very explosive and is usually at 750 to 850 degrees Celsius.


Which of the following terms does NOT describe a form of a fat?

Which of the following terms does NOT describe a form of a fat?Cholesterol