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Mafic and felsic are descriptive terms used in the classification of igneous rocks (those formed from molten materials, such as lava). Mafic rocks, such as basalt, are those that are high in dark-colored minerals composed mainly of magnesium and iron.
Apr 24, 2024 · As has already been described, igneous rocks are classified into four categories: felsic, intermediate, mafic, and ultramafic, based on either their chemistry or their mineral composition. The diagram in Figure 3.4.1 3.4. 1 can be used to help classify igneous rocks by their mineral composition.
Feb 19, 2024 · In geology, these terms are descriptive of the chemicals that make up igneous rocks, magmas, and silicate minerals. “Mafic” is a term that describes igneous rocks or silicate material characterized by a rich content of iron and magnesium while felsic rocks are igneous rocks that are rich in light elements such as oxygen, aluminum, silicon ...
Felsic igneous rocks, as a whole rock, tend to have light colors or shades: white, pink, light brown, light gray. Mafic igneous rocks, on the whole, tend to be dark colored, commonly black or dark gray. Most mafic magma originates by melting of rocks in the mantle that are extremely rich in iron and magnesium. Felsic magma usually originates in ...
Dec 10, 2023 · Felsic rocks are silica-rich rocks high in minerals like quartz, feldspars, or muscovite and relatively low iron and magnesium minerals. Usually, rocks classified as felsic have at least 75% felsic minerals. These minerals are orthoclase, quartz, and plagioclase. Those with more than 90% are leucocratic. Felsic rocks are usually light-colored.
Many parallel mafic and felsic bands are present in this area. The flattening of the fragments in the mafic bands suggests that this exposure is in the hinge of a fold. West of the lake, a large outcrop was investigated (Figure 4.17); it is a fine-grained, massive, featureless white felsic rock with 1-mm clear-quartz eyes. A combination of ...
The most common felsic rock is granite, which represents the purified end product of the earth's internal differentiation process. It is important to note that there are many intermediate steps in the purification process, and many intermediate magmas which are produced during the conversion from mafic to felsic.
