What is the Difference Between Mafic and Felsic?

Mafic and felsic are terms used to describe the chemical composition of silicate minerals, magmas, and igneous rocks. The main differences between mafic and felsic rocks are their silica content, color, and mineral composition:

1. Silica Content: Felsic rocks are high in silica (SiO2), while mafic rocks are low in silica. In a widely accepted silica-content classification scheme, rocks with more than 65% silica are called felsic, and those with between 45% and 55% silica are mafic.
2. Color: Mafic rocks are dark in color, while felsic rocks are light in color. The dark color of mafic rocks is due to the presence of magnesium and iron, while felsic rocks are lighter in color due to the predominance of lighter elements like silicon, oxygen, aluminum, sodium, and potassium.
3. Mineral Composition: Mafic rocks are typically composed of minerals such as olivine, pyroxene, amphibole, biotite mica, and plagioclase feldspars. In contrast, felsic rocks are high in light-colored minerals, including feldspar and quartz.

Examples of mafic rocks include basalt and gabbro, while examples of felsic rocks include granite and rhyolite. Mafic magmas are more dense and less viscous than felsic magmas, so they rise more quickly through the Earth's crust. Mafic rocks are usually found at spreading centers, while felsic rocks are typically associated with convergent zones.

Comparative Table: Mafic vs Felsic

Mafic and felsic are terms used to describe igneous rocks based on their mineral composition and silica content. The main differences between mafic and felsic rocks are as follows:

Mafic rocks are rich in iron and magnesium, and they are darker and denser than felsic rocks. On the other hand, felsic rocks are rich in silica and aluminum, and they are lighter and have a higher silica content than mafic rocks.