The explosive volcanic eruptions that produce rhyolite are also sources of obsidian. The link is therefore to German Feld, meaning "field".[2]. Quiz & Worksheet - What Are Bronchial Tubes? In order for a rock to be classified as felsic, it generally needs to contain more than 75% felsic minerals; namely quartz, orthoclase and plagioclase. Not sure what college you want to attend yet? Did you know… We have over 220 college Like more familiar kinds of glass, it's high in silica. 2. Intrusive igneous rocks crystallize below Earth's surface, and the slow cooling that occurs there allows large crystals to form. Igneous rocks are classified according to their mineral content: Ultramafic rocks are dominated by olivine and/or pyroxene. Mafic rocks have between 45 and 55% of silica, whereas felsic rocks have over 65% of silica, the highest of all types. In some cases, felsic volcanic rocks may contain phenocrysts of mafic minerals, usually hornblende, pyroxene or a feldspar mineral, and may need to be named after their phenocryst mineral, such as 'hornblende-bearing felsite'. Older, broader usage is now considered archaic. It is a borrowing of Feldspat. Common felsic minerals include quartz, muscovite, hornblende, orthoclase, and the sodium rich plagioclase feldspars. study Felsic rocks are generally rich in silicon and aluminum and contain only small amounts of magnesium and iron. You'll also take a quiz to test your understanding. How to Do Your Best on Every College Test. Get the unbiased info you need to find the right school. The word 'felsic' was made up from parts of those words. - Definition & Overview, What is Geology? Feldspar, one of the key components of felsic rock, which is the name for a group of aluminum silicate minerals containing the light metallic elements potassium, sodium, or calcium. Suzanne has taught college economics, geography, and statistics, and has master's degrees in agricultural economics and marine affairs (marine resource management). Image: Basalt, Granite Biotite Hornblende, Rhyolite, Gabbro, and Diorite succeed. What are Igneous Rocks? Mafic rocks are dominated by plagioclase and pyroxene (even if you can't see them with the naked eye) and smaller amounts of olivine. On the opposite side of the rock spectrum are the iron and magnesium rich mafic and ultramafic minerals and rocks. - Definition, Calculation & Examples, Mid-Atlantic Ridge: Definition & Explanation, Mountain: Definition, Formation, Characteristics & Examples, Phagocytosis: Definition, Process & Types, The Mississippi River: Facts, History & Location, Where Is the Redwood Forest? The mineral compositions of igneous rocks are usually described as being felsic, intermediate, mafic, or ultramafic (as examples, see Figure 4.7 and Figure 4.8). Rhyolite is a felsic rock that, like granite, is rich in silicate minerals. The intrusion of large bodies of granite—batholiths—is usually part of the origin of a mountain range. In Figure 8.2 are examples of igneous rocks that represent the mafic and felsic rock compositions (Figures 8.2A and 8.2C, respectively), as well as an intermediate rock type (Figure 8.2B). The chemical composition of igneous rock can be broken into four main types: felsic, intermediate, mafic and ultramafic. However, rhyolite is extrusive. Andesite and diorite likewise refer to extrusive and intrusive intermediate rocks (with dacite and granodiorite applying to those rocks with composition between felsic and intermediate). An example of a felsic rock is _____ granite _____ rocks are a combination of felsic and mafic rocks. Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Rocks with greater than 90% felsic minerals can also be called leucocratic, from the Greek words for white and dominance. Rocks with greater than 90% felsic minerals can also be called leucocratic, meaning 'light-coloured'.Template:Citation needed Felsite is a petrologic field term used to refer to very fine-grained or aphanitic, light-colored volcanicrocks which might be later reclassified after a more detailed microscopic or chemical analysis. credit by exam that is accepted by over 1,500 colleges and universities. Granite is the most common intrusive rock on the continents; gabbro is … In order for a rock to be classified as felsic, it generally needs to contain more than 75% felsic minerals; namely quartz, orthoclase and plagioclase. Felsic rocks are usually light in color and have specific gravities less than 3. Why or why not? Create your account. Geologists don't intend to be confusing by using so many terms, but rather the terms are used for different properties. - Definition & Explanation, What is a Map Key/Legend? Like more familiar kinds of glass, it's high in silica. just create an account. [1] It is contrasted with mafic rocks, which are relatively richer in magnesium and iron. Because they are made of lighter elements, they tend to be more buoyant than mafic rocks, which are rocks high in magnesium and iron, like basalt. Anyone can earn The word 'felsic' was made up from parts of those words. "Felsic" and "igneous" are overlapping categories: granite and rhyolite are examples of felsic igneous rocks. Common mafic rocks include basalt and its coarse-grained intrusive equivalent, gabbro. Once you have determined the texture and composition of an igneous rock, you can name it and you can also say something important about how it formed. 1. Examples of felsic igneous rocks are granite, rhyolite, and pumice. Compilations of many rock analyses show that rhyolite and granite are felsic, with an average silica content of about 72 percent; syenite, diorite, and monzonite are intermediate, with an average silica content of 59 percent; gabbro and basalt are mafic, with an average silica content of 48 percent; and peridotite is an ultramafic rock, with an average of 41 percent silica. High specific gravity 3. 6. Regional Metamorphism: Definition & Differences, Non-silicate Minerals: Chemical Classifications & Examples, Comparing Silicate & Non-silicate Minerals, Volcanic vs Plutonic Igneous Rocks: Definition and Differences, Lithification of Sediments: Definition & Processes, Basaltic Lava: Definition & Characteristics, Optical Properties of Minerals: Luster, Light Transmission, Color & Streak, Geological Faults: Definition, Causes & Types, Silicate Minerals: Chemical Classifications & Examples, Transform Fault: Definition & Characteristics, Unconformities in Geology: Definition & Types, Holt McDougal Modern Chemistry: Online Textbook Help, High School Physical Science: Homework Help Resource, Holt McDougal Physics: Online Textbook Help, High School Biology: Homework Help Resource, DSST Environmental Science: Study Guide & Test Prep, UExcel Microbiology: Study Guide & Test Prep, Prentice Hall Biology: Online Textbook Help, Holt Physical Science: Online Textbook Help, Holt McDougal Modern Biology: Online Textbook Help, AP Environmental Science: Help and Review. The chemical name of a felsic rock is given according to the TAS classification of Le Maitre (1975). Igneous rocks are formed from the solidification of molten rock material. In this lesson, you will read about felsic rocks and find out what they're made of - their name gives clues to their composition. diorite. Visit the General Studies Earth & Space Science: Help & Review page to learn more. Obsidian fractures into very sharp-edged pieces, and cultures around the world have taken advantage of this fact to make beautiful cutting tools and weapons. {{courseNav.course.topics.length}} chapters | Unlike mafic rocks, which are rocks high in magnesium and iron (like basalt), felsic rocks come in amazing and unforgettable varieties. You can test out of the