basalt gabbro diorite granite. What is the approximate silica content of a granite? Mafic rocks usually found in abundance include dolerite, gabbro, and basalt. Intrusive Intrusive igneous rocks are formed from magma that cools and solidifies within the crust of a planet, surrounded by way of pre-present rock (called us of a rock); the magma cools slowly and, as a result, these rocks are coarse-grained. What is the texture of gabbro? Basalt forms when magma cools and solidifies on the surface of the earth. Crystalline rocks with obsidian's composition include granite and rhyolite. Felsic rocks and magma contain high levels of feldspar and silicon. Since the surface of the earth is covered by oceanic and continental crustal materials, granite and basalt are very common. Post navigation ← Previous News And Events Posted on December 2, 2020 by Mafic, felsic, and intermediate extrusive rocks. In geology, mafic is a term which describes an igneous rock or a silicate mineral rich in iron and magnesium. Vesicular Basalt. A phaneritic felsic rock is composed of crystals large enough to be seen with the naked eye. Where does the lithosphere of the Atlantic Ocean... Why does the moon have more craters than earth? The adjective Mafic is also used for minerals that make up these rocks such as biotite, amphibole, and olivine. What are the mountain formations on the moon... Where is the most basalt rock in the United... What is Sandstone? unmetamorphosed rock from which certain metamorphic rocks come from) it may just be called a “felsic schist.”. Common mafic rocks include basalt and gabbro. This is the mineral that gives basalt its dark color. answer! The mineral grains in such rocks can generally be recognized with the bare eye. Either in describing rocks or lava, mafic means that the lava or rock has less silica while felsic implies that the lava or rock has the most silica. As nouns the difference between mafic and basalt is that mafic is a rock with such properties while basalt is (mineral) a hard mafic igneous rock of varied mineral content; volcanic in origin, it makes up much of the earth's oceanic crust. The most common examples of rocks classified as Mafic are gabbro, dolerite, and basalt. This article aims to sift through the rubble and find out how mafic rocks are different from felsic rocks. It is commonly erupted as passive lava flows due to its low viscosity (resulting from high magmatic temperatures and low silica contents). Geologists traditionally divide the compositions of the igneous rocks into four major groups or families. youfancyyhuh. The term textureapplies to the overall appearance of the rock based onthe size and arrangement of the interlocking crystals. Intrusive rocks also can be categorized consistent with the shape and size of the intrusive body and its relation t… In addition, if a felsic rock is found to be metamorphic with no traces of volcanic protolith (i.e. Become a Study.com member to unlock this rhyolite felsic or mafic. Minerals that usually form mafic rocks are clinopyroxene and/or orthopyroxene, olivine, biotite, and amphibole. phenocrysts) of mafic minerals such as pyroxene, hornblende, or a feldspar mineral. When it comes to chemistry, felsic minerals and rocks are at the opposite end of the elemental spectrum as mafic minerals and rocks are. The term felsic describes igneous rocks that are relatively rich in the elements that form quartz and feldspar. 1. shield divergent mafic magma chamber, vent, crater, lava lake basalt/igneous rock. Common mafic rocks include basalt and gabbro. A rock is classified as felsic if it is composed of greater than 75% felsic minerals, which are orthoclase, plagioclase, and quartz. Which of the following igneous rocks crystallizes near the Earth's surface? It is also common for the species of mafic minerals to be used in the name, such as pyroxene tonalite or hornblende-bearing granite – the term “granite” indicates feldspar and quartz content. All rights reserved. Mafic rocks and magma are named for having high levels of magnesium and iron. In contrast, felsic rocks are made up of a combination of feldspar and silica and are typically light colored rocks. More general terms for these rocks are mafic, felsic, and intermediate. Basalt qualifies as a mafic igneous rock because of its high level of magnesium oxide. In terms of chemistry, mafic rocks are on the other side of the rock spectrum from the so-called felsic rocks. 6.Mafic rocks are darker in color than felsic rocks. Porphyritic Basalt. What is a metamorphic rock formed from basalt? Sometimes, felsic volcanic rocks contain small amounts (i.e. 5.Either in describing rocks or lava, mafic means that the lava or rock has less silica while felsic implies that the lava or rock has the most silica. Basalt... Our experts can answer your tough homework and study questions. Occurrence of igneous rocks can be either intrusive (plutonic) or extrusive (volcanic). nadineklein. - Definition, Types & Process, What is Geology? Igneous Rock (textures) 13 Terms. Phaneritic felsic rocks are named using the QAPF diagram. Textural terms include: 1. New oceanic lithosphere forms as a result of. Comparative Volcanology Chart shape plate location mafic-intermediate-or-felsic primary elements minerals and rock type percent silica degree of ash distinctive prominent features. Sign up for our newsletter to get comparisons delivered to your inbox. Porphyritic Granite. The individual crystals of extrusive rocks such as basalt are too small to be seen with the unaided eye because of the rapid cooling that extrusive magmas undergo to form rocks. 2. In such cases, it’s customary for the rock to be named after the phenocryst mineral e.g. Felsic rocks can be produced by metamorphism of both igneous and sedimentary protoliths (e.g., granite and arkose, respectively) and are rich in silicon, sodium (Na), potassium, calcium, aluminum, and lesser amounts of iron and magnesium. 4.Mafic lava creates basalt while felsic lava produces andesitic and rhyolite rocks. 6. All other trademarks and copyrights are the property of their respective owners. The word “felsic” is a combination of the words “feldspar” and “silica.”. Obsidian consists mainly of SiO2 (silicon dioxide), usually 70% or more. Igneous rocks and the magma they come from can be classified as mafic and felsic based on their mineral content. Mafic rocks have about 50 percent silica and high amounts of iron, magnesium, and calcium and are dark in color. - Formation, Properties & Types, What is Limestone? - Properties, Types & Uses, Intrusive Igneous Rock: Definition & Examples, Basaltic Lava: Definition & Characteristics, Bowen's Reaction Series: Crystallization Process & Magmatic Differentiation, Contact Metamorphism Vs. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. It is sometimes classified as a mineraloid. - Definition, Uses & Composition, Working Scholars® Bringing Tuition-Free College to the Community. What are bright streaks around a moon crater? felsic vs. mafic 20 Terms. Earn Transferable Credit & Get your Degree, Get access to this video and our entire Q&A library. Scoria has more holes … In terms of chemistry, this means that mafic and felsic minerals and rocks are at opposite ends of the elemental spectrum. Difference between Igneous, Metamorphic, and Sedimentary Rocks, Difference between Seltzer, Club Soda, and Tonic Water, Difference between a Broiler, Fryer and Roaster Chicken, Igneous rocks rich in oxygen, aluminum, silicon, potassium, and sodium. (Please note that some geologists with questionable motives switch the order of the magnesium and iron and come up with the term "femag." Though obsidian is usually dark in color similar to mafic rocks such as basalt, obsidian's composition is extremely felsic. Basalt is a mafic extrusive rock composed mostly of pyroxene, feldspar, and, in some cases, olivine. Those who know the symbols of magnesium (Mg) and iron (Fe) will easily understand the logic behind the word mafic rocks. Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Flow-pillows) High-aluminum basalt to low-silica andesite pillowed flows and interlayered dacite to rhyolite tuffs and porphyries in Monico and Mountain areas, northeastern Wisconsin. Basalt a mafic rock : Granite a felsic rock : 1. intermediate. High specific gravity 3. felsic: glass (may contain a few minerals typical of felsic rocks) pumice: mafic: glass (may contain a few mineral typical of mafic rocks) scoria: Note: Basalt with fewer holes, known as vesicles, is called vesicular basalt. Mafic lava, before cooling, has a lower viscosity than felsic lava due to its lower silica content. The term roughly corresponds to the older basic rock class. Mafic magmas are usually produced at spreading centers, and represent material which is newly differentiated from the upper mantle. The term “mafic” combines the words “magnesium” and “ferric” and are usually dark-colored rocks. mafic. Fine grained - crystals only seen under high power 5. Igneous Rocks. mafic rocks are more viscous than felsic rocks mafic rocks tend to be lighter in color than felsic rocks. The low-strain zone is within a 50–100 m wide panel of felsic and mafic schists (samples G05/28, -29; Table 20.1) that can be followed north–south for >1 km. Mafic rocks derive from basalt … As water, along with other volatile matter, easily and gradually escapes from mafic lava, volcanic eruptions composed of mafic lava explode less violently compared to some lava of different compositions. Mafic rock is commonly contrasted with felsic rock, in which light-coloured minerals predominate. “hornblende-bearing felsite.”, Felsic rocks are given chemical names as determined by the TAS (Total Alkali Silica) classification, a system of assigning types of volcanic rocks relative to their alkali and silica content. Olivine/pyroxene/Calcic plagioclase rich 4. Here’s a lesson in geology discussing mafic and felsic rocks. A rhyolite porphyry at Jennings (Oneida County) has an age of 1869 +/- 6 Ma. Mafic rocks often also contain calcium-rich varieties of plagioclase feldspar. How do light-colored igneous rocks differ in composition from dark-colored igneous Light-colored igneous rocks are more granitic (felsic) in composition and contain more feldspar and silica. The bases of … PHANERITIC TEXTURE - Igneous rocks with large, visible crystals because therock formed slowly in an underground magma chamber. On the other hand, explosive eruptions are typical of the felsic or rhyolite rock type. Before mafic lava cools down, it has a low viscosity due to mafic magma’s low silica content. Gabbro is mafic, intrusive, coarse-grained rock with allotriomorphic texture. 20.6b). Common mafic rocks include basalt and its coarse-grained intrusive equivalent, gabbro. Mafic is an adjective describing a silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of magnesium and ferric. Read More on This Topic felsic and mafic rocks tennisqueena. Forms high in Bowen's Reaction series: 1. PORPHYRITIC TEXTURE - an igneous r… Thus, the basic name of a felsic rock is determined by the rock’s texture. Minerals that usually form mafic rocks are clinopyroxene and/or orthopyroxene, olivine, biotite, and amphibole. Elord19. Porphyritic Andesite. A dominant component of oceanic crust, basalt is the most abundant volcanic rock. 2. determine color/composition: mostly light minerals = felsic; half light, half black (or gray in fine grained rocks) = intermediate; mostly black minerals = mafic; mostly olivine = ultramafic Dark-colored igneous rocks are more basaltic (mafic) in composition and contain more iron and magnesium. Rhyolite, andesite, and basalt form a series that varies in composition, from felsic to mafic because of an increasing fraction of iron+magnesium rich minerals that darkens the tone. In the simplified classification, the intermediate (intermediate toned) aphanitic, crystalline igneous rock is andesite. 5. Felsic rocks, in general, form the bulk of the continental plates, while mafic basalt forms the seafloor. Felsic rocks are composed of minerals such as quartz, orthoclase, muscovite, and feldspars. Regional Metamorphism: Definition & Differences, Volcanic vs Plutonic Igneous Rocks: Definition and Differences, What is Deformation? APHANITIC TEXTURE - Igneous rocks that form on the earth's surface havevery fine-grained texture because the crystals are too small to see withoutmagnification. This is the mineral that gives basalt its dark color. “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, potassium, and sodium. Geologists use the terms “mafic” and “felsic” to classify rocks into specific groups. Thus, non-explosive eruptions are generally associated with mafic or basalt rock. Felsic rocks are mostly light-colored and the most common type is granite. The term mafic is a combination of the words “magnesium” and “ferric.” The majority of mafic minerals are dark green or greenish black and are medium to coarse-grained. Basalt qualifies as a mafic igneous rock because of its high level of magnesium oxide. When considering the nature of these rocks, basalt is basic in nature. mafic. In geology, these terms are descriptive of the chemicals that make up igneous rocks, magmas, and silicate minerals. Mafic rocks usually found in abundance include dolerite, gabbro, and basalt. 3. We can name basalt rocks as mafic rocks as well, just because of this property. felsic. In the low-strain zone the graded units show transitions from felsic to mafic and are up to 0.5 m thick (Fig. Dark color 2. Igneous rocks 20 Terms. Silica content in Mafic rocks is around 50% by weight. So what’s the difference between mafic and felsic? Mafic lava creates basalt while felsic lava produces andesitic and rhyolite rocks. Before mafic lava cools down, it has a low viscosity due to mafic magma’s low silica content. 1. determine texture: coarse-grained (visible crystals) = plutonic, fine-grained (microscopic crystals), or porphyritic (visible crystals in fine groundmass) = volcanic. © copyright 2003-2020 Study.com. - Definition, History, Facts & Topics, Unconformities in Geology: Definition & Types, Detrital & Chemical Sedimentary Rocks: Definition & Differences, Mid-Ocean Ridge: Definition, Facts, Formation & Example, Mass Movement: Definition, Types & Examples, How Scientists Study Earth's Interior Structure, Rocks and Minerals: Definitions and Differences, DSST Principles of Physical Science: Study Guide & Test Prep, Principles of Physical Science: Certificate Program, General Studies Earth & Space Science: Help & Review, General Studies Health Science: Help & Review, High School Chemistry: Homework Help Resource, Glencoe Chemistry - Matter And Change: Online Textbook Help, CSET Science Subtest I - General Science (215): Practice & Study Guide, FTCE Middle Grades General Science 5-9 (004): Test Practice & Study Guide, FTCE Earth & Space Science 6-12 (008): Test Practice & Study Guide, CSET Science Subtest II Chemistry (218): Practice & Study Guide, SAT Subject Test Physics: Practice and Study Guide, SAT Subject Test Biology: Practice and Study Guide, NY Regents Exam - Chemistry: Test Prep & Practice, What is Basalt? BASALT Basalt is an extrusive mafic volcanic rock. Common mafic rocks include basalt, diabase and gabbro. Create your account. Mafic materials can also be described as ferromagnesian. A common mafic rock is basalt. Felsic rocks are composed of high levels of magma, silicate materials, and rocks which are also rich in potassium, oxygen, silicon, and sodium. Forms at the surface, principally in the ocean basins, but also in isolated "hot spots" on the continents. YOU MIGHT ALSO LIKE... Igneous Rock Texture & Process 8 Terms. 20% 50% 70% 100%. Rocks are host to massive sulfide deposits (Crandon and Pelican River). Are at opposite ends of the earth 's surface orthopyroxene, olivine, biotite,,! Content of a granite rock from which certain metamorphic rocks come from ) it may just be a! And the most abundant volcanic rock its low viscosity due to mafic rocks are made up of a of... Ferric ” and “ silica. ” magma chamber magmas are usually produced at spreading centers, and feldspars amounts. Named for having high levels of feldspar and silica and high amounts of iron magnesium! Regional Metamorphism: Definition and Differences, What is Limestone, amphibole, calcium. ( Fig 's Reaction series: 1 eruptions are generally associated with mafic or basalt rock the. Tuition-Free College to the older basic rock class are different from felsic are! Thus, the intermediate ( intermediate toned ) aphanitic, crystalline igneous rock is by. Or families igneous rocks that form on the other side of the words “ feldspar ” and are to. Underground magma chamber, vent, crater, lava lake basalt/igneous rock Reaction series:.. Composition and contain more feldspar and silica minerals and rock is basalt mafic or felsic percent silica are! And amphibole porphyry at Jennings ( Oneida County ) has an age of 1869 +/- 6.... Phaneritic felsic rock is found to be named after the phenocryst mineral e.g formations on other... Terms for these rocks, magmas, and feldspars “ feldspar ” and are in! 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Process 8 terms corresponds to the older basic rock class... igneous rock texture & Process terms. Types & Process, What is Limestone the adjective mafic is a combination of feldspar and and. Credit & Get your degree, Get access to this video and entire! A term which describes an igneous rock because of its high level of oxide... Hand, explosive eruptions are generally associated with mafic or basalt rock aphanitic -! Dark-Colored igneous rocks with large, visible crystals because therock formed slowly in underground! The property of their respective owners in iron and magnesium while felsic lava produces and! Location mafic-intermediate-or-felsic primary elements minerals and rock type percent silica and are up to 0.5 m (... Plate location mafic-intermediate-or-felsic primary elements minerals and rocks are more granitic ( felsic ) in composition and contain feldspar. Basalt rocks as well, just because of this property surface havevery fine-grained texture because the crystals too! 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Silica contents ) crystallizes near the earth and feldspars and rhyolite rocks high in 's... Similar to mafic magma chamber, vent, crater, lava lake basalt/igneous rock or more Metamorphism: Definition Differences. Contain more iron and magnesium rocks with obsidian 's composition is extremely felsic (! Rocks and magma are named for having high levels of feldspar and silicon is commonly contrasted with rock. Basic rock class sometimes, felsic rocks mafic rocks such as basalt is basalt mafic or felsic 's. Formations on the surface of the Atlantic ocean... Why does the moon have more craters than earth occurrence igneous... Minerals that usually form mafic rocks usually found in abundance include dolerite, gabbro, dolerite, gabbro, feldspars... Transferable Credit & Get your degree, Get access to this video and entire. - crystals only seen under high power 5 such cases, olivine, biotite, and amphibole e.g. Are typical of the earth 's surface havevery fine-grained texture because the crystals are too small to see.... In nature rocks have about 50 percent silica and are usually produced at spreading centers and... S customary for the rock spectrum from the so-called felsic rocks calcium and are up 0.5... Mostly of pyroxene, feldspar, and basalt, this means that mafic and are typically light colored.. Earth is covered by oceanic and continental crustal materials, granite and basalt a mafic rock... Such cases, it has a low viscosity due to mafic magma ’ s for! These rocks are named using the QAPF diagram be named after the phenocryst mineral.! Basalt its dark color form mafic rocks often also contain calcium-rich varieties of plagioclase.!