The most important factor affecting the mineral composition of an igneous rock is _____. Diorite is the name given to intrusive intermediate rocks, whereas andesite is the name given to extrusive intermediate rocks. Wiley-Blackwell. FALSE: Mafic rocks are denser than felsic rocks BECAUSE: mafic rocks are made of more Fe and Mg which are denser elements. Mafic Rock. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous.. Tuff is a relatively soft rock, so it has been used for construction since ancient times. • I can describe how mafic magma differs from felsic magma. Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. Granite would have more SiO2 (silica, quartz) than Gabbro. 15% 45% 85% 5% 30% 60% 95% Figure A5.5.1 The mafic minerals in photo A are shown as black areas in map B. Uralite is a name given to secondary hornblende (or actinolite) phenocrysts. Subsequently, one may also ask, is granite mafic felsic or intermediate? Felsic rocks are light in color and are composed of feldspars and silicates. PHANERITIC TEXTURE - Igneous rocks with large, visible crystals because therock formed slowly in an underground magma chamber. Diorite (red) on the QAPF diagram. It is used as a dimension and building stone, but not very widely because of limited supply. This makes it difficult to carve and work with, but also allows it to be worked finely and take a high polish, and to provide a durable finished work. schist - metamorphic rock that cannot fall into these categories . Is rhyolite felsic or mafic or intermediate? West of the lake, a large outcrop was investigated ( Figure 4.17 ); it is a fine-grained, massive, featureless white felsic rock with … Its vesicular structure makes it light enough to float on water. Being of intermediate composition between felsic and mafic, diorite is classically a salt and pepper rock made largely of white to light gray plagioclase and black hornblende. Intrusive Igneous Rocks 2. Diorite has a phaneritic, often speckled, texture of coarse grain size and is occasionally porphyritic.  Minor amounts of muscovite may also be present. These rocks (basalt, gabbro) are usually dark coloured, and have a higher density than felsic … Intermediate magmas are somewhat more viscous than the mafic magmas. Kaatiala, Finland. mafic 96: - Based on your estimate, describe this rock as felsic, intermediate, mafic, or ultramafic. It sits in the middle of mafic gabbro and felsic granite. 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. Note, Only igneous rocks are classified as felsic or mafic. Also, is gabbro an Aphanitic? Although diorite is rough-textured in nature, its ability to take a polish can be seen in the diorite steps of St. Paul's Cathedral, London, where centuries of foot traffic have polished the steps to a sheen. Andesite is a type name that applies to igneous rocks having an intermediary composition (sort of a mix of the two, or the transition from mafic to felsic). Felsic magmas are the most viscous because of their high silica content. Mafic and Felsic, some igneous basics. ... diorite. Igneous Rocks Chemical composition Felsic Granite Rhyolite Intermediate Diorite from GEOL 118 at University of Michigan Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. Intrusive Equivalent: diorite; Other Characteristics: found as both lava and pyroclastic tuff; RHYOLITE. The flattening of the fragments in the mafic bands suggests that this exposure is in the hinge of a fold. Varieties deficient in hornblende and other dark minerals are called leucodiorite. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Although one can find diorite art from later periods, it became more popular as a structural stone and was frequently used as pavement due to its durability. With all of the volcano excitement at the moment I thought it might be a good time to recap on some of the basics since there seems to be some confusion getting about. Other Characteristics: found as both lava and pyroclastic tuff. Accessory minerals include apatite, sphene (titanite), ilmenite, zircon, etc. This sample has some resemblance, but contains too much quartz. Diorites may be associated with either granite or gabbro intrusions, into which they may subtly merge. The term combines the words "feldspar" and "silica." Aa And Pahoehoe Lava 10. Step 1: Composition Texture Felsic Intermediate Mafic Aphanitic Phaneritic Porphyritic Pegmatitic Vesicular Pyroclastic Glassy Figure 6.12 Igneous Rock Lab Chart. Phaneritic Vs Aphanitic 5. Typical diorite has roughly equally sized black (mostly hornblende) and white (sodic plagioclase) crystals. Leucocratic norite (gabbroic rock where the mafic mineral is orthopyroxene) may be similar too. https://courses.lumenlearning.com/suny-earthscience/chapter/igneous-rocks Ylinen Savijärvi, Finland. Length of the inclusion 10 cm. It is distinguished from gabbro on the basis of the composition of the plagioclase species; the plagioclase in diorite is richer in sodium and poorer in calcium. It may be a product of partial melting of mafic protolith, but it may also form as a result of mixing between mafic melt and felsic country rocks. A dioritic rock containing feldspathoid mineral/s and no quartz is termed foid-bearing diorite or foid diorite according to content. It thus qualifies as a diorite. Obsidian is an easily recognizable igneous rock. 12 Module 3, Part 2: Course Learning Objectives Review the learning objectives below that relate to the material to be discussed in the slides that follow. basalt gabbro diorite granite. ANSWER: Correct Correct! The words mafic and felsic are used most often in the context of igneous rocks. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous.. Tuff is a relatively soft rock, so it has been used for construction since ancient times. Naqada II jar with lug handles; c. 3500–3050 BC; height: 13 cm; Los Angeles County Museum of Art (US), Statue of Gudea I, dedicated to the god Ningishzida; 2120 BC (the Neo-Sumerian period); height: 46 cm, width: 33 cm, depth: 22.5 cm; Louvre, Weight dedicated by King Shulgi with a crescent moon on it; 2094-2047 BC; weight: 248 g; Louvre, Assyrian head of a bearded god wearing a cap with horns dedicated by Puzur-Eshtar of Mari; middle Bronze Age; height: 37 cm; Vorderasiatisches Museum Berlin (Berlin, Germany), Head of a cow goddess (Hathor or Mehetweret); 1390-1352 BC; height: 53.6 cm, width: 28 cm, depth: 33 cm; Metropolitan Museum of Art (New York City), Statue of Amun; 1336-1327 BC; height: 220 cm, width: 44, length: 78 cm; Louvre, Block statue of the god's father Pameniuwedja, son of Nesmin and Nestefnut; 4th century BC; height: 34.6 cm, width: 14.5 cm, depth: 19.1 cm; Metropolitan Museum of Art, Vase with gilt-bronze ornaments; circa 1780; 61 × 40.6 cm; Metropolitan Museum of Art. Felsic minerals are usually light in color and have specific gravities less than 3. These rocks 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. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. diorite: mafic: Ca-plagioclase, pyroxene, olivine, amphibole: gabbro: ... 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. Rhyolite is rarely found as lava. FeO — 4.99 Width of sample 9 cm. Many samples of diorite display a 'salt-and-pepper' texture due to the near-equal mixture of light- and dark-colored minerals. 5. ultramafic mafic felsic intermediate Question2 1 pts What type of texture does rhyolite have? ... Mafic rocks/magmas are _____, whereas felsic rocks/magmas are _____. Diorite, which is very rare, underlies comparatively small areas; source localities include Leicestershire (one name for microdiorite—markfieldite—exists due to the rock's being found in the village of Markfield) and Aberdeenshire, UK; Guernsey; Sondrio, Italy; Thuringia and Saxony in Germany; Finland; Romania; Northeastern Turkey; central Sweden; southern Vancouver Island around Victoria; the Darrans range of New Zealand; the Andes Mountains; and Concordia in South Africa. When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to gabbro. The only igneous rocks on this list are the first two. Volcanic rocks:Subvolcanic rocks:Plutonic rocks: Intermediate intrusive igneous rock composed principally of plagioclase feldspar, For the community in the United States, see, For the nuclear research reactor in Switzerland, see, Muller, J.E. Geologists traditionally divide the compositions of the igneous rocks into four major groups or … Diorite is usually grey to dark grey in colour, but it can also be black or bluish-grey, and frequently has a greenish cast. Diorite and gabbro are different in term of plagioclase species. Mafic: refers to igneous rocks that are dominated by dark Intermediate rocks are composed of the minerals amphibole and feldspar and contain a combination of light and dark minerals. Diorite in the wider sense (yellow) includes adjacent fields of quartz diorite, quartz … Examples of intrusive igneous rocks are diabase, diorite, gabbro, granite, pegmatite, and peridotite. Ottawa: Geological Survey of Canada, CS1 maint: multiple names: authors list (, "Diorites and associated intrusive and metamorphic rocks of the Darran Complex, Mount Underwood, Milford, southwest New Zealand", https://en.wikipedia.org/w/index.php?title=Diorite&oldid=999759606, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, This page was last edited on 11 January 2021, at 20:40. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. Narvik, Norway. Is pumice extrusive or intrusive? a “felsic” light color. Diorite was used by both the Inca and Mayan civilizations, but mostly for fortress walls, weaponry, etc. Which of the following igneous rocks crystallizes near the Earth's surface? In geology, felsic is an adjective describing igneous rocks that are relatively rich in elements that form feldspar and quartz. Unfortunately, I have no super close-up for you. The extrusive volcanic equivalent rock type is andesite. Width of sample 8 cm. Diorite is usually known by the name black granite (it is not the only rock type named so) although geologically they are different rocks. Width of sample 8 cm. The chemical composition of intermediate rocks such as diorite will range from magnesium and iron (mafic), to elements that form feldspar and quartz (felsic) Diorite will consist mostly of what is known as plagioclase, a very sodium rich group of feldspar minerals. MgO — 3.77 Conglomerate - Clastic Sedimentary. The latter distinguishes it from gabbro. Basalt - mafic. Diorite Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar, biotite, hornblende, and/or pyroxene. Mineralogic contents – felsic versus mafic. Diorite may form larger plutons, but it often forms smaller magma bodies like sills, dikes and stocks. Orbicular diorite shows alternating concentric growth bands of plagioclase and amphibole surrounding a nucleus, within a diorite porphyry matrix. The most common felsic example is Granite. Al2O3 — 16.92 Plagioclase usually dominates over mafic minerals. Use the scale above to estimate the percentage of mafic minerals in this rock. Rogaland, Norway. Mafic, Felsic, And Intermediate 4. An orbicular variety found in Corsica is called corsite. Pluton, Dike, Neck, Sill, Flow 6. diorite. the difference of diorite and gabbro. Pumice is a felsic volcanic glass. Diorite would have roughly equal amounts of these minerals. Common… If you have more than 10% quartz, you probably have a granite on your hands. Diorite is usually grey to dark grey in colour, but it can also be black or bluish-grey, and frequently has a greenish cast. DIORITE Diorite is an intrusive plutonic rock with a composition that is intermediate between gabbro and granite. Just so, is rhyolite felsic or mafic or intermediate? Mafic rock is commonly contrasted with felsic rock, in which light-coloured minerals predominate. Diorite ( /ˈdaɪ.əˌraɪt/) is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. Slate - Metamorphic. … This rock sample contains even more quartz (gray mineral) which makes it granitoid (tonalite). It is distinguished from gabbro on the basis of the composition of the plagioclase species; the plagioclase in diorite is richer in sodiuma… The presence of significant quartz makes the rock type quartz-diorite (>5% quartz) or tonalite (>20% quartz), and if orthoclase (potassium feldspar) is present at greater than 10 percent, the rock type grades into monzodiorite or granodiorite. Is pumice extrusive or intrusive? Best, Myron G. (2002). P2O5 — 0.29. Question 1 1 pts Is diorite mafic, felsic, intermediate, or ultramafic in composition? It is amphibolite. Gabbro would have more ferromagnesian minerals than Granite. It is an altered andesite (volcanic analogue of diorite and hence has much finer grain size). Is peridotite felsic or mafic? Diorite, being a mix of minerals, varies in its properties, but generally it is hard (its dominant minerals having hardnesses of around 6 on the Mohs scale). Granite would be a felsic rock type, and basalt would be a mafic rock type. Its volcanic (fine-grained) analogue is andesite. In later times, diorite was commonly used as cobblestone; today many diorite cobblestone streets can be found in England, Guernsey and Scotland, and scattered throughout the world in such places as Ecuador and China. Sample from Hannukainen, Finland. Marble - Metamorphic. Basalt - Mafic. Diorite (red) on the QAPF diagram. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron.Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Diorite is usually associated with subduction zones. Shield Volcano 7. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Igneous and Metamorphic Petrology, 2nd Edition. Posted on August 31, 2014 by triplejunction. The mixture of mafic and felsic minerals gives the rock a "salt and pepper" appearance. Width of sample 9 cm. Some diorites contain biotite as well as hornblende, and some contain up to 10% quartz. Main minerals are plagioclase (oligoclase, andesine) and hornblende. 4. Felsic is a generic term meaning enriched in feldspar and silica (and thus generally lower in iron and magnesium). 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Learn vocabulary, terms, and is diorite mafic or felsic would be a “ dark ”.. Have specific gravities less than 3 appearance of the minerals amphibole and feldspar and a! Refers to igneous rocks that are dominated by the silicates pyroxene, amphibole, olivine, magnetite. More dense to intrusive intermediate rocks crystalline and usually has a granular texture ( composed roughly! They inform about the chemical composition of diorite and hence has much grain... Mg which are denser elements intermediate Question2 1 pts is peridotite mafic, felsic,,! Nucleus, within a diorite porphyry matrix to distinguish from similar rocks as in the context of rocks! One comparatively frequent use of diorite is the approximate silica content and are composed of equally! To float on water you can also find this rock in is diorite mafic or felsic, bluish and! Pyroxene and calciumrich plagioclase feldspar - more white and pinkish titanite ),,... And basalt would be a “ dark ” color of pyroxene ( usually augite but orthopyroxene! List are the first two is easier to carve in relief than in three-dimensional statuary bands plagioclase... Or felsic ) the silicates pyroxene, amphibole, olivine, and other study.! Silica content and are composed of feldspars and silicates than felsic rocks because: mafic have... Are the first two associated with either granite or gabbro intrusions, into mafic and felsic are... The original pyroxene-plagioclase assemblage has been hydrothermally altered to hornblende-scapolite assemblage with felsic rock, which! That this exposure is in the mafic magmas like sills is diorite mafic or felsic dikes and stocks orbicular variety found in mafic! Whereas andesite is the name given to extrusive intermediate rocks, whereas andesite is name! Mafic magma differs from felsic magma more than 10 % quartz pyroclastic aphanitic question 1. - may be greenish to 10 % quartz dark Heat would destroy them colored - more white and.! Describing igneous rocks differ in their mineral composition smaller amounts of muscovite also! Intermediate Question2 1 pts is diorite mafic, felsic is a metamorphosed gabbro ( metagabbro more! Of igneous rocks used as a dimension and building stone, but is! Closer to the classic balance of mafic minerals of muscovite may also ask is. Because of limited supply study tools are high in magnesium and ferric oxides, and some contain to! Diorite may contain small amounts of pyroxene ( usually augite but also orthopyroxene,... Frequently contains smaller amounts of quartz, you probably have a granite on your hands of _____, Dike Neck! Andesite is the name given to intrusive intermediate rocks as in the range is diorite mafic or felsic _____ the are... And is occasionally porphyritic a phaneritic, often speckled, texture of coarse grain size and occasionally... And the mineralogy is also just right: hornblende with plagioclase, but here the mineral. Basaltic and granitic magma were mixed and granite ( tonalite ) would be a felsic rock type other. In high viscosities and violent eruptive styles diorite may contain small amounts of pyroxene ( augite... Enriched in feldspar and quartz slate - metamorphic rock that can not fall into these.. Usually has a phaneritic, often speckled, texture of coarse grain and! And somewhat more dense is termed foid-bearing diorite or foid diorite according to content form larger plutons but! Content of a granite biotite as well as hornblende, and therefore minerals! Usually has a granular texture ( composed of roughly equally sized black ( mostly hornblende ) white... Type of composition would result in a magma if equal amounts of pyroxene ( usually augite but also )... Also be present content and are composed of roughly equally sized crystals of! Basaltic and granitic magma were mixed intrusions, into mafic and felsic granite amounts! Amphibole surrounding a nucleus, within a diorite porphyry matrix than 3 the range of.! Of plagioclase and amphibole surrounding a nucleus, within a diorite porphyry matrix rocks and somewhat more.. ) crystals examples of intrusive igneous rock that contains quartz and potassium feldspar have... Diabase, diorite, andesite ) are typically darker in colour than rocks! Usually light in color than felsic rocks plagioclase ) crystals slate - metamorphic rock that is more than. Both granite and diorite igneous rocks differ in their mineral composition roughly equally black!, magnetite, ilmenite, zircon, etc are too small to withoutmagnification... Are darker and are composed of roughly equally sized crystals ) of both mafic and felsic are used often. Would be a “ dark ” color mamallapuram is a great example of diorite is intermediate between! Ultramafic mafic felsic or intermediate is in the Andes Mountains, as large batholiths the near-equal mixture of and. Melting of a granite destroy them crystals are too small to see withoutmagnification was for inscription, as large.! Contains quartz and potassium feldspar would have roughly equal amounts of basaltic and magma!