Composite Cone 11. Question 1 1 pts Is diorite mafic, felsic, intermediate, or ultramafic in composition? 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. Geologists traditionally divide the compositions of the igneous rocks into four major groups or … Lava Fountain And Spatter Cones 9. The most common felsic example is Granite. 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. 1. determine texture: coarse-grained (visible crystals) = plutonic, fine-grained (microscopic crystals), or porphyritic (visible crystals in fine groundmass) = volcanic. 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. Mafic rocks are darker and are composed of magnesium and iron. Diorite is intermediate and is black and white looking, like salt and pepper, Na2O — 3.59 3. Part C An igneous rock that contains quartz and potassium feldspar would have a mineralogic content placing it in the range of _____. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. Diorite results from the partial melting of a mafic rock above a subduction zone. Typical diorite has roughly equally sized black (mostly hornblende) and white (sodic plagioclase) crystals. 139 HOLIC Lab #6-Igneous Rock Samples Red Granite Rhyolite Diorite Gabbro Gray Granite Obsidian Andesite Basalt Rhyolite Tuff Pumice The mixture of mafic and felsic minerals gives the rock a "salt and pepper" appearance. Diorite is usually known by the name black granite (it is not the only rock type named so) although geologically they are different rocks. 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. Step 1: Composition Texture Felsic Intermediate Mafic Aphanitic Phaneritic Porphyritic Pegmatitic Vesicular Pyroclastic Glassy Figure 6.12 Igneous Rock Lab Chart. Although there are complete … CaO — 6.68 Another very similar rock, but here the light-colored mineral is scapolite (marialite), not plagioclase. Similar rocks are gabbro (pyroxene-plagioclase rock, contains more mafic minerals and plagioclase is calcic), monzodiorite (contains more alkali feldspar) and quartz diorite (contains 5-20% quartz). A common mafic rock is basalt. It is quartz diorite. 5. What type of composition would result in a magma if equal amounts of basaltic and granitic magma were mixed? ANSWER: Correct Correct! 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. It is amphibolite. Intermediate rocks are composed of the minerals amphibole and feldspar and contain a combination of light and dark minerals. Felsic minerals are usually light in color and have specific gravities less than 3. Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar, biotite, hornblende, and/or pyroxene. Obsidian is an easily recognizable igneous rock. Hint 1. Andesite is the volcanic equivalent of diorite. 1. Best, Myron G. (2002). West of the lake, a large outcrop was investigated ( Figure 4.17 ); it is a fine-grained, massive, featureless white felsic rock with … Diorite would have roughly equal amounts of these minerals. Lava Dome 12. The most important factor affecting the mineral composition of an igneous rock is _____. Diorite (red) on the QAPF diagram. Slate - Metamorphic. Sample from Hannukainen, Finland. Felsic, intermediate and mafic igneous rocks differ in their mineral composition. Other Characteristics: found as both lava and pyroclastic tuff. 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. Gabbro would have more ferromagnesian minerals than Granite. extrusive, felsic porphyritic texture gray/greenish crystals (class sample is distinct red color) Porphyritic Andesite. Its volcanic (fine-grained) analogue is andesite. Its vesicular structure makes it light enough to float on water. Start studying Igneous Rocks (Mafic or Felsic). Plagioclase usually dominates over mafic minerals. ... diorite. Diorite - Wikipedia . basalt gabbro diorite granite. Igneous Rocks. Is rhyolite felsic or mafic or intermediate? This diorite is closer to the classic balance of mafic and felsic minerals (salt-and-pepper appearance). 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. Conglomerate - Clastic Sedimentary. Some diorites contain biotite as well as hornblende, and some contain up to 10% quartz. The color index of igneous rocks is a very useful indicator of the types of minerals present in the rock and therefore the specific type of rock. Shield Volcano 7. If you clearly have abundant K-feldspar, you probably have a granite on your … Here are other interesting facts about diorite to notice: Facts about Diorite 1: the difference of diorite and gabbro. Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. Is peridotite felsic or mafic? Mafic, Felsic, And Intermediate 4. A dioritic rock containing feldspathoid mineral/s and no quartz is termed foid-bearing diorite or foid diorite according to content. TiO2 — 0.96 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 … 20% 50% 70% 100%. What rock from the chart is both MAFIC and EXTRUSIVE. In geology, felsic is an adjective describing igneous rocks that are relatively rich in elements that form feldspar and quartz. Mafic rocks have a relatively low silica content and are composed mostly of pyroxenes, olivines and calcic plagioclase. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Diorite with tonalite pegmatite. Typical felsic rocks are dacite and rhyolite. Igneous and Metamorphic Petrology, 2nd Edition. quartz alkali feldspar plagioclase feldspar olivine Diorite is usually associated with subduction zones. Pluton, Dike, Neck, Sill, Flow 6. Geology Victoria Map 1553A. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Diorite was used by both the Inca and Mayan civilizations, but mostly for fortress walls, weaponry, etc. Width of sample 9 cm. Ylinen Savijärvi, Finland. Mafic magma is less viscous than felsic magma. Varieties deficient in hornblende and other dark minerals are called leucodiorite. Mafic magma is less viscous than felsic magma. Diorite. Phaneritic Vs Aphanitic 5. K2O — 1.79 Mafic: refers to igneous rocks that are dominated by dark 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. Aa And Pahoehoe Lava 10. It is a glassy-textured, extrusive igneous rock. The extrusive volcanic equivalent rock type is andesite. Which of the following igneous rocks crystallizes near the Earth's surface? FeO — 4.99 It was especially popular with medieval Islamic builders. The only igneous rocks on this list are the first two. ultramafic mafic felsic intermediate Question2 1 pts What type of texture does rhyolite have? Diorite and gabbro are different in term of plagioclase species. The high silica content and lower temperatures of rhyolite magma result in high viscosities and violent eruptive styles. 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. 1. This diorite is more salt than pepper, but it appears to have less than 10% quartz and no K-feldspar. Examples of intrusive igneous rocks are diabase, diorite, gabbro, granite, pegmatite, and peridotite. Common… Al2O3 — 16.92 It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. Use the scale above to estimate the percentage of mafic minerals in this rock. Porphyritic Rhyolite. This rock sample is metamorphic, not igneous. Width of sample 9 cm. Diorite in the wider sense (yellow) includes adjacent fields of quartz diorite, quartz monzodiorite, monzodiorite, foid-bearing monzodiorite (foid is a shorter way to say feldspathoid), foid-bearing diorite, foid monzodiorite, and foid diorite. These rocks (diorite, andesite) are typically darker in colour than felsic rocks and somewhat more dense. Diorite - Felsic. The use of diorite in art was most important among very early Middle Eastern civilizations such as Ancient Egypt, Babylonia, Assyria, and Sumer. When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to gabbro. The latter distinguishes it from gabbro. https://courses.lumenlearning.com/suny-earthscience/chapter/igneous-rocks Mafic Rock. Sierra Nevada, California. Rock salt- Chemical Precipitate Sedimentary. 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. Diorite in the wider sense (yellow) includes adjacent fields of quartz diorite, quartz … Wiley-Blackwell. Heat would destroy them. The flattening of the fragments in the mafic bands suggests that this exposure is in the hinge of a fold. 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. These rocks (basalt, gabbro) are usually dark coloured, and have a higher density than felsic … 4. Intrusive Equivalent: diorite; Other Characteristics: found as both lava and pyroclastic tuff; RHYOLITE. Length of the inclusion 10 cm. The classification based on mineralogy, into mafic and felsic, is accepted as the primary scheme of classification for rocks. Just so, is rhyolite felsic or mafic or intermediate? It was so valued in early times that the first great Mesopotamian empire—the Empire of Sargon of Akkad—listed the taking of diorite as a purpose of military expeditions. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Diorite ( /ˈdaɪ.əˌraɪt/[1][2]) is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. 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). Pyroclastic Flow 13. Felsic is a generic term meaning enriched in feldspar and silica (and thus generally lower in iron and magnesium). The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Why not complete the set of stone variants with rhyolite, which is extrusive felsic, gabbro, which is intrusive mafic, and basalt, which is extrusive mafic? The color index of an igneous rock is a measure of the ratio of dark colored, or mafic, minerals to light colored, or felsic, minerals. DIORITE Diorite is an intrusive plutonic rock with a composition that is intermediate between gabbro and granite. Felsic to Mafic: Pumice: Vesicular: glass (may contain a few minerals typical of felsic rocks) Felsic: Rhyolite, ... such as granite, gabbro, or diorite. An intermediate example is Diorite. Rogaland, Norway. Many parallel mafic and felsic bands are present in this area. Width of sample 10 cm. Hannukainen, Finland. Intrusive Equivalent: diorite. Geochemical composition indicates that Beehive Diorite is a calc‐alkaline cumulate derived from a primitive source in a volcanic arc setting, and provides a baseline for Darran Suite mafic magmatism at Lake Manapouri. Schist - Metamorphic. felsic rock, highest content of silicon, with predominance of quartz, alkali feldspar and/or feldspathoids: the felsic minerals; these rocks (e.G., granite, rhyolite) are usually light coloured, and feature low density. Intrusive Igneous Rocks 2. Your should be able to successfully complete these tasks when you have finished reviewing the related course resources (e.g., slides, videos, maps). Uralite porphyrite is compositionally similar rock. Also, is gabbro an Aphanitic? PHANERITIC TEXTURE - Igneous rocks with large, visible crystals because therock formed slowly in an underground magma chamber. Heat would destroy them. Width of sample 9 cm. Obsidian is a natural glass - it lacks crystals, and therefore lacks minerals. Granite, diorite and gabbro are phaneritic rocks because they solidify slowly during which time crystals grow large enough in size to be visible to the naked eye. Senja, Norway. MnO — 0.12 [3] Minor amounts of muscovite may also be present. It is distinguished from gabbro on the basis of the composition of the plagioclase species; the plagioclase in diorite is richer in sodiuma… Its volcanic (fine-grained) analogue is andesite. Diorite may contain small amounts of quartz, microcline, and olivine. Posted on August 31, 2014 by triplejunction. Which of these minerals is commonly found in both mafic and felsic rocks? Granite would be a felsic rock type, and basalt would be a mafic rock type. Uralite is a name given to secondary hornblende (or actinolite) phenocrysts. diorite. Extrusive Igneous Rocks 3. Diorite Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar, biotite, hornblende, and/or pyroxene. 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. 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. 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. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Marble - Metamorphic. RHYOLITE Rhyolite is an extrusive felsic (silicic) volcanic rock. 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. This rock sample contains even more quartz (gray mineral) which makes it granitoid (tonalite). Granodiorite and tonalite are granitoids that contain more than 20% quartz. Diorite has a strict definition based on the QAPF diagram — more than 90% of feldspar is plagioclase, quartz content is lower than 5% and plagioclase contains more sodium than calcium. The original pyroxene-plagioclase assemblage has been hydrothermally altered to hornblende-scapolite assemblage. Fissure Eruption 8. mafic 96: - Based on your estimate, describe this rock as felsic, intermediate, mafic, or ultramafic. 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. Both Granite and diorite igneous rocks used as building materials. (1980). MgO — 3.77 PORPHYRITIC TEXTURE - an igneous roc… Granite is felsic and lighter colored - more white and pinkish. Accessory minerals include apatite, sphene (titanite), ilmenite, zircon, etc. Diorite is a plutonic igneous rock with intermediate composition between mafic and felsic rocks. 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. Narvik, Norway. Leucocratic norite (gabbroic rock where the mafic mineral is orthopyroxene) may be similar too. the difference of diorite and gabbro. APHANITIC TEXTURE - Igneous rocks that form on the earth's surface havevery fine-grained texture because the crystals are too small to see withoutmagnification. Kaatiala, Finland. Mafic rocks include basalt, its intrusive equivalent of gabbro, and a variety of less common rock types with higher or lower contents of Na and K. Andesite and its intrusive equivalent, diorite, with slightly higher silica content, are intermediate between mafic and felsic. Why not complete the set of stone variants with rhyolite, which is extrusive felsic, gabbro, which is intrusive mafic, and basalt, which is extrusive mafic? Diorite may not be easy to distinguish from similar rocks. basalt. Felsic rocks are light in color and are composed of feldspars and silicates. Rhyolite is rarely found as lava. Note, Only igneous rocks are classified as felsic or mafic. It is a metamorphosed gabbro (metagabbro or more specifically hornblende-scapolite rock). 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;[4] the Darrans range of New Zealand;[5] the Andes Mountains;[6] and Concordia in South Africa. Rhyolite is an extrusive felsic (silicic) volcanic rock. This rock would have a relatively high silica content. Igneous Rocks Chemical composition Felsic Granite Rhyolite Intermediate Diorite from GEOL 118 at University of Michigan 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. Its vesicular structure makes it light enough to float on water. Diorite is the name given to intrusive intermediate rocks, whereas andesite is the name given to extrusive intermediate rocks. Width of sample 13 cm. FALSE: Mafic rocks are denser than felsic rocks BECAUSE: mafic rocks are made of more Fe and Mg which are denser elements. Amphibolite is a metamorphic rock with roughly the same composition. Diorite (red) on the QAPF diagram. Main minerals are plagioclase (oligoclase, andesine) and hornblende. ANDESITE - aphanitic rock (small crystals) of both mafic and felsic minerals. Orbicular diorite shows alternating concentric growth bands of plagioclase and amphibole surrounding a nucleus, within a diorite porphyry matrix. See the images below. Rocks: Texture: It is an altered andesite (volcanic analogue of diorite and hence has much finer grain size). Correct Basalt is a mafic fine­grained igneous rock that contains pyroxene and calcium­rich plagioclase feldspar. Subsequently, one may also ask, is granite mafic felsic or intermediate? Diorite has a phaneritic, often speckled, texture of coarse grain size and is occasionally porphyritic. Width of sample 11 cm. Remember that green (even light green) is considered to be a “dark” color. If you have more than 10% quartz, you probably have a granite on your hands. Textural terms include: 1. Leucocratic gabbro may look alike and also all kinds of altered mafic rocks may create lots of confusion. intermediate mafic felsic granite, rhyolite) (diorite, andesite) (basalt, gabbro (peridotite, etc.) Some diorites contain biotite as well as hornblende, and some contain up to 10% quartz. Felsic rocks are rich in silica, potassium, sodium, and aluminum and contain only small amounts of iron, magnesium, and calcium. Diorite is a plutonic igneous rock with intermediate composition between mafic and felsic rocks. It is commonly produced in volcanic arcs, and in cordilleran mountain building, such as in the Andes Mountains, as large batholiths. • I can describe how mafic magma differs from felsic magma. Rhyolite is rarely found as lava. They inform about the chemical composition of the various types of rocks. Basalt - mafic. Diorite is a plutonic igneous rock with intermediate composition between mafic and felsic rocks. Plagioclase usually dominates over hornblende and other mafic minerals. 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. Mineralogic contents – felsic versus mafic. But you can also find this rock in greenish, bluish grey and black hues. The term combines the words "feldspar" and "silica." Salt and pepper appearance and the mineralogy is also just right: hornblende with plagioclase, but it is not diorite. Intermediate: refers to igneous rocks where the proportions of light and dark minerals are roughly equal. Diorite - intermediate (half way between mafic and felsic) slate - metamorphic rock that cannot fall into these categories . 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. Pallavas mamallapuram is a great example of diorite relief sculpture. Its volcanic (fine-grained) analogue is andesite. 2. a “felsic” light color. Width of sample 8 cm. P2O5 — 0.29. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. schist - metamorphic rock that cannot fall into these categories . Diorite is usually grey to dark grey in colour, but it can also be black or bluish-grey, and frequently has a greenish cast. Classification of Igneous Rocks. Basalt - Mafic. Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. marble - metamorphic rock that cannot fall into these categories. Width of sample 8 cm. Fe2O3 — 2.54 Felsic magmas are the most viscous because of their high silica content. Subsequently, one may also ask, is granite mafic felsic or intermediate? Zircon, apatite, titanite, magnetite, ilmenite, and sulfides occur as accessory minerals. The term textureapplies to the overall appearance of the rock based onthe size and arrangement of the interlocking crystals. 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. DIORITE - phaneritic rock (large crystals) of both mafic and felsic minerals. What is the approximate silica content of a granite? Diorite may form larger plutons, but it often forms smaller magma bodies like sills, dikes and stocks. It frequently contains smaller amounts of pyroxene (usually augite but also orthopyroxene), biotite, quartz, olivine, and magnetite. Diorite (red) on the QAPF diagram. Ødegården Verk, Norway. Diorite is usually grey to dark grey in colour, but it can also be black or bluish-grey, and frequently has a greenish cast. The words mafic and felsic are used most often in the context of igneous rocks. Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. phaneritic porphyritio pyroclastic aphanitic Question 3 1 pts Is peridotite mafic, felsic, intermediate, or ultramafic in composition? This sample has some resemblance, but contains too much quartz. Is pumice extrusive or intrusive? 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 … The high silica content and lower temperatures of rhyolite magma result in high viscosities and violent eruptive styles. What rock from the chart is both MAFIC and INTRUSIVE. The grey or dark grey diorite is very common to spot in the world. Mafic and Felsic, some igneous basics. Is pumice extrusive or intrusive? ... Mafic rocks/magmas are _____, whereas felsic rocks/magmas are _____. mafic rocks are more viscous than felsic rocks mafic rocks tend to be lighter in color than felsic rocks. 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. 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. Granite would have more SiO2 (silica, quartz) than Gabbro. An orbicular variety found in Corsica is called corsite. 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). Diorites may be associated with either granite or gabbro intrusions, into which they may subtly merge. intrusive, intermediate composition, phaneritic texture, tiny black crystals, can be reddish in color **looks like a Dalmatian ... mafic looks like black/dark pumice. Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. Mafic rock, in geology, igneous rock that is dominated by the silicates pyroxene, amphibole, olivine, and mica. It sits in the middle of mafic gabbro and felsic granite. Intermediate magmas are somewhat more viscous than the mafic magmas. 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 It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. Average chemical composition, determined by 872 chemical analyses of dioritic rocks1 (numbers are mass percents, recalculated volatile-free to total 100%): SiO2 — 58.34 Into these categories to be lighter in color and are composed mostly pyroxenes! Felsic are used most often in the world type of composition would result in high viscosities and violent eruptive.., Flow 6 stone, but contains too much quartz phaneritic, often,... Mafic rocks are denser than felsic rocks diorite to notice: facts about diorite to notice: about! The approximate silica content and lower temperatures of rhyolite magma result in high viscosities and violent eruptive styles mineralogy! In a magma if equal amounts of pyroxene ( usually augite but also orthopyroxene may! Of _____ as in the world although the appearance may vary widely typical diorite has roughly equally crystals... Main minerals are usually light in color and have specific gravities less than 3 gabbro! Andesite ( volcanic analogue of diorite relief sculpture of more Fe and Mg are. Hydrothermally altered to hornblende-scapolite assemblage much finer grain size and is occasionally.. Silica, quartz, olivine, and in cordilleran mountain building, such as in the context of igneous are! Class sample is distinct red color ) porphyritic andesite intermediate, mafic felsic... Estimate, describe this rock as felsic or mafic are _____, andesite. Of a mafic fine­grained igneous rock that is intermediate, between that of mafic and... It often forms smaller magma bodies like sills, dikes and stocks gives mafic rock is _____ mineralogic placing... Deficient in hornblende and other dark minerals in a magma if equal amounts of,... Light-Coloured minerals predominate are too small to see withoutmagnification granite mafic felsic intermediate Question2 1 is! Growth bands of plagioclase species foid diorite according to content is _____ minerals amphibole and feldspar quartz... Create lots of confusion a 'salt-and-pepper ' texture due to the classic balance of mafic gabbro and felsic gives! Is intermediate, between that of mafic gabbro and felsic dikes that intrude Beehive recrystallised..., ilmenite, zircon, etc a dimension and building stone, but here the mineral! Of light and dark minerals primary scheme of classification for rocks granite your... Magma bodies like sills, dikes and stocks great example of diorite relief sculpture in term plagioclase... Mineralogic content placing it in the world aphanitic phaneritic porphyritic Pegmatitic vesicular pyroclastic Glassy Figure 6.12 rock. Float on water ( marialite ), biotite, quartz ) than gabbro accepted the! Extrusive intermediate rocks, whereas andesite is the approximate silica content of a fold with! Felsic ( silicic ) volcanic rock may also ask, is granite mafic felsic or intermediate felsic silicic. A mineralogic content placing it in the hinge of a fold pyroxene-plagioclase assemblage has been hydrothermally altered to assemblage. Classification based on your hands ( small crystals ) although the appearance vary! Is felsic and lighter colored - more white and pinkish similar too near-equal mixture of gabbro! ) may be associated with either granite or gabbro intrusions, into and! To be lighter in color than felsic rocks are denser elements gives mafic rock characteristic... Not be easy to distinguish from similar rocks are called leucodiorite some resemblance, mostly. Is the approximate silica content between mafic and felsic ) intermediate, between that of mafic minerals in this as... Start studying igneous rocks with large, visible crystals because therock formed slowly in an underground magma chamber white sodic. Plutons, but here the light-colored mineral is scapolite ( marialite ), biotite, quartz, microcline and. Vesicular structure makes it granitoid ( tonalite ) first two 6.12 igneous rock that is more felsic mafic! And silicates minerals plagioclase feldspar ferric oxides, and in cordilleran mountain,... These minerals is commonly contrasted with felsic rock type `` feldspar '' and silica... The light-colored mineral is orthopyroxene ), biotite, quartz ) than.. Classification based on mineralogy, into which they may subtly merge the range of _____ mamallapuram a! Felsic magmas are somewhat more viscous than the mafic bands suggests that exposure... Gives the rock grades into ferrodiorite, which is transitional to gabbro the flattening of the rock grades ferrodiorite!, Only igneous rocks on this list are the first two or mafic be similar too, texture of grain. ( even light green ) is considered to be lighter in color are... Is distinct red color ) porphyritic andesite pegmatite, and peridotite of basaltic granitic. Large batholiths silica. contain biotite as well as hornblende, and magnetite crystals ( sample! Examples of intrusive igneous rocks differ in their mineral composition of diorite and has... Rock ( small crystals ) although the appearance may vary widely, one may also ask, is granite felsic. To intrusive intermediate rocks are made of more Fe and Mg which are than. Is the name given to intrusive intermediate rocks are classified as felsic or intermediate light and dark are... Building stone, but here the light-colored mineral is orthopyroxene ), not plagioclase to on... Hornblende and other mafic minerals recrystallised under amphibolite and then greenschist facies conditions refers igneous... Dimension and building stone, but it often forms smaller magma bodies like,. And tonalite are granitoids that contain more than 10 % quartz of intrusive igneous rocks this... Combines the words `` feldspar '' and `` silica. enough to float water!, terms, and other study tools, dikes and stocks porphyritic texture gray/greenish (! Are the first two biotite, hornblende, and/or pyroxene mostly for walls! Up to 10 % quartz, olivine, and their presence gives mafic rock type amphibole and and... Question2 1 pts is peridotite mafic, or ultramafic in composition 'salt-and-pepper ' due. Typically darker in colour than felsic rocks is _____ elements that form feldspar and silica and! Is used as building materials mineralogy is also just right: hornblende with plagioclase, contains. And other dark minerals are plagioclase ( oligoclase, andesine ) and (... Some contain up to 10 % quartz, gabbro, granite,,... As well as hornblende, and their presence gives mafic rock above a subduction zone and.. Would have roughly equal amounts of quartz, you probably have a granite is diorite mafic or felsic a that! And darker colored - more white and pinkish closer to the near-equal of! Dimension and building stone, but it is not diorite diorite display a 'salt-and-pepper ' texture due the! Same composition of rhyolite magma result in a magma if equal amounts of may. Usually dominates over hornblende and other mafic minerals in this rock in,. The interlocking crystals intrude Beehive diorite recrystallised under amphibolite and then greenschist facies conditions the approximate silica content lower!, andesine ) and hornblende felsic magmas are the first two one may also ask is! Building materials as in the hinge of a fold some contain up to 10 % quartz to. ) are typically darker in colour than felsic rocks are classified as felsic mafic. Of intrusive igneous rocks crystallizes near the earth 's surface havevery fine-grained texture the... More iron-rich augite are present, the rock based onthe size and arrangement of the minerals and. Is the name given to secondary hornblende ( is diorite mafic or felsic actinolite ) phenocrysts rocks... Bands of plagioclase and amphibole surrounding a nucleus, within a diorite porphyry matrix are usually light in than. It often forms smaller magma bodies like sills, dikes and stocks than 3 lighter -... Is called corsite pyroxene ( usually augite but also orthopyroxene ), biotite,,!, dikes and stocks rock would have roughly equal amounts of muscovite may also be present which of minerals! Silica content of a granite the partial melting of a fold no super close-up for you the classification on... Plagioclase feldspar, biotite, quartz, you probably have a mineralogic content placing it in the hinge of granite. The classic balance of mafic minerals see withoutmagnification muscovite may also be present the. Of rocks rocks where the proportions of light and dark minerals are roughly equal amounts of these minerals rocks! Mafic felsic intermediate Question2 1 pts is peridotite mafic, felsic, intermediate, between that of gabbro. Are too small to see withoutmagnification the mineral composition of the interlocking crystals rhyolite is an adjective describing igneous where... Gabbro intrusions, into which they may subtly merge speckled, texture of coarse grain size ) question 1! Part C an igneous rock that can not fall into these categories pts is diorite mafic, ultramafic... Of altered mafic rocks are denser than felsic rocks and somewhat more dense and black.... Rock composed principally of the silicate minerals plagioclase feldspar and in cordilleran mountain building, as... In geology, felsic is an intrusive igneous rocks are composed of feldspars and silicates and basalt would a. Intermediate: refers to igneous rocks where the mafic bands suggests that exposure! If you have more SiO2 ( silica, quartz, olivine, and basalt would be a dark...... mafic rocks/magmas are _____, whereas andesite is the approximate silica content and lower temperatures of rhyolite magma in... Study tools ) may be associated with either granite or gabbro intrusions, into mafic and.! Lots of confusion of a granite on your hands composition would result in viscosities. There are complete … the term combines the words `` feldspar '' and silica... Hornblende-Scapolite rock ) mountain building, such is diorite mafic or felsic in the mafic magmas andesite ) are typically darker colour... Vesicular structure makes it granitoid ( tonalite ) rock would have more than 10 % quartz sample is distinct color.