Diorite: intermediate with a phaneritic texture (crystals are so coarse that individual minerals can be distinguished with the naked eye) Rhyolite: felsic with an aphanitic texture (so fine-grained that their component mineral crystals are not detectable by the unaided eye) This sample has some resemblance, but contains too much quartz. 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 Mafic magma is less viscous than felsic magma. Pumice is a felsic volcanic glass. Mafic rocks are darker and are composed of magnesium and iron. The most important factor affecting the mineral composition of an igneous rock is _____. CaO — 6.68 Learn vocabulary, terms, and more with flashcards, games, and other study tools. Diorite is intermediate and is black and white looking, like salt and pepper, Textural terms include: 1. Felsic is a generic term meaning enriched in feldspar and silica (and thus generally lower in iron and magnesium). Width of sample 11 cm. It is a glassy-textured, extrusive igneous rock. 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. Remember that green (even light green) is considered to be a “dark” color. Another very similar rock, but here the light-colored mineral is scapolite (marialite), not plagioclase. 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. Diorite has a phaneritic, often speckled, texture of coarse grain size and is occasionally porphyritic. Igneous Rocks Chemical composition Felsic Granite Rhyolite Intermediate Diorite from GEOL 118 at University of Michigan This rock sample contains even more quartz (gray mineral) which makes it granitoid (tonalite). 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 chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Part C An igneous rock that contains quartz and potassium feldspar would have a mineralogic content placing it in the range of _____. Felsic to Mafic: Pumice: Vesicular: glass (may contain a few minerals typical of felsic rocks) Felsic: Rhyolite, ... such as granite, gabbro, or diorite. It is amphibolite. RHYOLITE Rhyolite is an extrusive felsic (silicic) volcanic rock. K2O — 1.79 Intrusive Equivalent: diorite. Its vesicular structure makes it light enough to float on water. The term textureapplies to the overall appearance of the rock based onthe size and arrangement of the interlocking crystals. • I can describe how mafic magma differs from felsic magma. This rock sample is metamorphic, not igneous. 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 Wiley-Blackwell. This diorite is more salt than pepper, but it appears to have less than 10% quartz and no K-feldspar. One comparatively frequent use of diorite was for inscription, as it is easier to carve in relief than in three-dimensional statuary. It is distinguished from gabbro on the basis of the composition of the plagioclase species; the plagioclase in diorite is richer in sodiuma… If you have more than 10% quartz, you probably have a granite on your hands. Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. Length of the inclusion 10 cm. Leucocratic norite (gabbroic rock where the mafic mineral is orthopyroxene) may be similar too. Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. Diorite is the name given to intrusive intermediate rocks, whereas andesite is the name given to extrusive intermediate rocks. Hannukainen, Finland. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. It is quartz diorite. What is the approximate silica content of a granite? 1. 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). Also, is gabbro an Aphanitic? Just so, is rhyolite felsic or mafic or intermediate? Step 1: Composition Texture Felsic Intermediate Mafic Aphanitic Phaneritic Porphyritic Pegmatitic Vesicular Pyroclastic Glassy Figure 6.12 Igneous Rock Lab Chart. Posted on August 31, 2014 by triplejunction. Although there are complete … It is a metamorphosed gabbro (metagabbro or more specifically hornblende-scapolite rock). Marble - Metamorphic. Diorite may form larger plutons, but it often forms smaller magma bodies like sills, dikes and stocks. 20% 50% 70% 100%. Mafic magma is less viscous than felsic magma. Na2O — 3.59 Is pumice extrusive or intrusive? Felsic, intermediate and mafic igneous rocks differ in their mineral composition. The latter distinguishes it from gabbro. Is pumice extrusive or intrusive? Diorite (red) on the QAPF diagram. Which of these minerals is commonly found in both mafic and felsic rocks? Mafic rocks have a relatively low silica content and are composed mostly of pyroxenes, olivines and calcic plagioclase. A common mafic rock is basalt. 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. MnO — 0.12 5. Mafic, Felsic, And Intermediate 4. 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. It frequently contains smaller amounts of pyroxene (usually augite but also orthopyroxene), biotite, quartz, olivine, and magnetite. TiO2 — 0.96 PHANERITIC TEXTURE - Igneous rocks with large, visible crystals because therock formed slowly in an underground magma chamber. https://courses.lumenlearning.com/suny-earthscience/chapter/igneous-rocks Ødegården Verk, Norway. Diorite may not be easy to distinguish from similar rocks. Diorite Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar, biotite, hornblende, and/or pyroxene. Gabbro is mafic and darker colored - may be greenish. gabbro. Some diorites contain biotite as well as hornblende, and some contain up to 10% quartz. Sample from Hannukainen, Finland. Lava Fountain And Spatter Cones 9. Mafic and Felsic, some igneous basics. Typical diorite has roughly equally sized black (mostly hornblende) and white (sodic plagioclase) crystals. 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. Slate - Metamorphic. … It sits in the middle of mafic gabbro and felsic granite. Question 1 1 pts Is diorite mafic, felsic, intermediate, or ultramafic in composition? Diorite with tonalite pegmatite. Diorite would have roughly equal amounts of these minerals. Many samples of diorite display a 'salt-and-pepper' texture due to the near-equal mixture of light- and dark-colored minerals. The only igneous rocks on this list are the first two. Composite Cone 11. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. Note, Only igneous rocks are classified as felsic or mafic. 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. 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. 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). 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. It is used as a dimension and building stone, but not very widely because of limited supply. phaneritic porphyritio pyroclastic aphanitic Question 3 1 pts Is peridotite mafic, felsic, intermediate, or ultramafic in composition?

If the molten rock solidifies before the gas has escaped, the bubbles become small rounded or elongated cavities in the rock. 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. (1980). Narvik, Norway. Its vesicular structure makes it light enough to float on water. The flattening of the fragments in the mafic bands suggests that this exposure is in the hinge of a fold. Mafic and felsic dikes that intrude Beehive Diorite recrystallised under amphibolite and then greenschist facies conditions. intermediate mafic felsic granite, rhyolite) (diorite, andesite) (basalt, gabbro (peridotite, etc.) extrusive, felsic porphyritic texture gray/greenish crystals (class sample is distinct red color) Porphyritic Andesite. Diorite - intermediate (half way between mafic and felsic) slate - metamorphic rock that cannot fall into these categories . It thus qualifies as a diorite. Uralite is a name given to secondary hornblende (or actinolite) phenocrysts. Intermediate: refers to igneous rocks where the proportions of light and dark minerals are roughly equal. Rocks: Texture: Obsidian is an easily recognizable igneous rock. schist - metamorphic rock that cannot fall into these categories . Rhyolite is rarely found as lava. Diorite - Felsic. Rhyolite is rarely found as lava. Heat would destroy them. Diorite may contain small amounts of quartz, microcline, and olivine. Diorite and gabbro are different in term of plagioclase species. Additionally, they contain somewhat more gas than do the mafic magmas, but not quite as much as the felsic magmas (see below). Width of sample 9 cm. 4. 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. basalt gabbro diorite granite. Diorite is usually known by the name black granite (it is not the only rock type named so) although geologically they are different rocks. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite. The original pyroxene-plagioclase assemblage has been hydrothermally altered to hornblende-scapolite assemblage. Width of sample 10 cm. 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? PORPHYRITIC TEXTURE - an igneous roc… Best, Myron G. (2002). Conglomerate - Clastic Sedimentary. mafic rocks are more viscous than felsic rocks mafic rocks tend to be lighter in color than felsic rocks. Which of the following igneous rocks crystallizes near the Earth's surface? quartz alkali feldspar plagioclase feldspar olivine 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. Mafic Rock. Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. Sierra Nevada, California. Varieties deficient in hornblende and other dark minerals are called leucodiorite. Diorite was used by both the Inca and Mayan civilizations, but mostly for fortress walls, weaponry, etc. Mafic Rocks and Rhyolite We have granite, which is intrusive felsic, diorite, which is intrusive intermediate, and andesite, which is extrusive intermediate. 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. Width of sample 8 cm. It is an altered andesite (volcanic analogue of diorite and hence has much finer grain size). Rock salt- Chemical Precipitate Sedimentary. Pallavas mamallapuram is a great example of diorite relief sculpture. Accessory minerals include apatite, sphene (titanite), ilmenite, zircon, etc. 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. Obsidian is a natural glass - it lacks crystals, and therefore lacks minerals. 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. A dioritic rock containing feldspathoid mineral/s and no quartz is termed foid-bearing diorite or foid diorite according to content. What rock from the chart is both MAFIC and EXTRUSIVE. Your should be able to successfully complete these tasks when you have finished reviewing the related course resources (e.g., slides, videos, maps). Other Characteristics: found as both lava and pyroclastic tuff. Lava Dome 12. Rhyolite is an extrusive felsic (silicic) volcanic rock. Senja, Norway. mafic 96: - Based on your estimate, describe this rock as felsic, intermediate, mafic, or ultramafic. Diorite is a plutonic igneous rock with intermediate composition between mafic and felsic rocks. Orbicular diorite shows alternating concentric growth bands of plagioclase and amphibole surrounding a nucleus, within a diorite porphyry matrix. Diorite results from the partial melting of a mafic rock above a subduction zone. Kaatiala, Finland. intrusive, intermediate composition, phaneritic texture, tiny black crystals, can be reddish in color **looks like a Dalmatian ... mafic looks like black/dark pumice. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. The classification based on mineralogy, into mafic and felsic, is accepted as the primary scheme of classification for 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. Al2O3 — 16.92 An intermediate example is Diorite. These minerals are high in magnesium and ferric oxides, and their presence gives mafic rock its characteristic dark colour. When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to gabbro. ... Mafic rocks/magmas are _____, whereas felsic rocks/magmas are _____. 1. Fe2O3 — 2.54 Basalt - Mafic. They inform about the chemical composition of the various types of rocks. Aa And Pahoehoe Lava 10. It is visibly crystalline and usually has a granular texture (composed of roughly equally sized crystals) although the appearance may vary widely. a “felsic” light color. Phaneritic Vs Aphanitic 5. Diorite (red) on the QAPF diagram. What type of composition would result in a magma if equal amounts of basaltic and granitic magma were mixed? 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. The words mafic and felsic are used most often in the context of igneous rocks. But you can also find this rock in greenish, bluish grey and black hues.

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