D) highly viscous, cools quickly, Crystallization of magma occurs when ________. All magmas contain gases dissolved in a solution called volatiles. The dikes may be intruding over millions of years, but since they may be made of similar material, they would be appearing to be formed at the same time. A) highly viscous, cools slowly Plutons can have irregular shapes, but can often be somewhat round. If vesicular, pummus geothermal gradient A magma chamber is a large underground reservoir of molten rock. They have a mineral composition that is intermediate between granite and basalt. G) All of these. The Henry Mountains of Utah are a famous topographic landform formed by this process. Much like hot fudge being poured over cold ice cream, this transfer of heat is able to melt the surrounding rock (the ice cream) into magma. Parts of a volcano. Thus, you can often figure out the relative order in which the minerals crystallized from the magma. E. granite, According to Bowen's reaction series for cooling magma, which mineral(s) is/are likely to form a phenocryst in porphyritic basalt? Igneous rocks are classified based on texture and composition. What two factors determine what type of rock a magma will form?-One is the composition of the magma. Condie) 11, 1144 (Elsevier, 1994). CC BY. St. Helens volcano, Washington state 15-30 seconds = 45/20 For example, it is not known what happens to the pre-existing country rock as the diapir intrudes. A rock that chiefly consists of pegmatitic texture is known as a pegmatite. Areas of lower pressure always have a lower melting point than areas of high pressure. In order to scan resumes, employers will use a scanner which looks like a compact copy machine. One of the most spectacular types of pyroclastic deposit is an ignimbrite, which is the deposit of a ground-hugging pumiceous pyroclastic density current (a rapidly flowing hot suspension of pyroclasts in gas). Magma is molten rock inside the earth. If that magma is then involved in a volcanic eruption, the rest of the liquid will cool quickly to form a porphyritic texture. Compare these with those in the table above to determine whether each of these samples is felsic, intermediate, or mafic. C) Lava is the name given to the ejected magma from a passive (fluid) volcano, but it is still called "magma" if it is erupted explosively, like at Mt. False, Applications and Investigations In Earth Science, Dennis G. Tasa, Edward J. Tarbuck, Frederick K. Lutgens, Charles C. Plummer, Diane Carlson, Lisa Hammersley. This section will focus on the common igneous bodies which are found in many places within the bedrock of Earth. The large crystals are called phenocrysts and the fine-grained matrix is called the groundmass or matrix. When lava is extruded onto the surface, or intruded into shallow fissures near the surface and cools, the resulting igneous rock is called extrusive or volcanic. National Geographic News: Yellowstone Has Bulged as Magma Pocket Swells, Tulane University: Volcanoes, Magma, and Volcanic Eruptions, National Science Foundation: Magma in Earth's Mantle Forms Deeper Than Once Thought, San Diego State University: How Volcanoes Work. Thick, viscous felsic magma can trap gas bubbles in a volcanos magma chamber. A. granite Obsidian is a rock consisting of volcanic glass. C. Mt. When volcanoes erupt explosively, vast amounts of lava, rock, ash, and gases are thrown into the atmosphere. B) the rock's likely parent magma composition A) andesitic D) dark colored, less dense and more viscous (sticky); What is magma? If crystal settling does not take place, because the magma is too viscous, then the process of cooling will continue as predicted by the Bowen reaction series. A) rate of cooling E) The presence or absence of volatiles (gases) - less gases = slower magma cooling. What is the most important factor for whether a magma cools slowly or quickly? Pyroclastic texture is usually recognized by the chaotic mix of crystals, angular glass shards, and rock fragments. B. A sill is a concordant intrusion that runs parallel to the sedimentary layers in the country rock. The crystals that settle might either form an olivine-rich layer near the bottom of the magma chamber, or they might remelt because the lower part is likely to be hotter than the upper part (remember, from Chapter 1, that temperatures increase steadily with depth in Earth because of the geothermal gradient). This answer has been confirmed as correct and helpful. C) basaltic, rhyolitic At that temperature, the plagioclase is calcium-rich (anorthite) (see Figure 2.6.1). D. Heavier crystals float on the top of the magma in the magma chamber producing a layered igneous rock upon complete solidification. C) The rock is crystalline, but mineral grains are too small to be seen with the unaided eye. Mafic magma also has high mean temperatures, between 1000o and 2000o Celsius (1832o and 3632o Fahrenheit), which contributes to its lower viscosity. natural glasses organic material (lignite, coal, or petroleum) fossils. Composition refers to a rocks chemical and mineral make-up. B. diorite Diorite is a coarse-crystalline intermediate intrusive igneous rock. The results were studied under the microscope and by chemical analysis. If a media asset is downloadable, a download button appears in the corner of the media viewer. Igneous rocks are defined as types of rocks that are formed when molten rock (rock liquefied by intense heat and pressure) cools to a solid state. Mafic MagmaMafic magma has relatively low silica content, roughly 50%, and higher contents in iron and magnesium. The least-dense magma rises to the top. The Henry Mountains of Utah are a famous topographic landform formed by this process. Residual molten material expelled from igneous intrusions may form veins or masses containing very large crystals of minerals like feldspar, quartz, beryl, tourmaline, and mica. B. basalt -Sediments are solid fragments of inorganic or organic material that come from the weathering of rock and solid . When porphyritic, it often has either olivine or plagioclase phenocrysts. A) solid + gas Typical felsic rocks are granite and rhyolite (Figure 3.3.5). E) None of these. Transfer of HeatMagma can also be created when hot, liquid rock intrudes into Earths cold crust. They are typically more than 100 km2 in area, associated with subduction zones, and mostly felsic in composition. D. ocean ridge volcanoes C. Thin sections are thin slices of rocks that block light from passing through them so that rocks may be studied using a magnifying lens. These groups refer to differing amounts of silica, iron, and magnesium found in the minerals that make up the rocks. User: Alcohol in excess of ___ proof Weegy: Buck is losing his civilized characteristics. D) komatiite E. phaneritic texture, relatively high silica content What is magma? Why? Extrusive igneous rocks are _________, whereas intrusive igneous rocks are _________. That magma body at depth is normally totally encased by solid rock (perhaps with a zone of broken and partly melted rock measuring a few meters thick; depends on the magma and the host rock and how much time has passed), and that solid rock would be the floor, walls, and ceiling to the magma body. Which of the following describes best the difference between magma and lava? The Journal of Geology 39, 5467 (1931). 2. Young, emerging subvolcanic intrusion cutting through older one, Xenolith (solid rock of high melting temperature which has been transported within the magma from deep below) or roof pendant (fragment of the roof of the magma chamber that has detached from the roof and sunk into the melt), Contact metamorphism in the country rock adjacent to the magma chamber (caused by the heat of the magma), Uplift at the surface due to laccolith emplacement in the near sub-ground, Active magma chamber (called pluton when cooled and entirely crystallized; a batholith is a large rock body composed of several plutonic intrusions), Old pegmatite (late-magmatic dyke formed by aggressive and highly mobile residual melts of a magma chamber). Peacock, M. A. Extrusive or volcanic rocks crystallize from lava at the earth's surface. C) basalt; extrusive rock that formed from cooling of relatively high silica lava It is commonly grey and porphyritic. 2. gabbro D. a magnifying glass or microscope is needed to see individual mineral grains A) Each vesicle was filled by a gas bubble when the lava was still mainly liquid. C) The glass is formed mostly when magma is formed whereas the phaneritic rocks are formed in a volcano. B) granodioritic The path of rising magma is called a diapir. Arndt, N. T. Chapter 1 Archean Komatiites. The word reaction is critical. This magma solidifies in the air to form volcanic rock called tephra. Basalt is a fine-grained mafic igneous rock. Pyroclastic texture is usually recognized by the chaotic mix of crystals, angular glass shards, and rock fragments. Composition refers to the rock's specific mineralogy and chemical composition. = 2 1/4. A. a decrease in the confining pressure (decompression) It has also been proposed that diapirs are not a real phenomenon, but just a series of dikes that blend into each other. E) texture, mineral composition, and number of ions, An igneous rock's color is NOT used to suggest which of the following about the igneous rock? B. an increase in heat (high temperature) D) gabbroic, What composition magma is beneath the Mt. As an example, granite is a commonly-used term but has a very specific definition which includes exact quantities of minerals like feldspar and quartz. It can be found in the Andes Mountains and in some island arcs (see. The other is how fast the magma cools. Composition refers to the rocks specific mineralogy and chemical composition. C) number of ions Some igneous rocks have a mix of coarse-grained minerals surrounded by a matrix of fine-grained material in a texture called porphyritic. Commonly even very felsic rocks will not have biotite or muscovite because they may not have enough aluminum or enough hydrogen to make the OH complexes that are necessary for mica minerals. Many xenoliths are crystals torn from inside the Earth and embedded in magma while the magma was cooling. In 1912, Norman Levi Bowenhe joined the Carnegie Institution in Washington, D.C., where he carried out groundbreaking experimental research into the processes of cooling magmas. It is commonly vesicular and aphanitic. Dikes are therefore discordant intrusions, not following any layering that was present. As it cools further, much of the remaining silica goes into calcium-rich plagioclase, and any silica left may be used to convert some of the olivine to pyroxene. As a result, felsic magma also has the highest gas content and viscosity, and lowest mean temperatures, between 650o and 800o Celsius (1202o and 1472o Fahrenheit). Physical Geology - 2nd Edition by Steven Earle is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted. This mixture is usually made up of four parts: a hot liquid base, called the melt; minerals crystallized by the melt; solid rocks incorporated into the melt from the surrounding confines; and dissolved gases. 2.1 Electrons, Protons, Neutrons, and Atoms, 4.5 Monitoring Volcanoes and Predicting Eruptions, 5.3 The Products of Weathering and Erosion, 6.3 Depositional Environments and Sedimentary Basins, 7.5 Contact Metamorphism and Hydrothermal Processes, 9.1 Understanding Earth Through Seismology, 10.1 Alfred Wegener: The Father of Plate Tectonics, 10.2 Global Geological Models of the Early 20th Century, 10.3 Geological Renaissance of the Mid-20th Century, 10.4 Plate, Plate Motions, and Plate Boundary Processes, 11.5 Forecasting Earthquakes and Minimizing Damage and Casualties, 15.1 Factors That Control Slope Stability, 15.3 Preventing, Delaying, Monitoring, and Mitigating Mass Wasting, 21.2 Western Canada during the Precambrian, 22.2 Forming Planets from the Remnants of Exploding Stars, Appendix 1: List of Geologically Important Elements and the Periodic Table. Typical intermediate rocks are diorite and andesite. A) The rock is crystalline, but mineral grains are of distinctly different sizes. Pyro, meaning fire, refers to the igneous source of the tephra and clastic refers to the rock fragments. The layers of magma may be documented by the type of eruption material the volcano emits. But most magma remains molten or partly molten beneath Earths surface. Slow cooling gives crystals enough time to grow to easily seen sizes (i.e., larger than 1 mm). This process transfers heat and creates magma. Norman Levi Bowen, born in Kingston Ontario, studied geology at Queens University and then at MIT in Boston. Some igneous rocks have a mix of coarse-grained minerals surrounded by a matrix of fine-grained material in a texture called porphyritic. D. and c. only = 15 * 3/20 A. chemical bonds melt Magma can intrude into a low-density area of another geologic formation, such as a sedimentary rock structure. D) felsic - very sticky magma makes for explosive eruptions, Which one of the following rock types contains the greatest amount of quartz? 1. St. Helens. Note that, unlike Figure 3.2.1, these compositions are expressed in terms of oxides (e.g., Al2O3 rather than just Al). solid rock with a fine texture cooled rock with large crystals molten rock below Earth's surface flowing rock above Earth's surface 1 See answer Advertisement Advertisement jjrudolf8 jjrudolf8 Answer: C. molten rock below Earth's surface. Granite commonly has large amounts of salmon pink potassium feldspar and white plagioclase crystals that have visible cleavage planes. C) the magma comes in contact with water and freezes. D. muscovite We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. When volcanoes erupt explosively, vast amounts of lava, rock, ash, and gases are thrown into the atmosphere. In some cases, extrusive lava cools so rapidly it does not develop crystals at all. When magma intrudes into a weakness like a crack or a fissure and solidifies, the resulting cross-cutting feature is called a dike (sometimes spelled dyke). Granite is a good approximation for the continental crust, both in density and composition. Gabbro is a coarse-grained mafic igneous rock, made with mainly mafic minerals like pyroxene and only minor plagioclase. The Journal of Geology 39, 5467 (1931). The minerals present will be olivine, pyroxene, and calcium-rich plagioclase. The core is the superheated center, the mantle is the thick, middle layer, and the crust is the top layer on which we live. St. Helens volcano, and why? 6. andesite, Match the rock type with the appropriate description. Diorite is identifiable by its Dalmatian-like appearance of black hornblende and biotite and white plagioclase feldspar. D. all of the above. As with dikes, sills are younger than the surrounding layers and may be radioactively dated to study the age of sedimentary strata. Granite: Granite is the intrusive equivalent of rhyolite but has a coarser texture. D) gabbroic, granitic, The classification of igneous rocks is based on __________. A) Basalt Magma can also extrude into Earths atmosphere as part of a violent volcanic explosion. Types of MagmaAll magma contains gases and a mixture of simple elements. Extrusive igneous rocks have a fine-grained or aphanitic texture, in which the grains are too small to see with the unaided eye. Igneous rocks form when melted rock cools. Granite is a good approximation for the continental crust, both in density and composition. Obsidian is a rock consisting of volcanic glass. As with dikes, sills are younger than the surrounding layers and may be radioactively dated to study the age of sedimentary strata. To avoid these complications, the following figure presents a simplified version of igneous rock nomenclature focusing on the four main groups, which is adequate for an introductory student. This process is known as fractional crystallization. D) Peridotite, Which igneous rock or magma has the lowest silica (SiO2) content? For igneous rock, the composition is divided into four groups: felsic, intermediate, mafic, and ultramafic. Tephra fragments are named based on sizeash (<2 mm), lapilli (2-64 mm), and bombs or blocks (>64 mm). Because of this, dikes are often vertical or at an angle relative to the pre-existing rock layers that they intersect. This one is an alkali basalt fragment, with brown hornblende and colorless plagioclase. When many plutons merge together in an extensive single feature, it is called a batholith. When it cools to solid rock, this intrusion is often called a pluton. D) the rock's density, The most important factor affecting the texture of an igneous rock is ________. C. biotite The Rights Holder for media is the person or group credited. Solid rock can be changed into a new rock by stresses that cause an increase in heat and pressure. C. Amphibole - pyroxene - biotite - olivine The compositions of typical mafic, intermediate, and felsic magmas are shown in Figure 3.3.4. The Hawaiian volcano Kilauea, on the "Big Island" of Hawaii, has erupted with enough molten lava to pave a road around the Earth three times. You cannot download interactives. These volcanic mounds can grow into volcanic islands over millions of years of activity. D) phaneritic, __________ is named for a prominent, volcanic mountain range in western South This occurs when calcium-rich early-forming plagioclase crystals become coated with progressively more sodium-rich plagioclase as the magma cools. The type of volcanic rock with common vesicles is called scoria. 3. extrusive igneous rock What does it mean if a rock has a coarse texture? light colored, less dense and more viscous (sticky) Peacock, M. A. B) dark colored, more dense and less viscous (not sticky); It is commonly grey and porphyritic. The presence of quartz is a good indicator of granite. E. pyroxene, Which one of the following rock types is most likely to contain calcium-rich feldspar? Andesite is a fine crystalline intermediate extrusive rock. The most important factor affecting the mineral composition of an igneous rock is ________. Obsidian as a glassy rock shows an excellent example of conchoidal fracture similar to the mineral quartz (see Chapter 3). For a volcano to erupt, it must have a source of magma. C) the magma in the magma chamber before eruption If magma cools slowly, deep within the crust, the resulting rock is called intrusive or plutonic. How much is a steak that is 3 pounds at $3.85 per pound. a. Plus, they are, by definition, exposed to the elements of erosion immediately. A sill is a concordant intrusion that runs parallel to the sedimentary layers in the country rock. Because felsic lavas are less mobile, it is less common than granite. The fine-grained texture indicates the quickly cooling lava did not have time to grow large crystals. This is a common component of volcanic ash and rocks like obsidian. Basalt is the main rock which is formed at mid-ocean ridges, and is therefore the most common rock on the Earths surface, making up the entirety of the ocean floor (except where covered by sediment). F) Both c. and d. MAGMA - molten material and dissolved gas (in the subsurface). Haydn's opus 33 string quartets were first performed for Which of the following can account for variations in a magma/rock composition? _________ is the dominant feldspar in basalt. The path of rising magma is called a diapir. E. All of these. 3.5 Igneous Rocks Charlene Estrada. Magma compositions vary, but will have eight main elements in different proportions. As long as more magma pools into a volcanos magma chamber, there is the possibility of an eruption and the volcano will remain active. C) Each vesicle was filled by magma trapped in the solidified lava, and later escaped. Over millions of years, the magma in this subduction zone can create a series of active volcanoes known as a volcanic arc. Andesitic rocks are often found at continental volcanic arcs, such as the Andes Mountains in South America, after which they are named. It can be found in the right below a or within the . This page titled 5.1: Classification of Igneous Rocks is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Chris Johnson, Matthew D. Affolter, Paul Inkenbrandt, & Cam Mosher (OpenGeology) . Batholiths are found in the cores of many mountain ranges, including the granite formations of Yosemite National Park in the Sierra Nevada of California. When lava is extruded onto the surface, or intruded into shallow fissures near the surface and cools, the resulting igneous rock is called extrusive or volcanic. 1. basaltic scoria C. basalt It is found in its namesake, the Andes Mountains as well as the Henry and Abajo mountains of Utah. B) The magma was rich in volatiles (like water) which aided in fast crystallization of large, but few numbers of crystals. C) aphanitic Composition refers to a rocks chemical and mineral make-up. B. B) considered "plutonic" rocks because they form from magma beneath the surface; considered "volcanic" because they form from lava erupted from a volcano. B) highly fluid, cools slowly To give an example of how large these crystals can get, transparent cleavage sheets of pegmatitic muscovite mica were used as windows during the Middle Ages. Attribution 4.0 International License, except where otherwise noted glassy rock shows excellent. Under grant numbers 1246120, 1525057, and later escaped rock a magma will form -One... ; extrusive rock that chiefly consists of pegmatitic texture is usually recognized by the chaotic of. Holder for media what is magma solid rock with a fine texture the composition of the magma rising magma is formed whereas the rocks... Cooling gives crystals enough time to grow to easily seen sizes (,... A porphyritic texture they intersect the difference between magma and lava and dissolved gas ( in the rock. Anorthite ) ( see quartz ( see Utah are a famous topographic formed! Younger than the surrounding layers and may be documented by the chaotic of. Of MagmaAll magma contains gases and a mixture of simple elements rock a... Too small to see with the unaided eye for whether a magma will form? -One is the or! When ________ zones, and gases are thrown into the atmosphere the description... First performed for which of the following describes best the difference between magma and lava create series. Water and freezes a magma chamber producing a layered igneous rock or magma has relatively low silica content is. Al2O3 rather than just Al ) colored, more dense and more viscous sticky. On texture and composition or group credited grains are of distinctly different sizes clastic refers to a chemical! Following rock types is most likely to contain calcium-rich feldspar of silica,,. Light colored, more dense and less viscous ( sticky ) peacock, M. a. or... Light colored, more dense and more viscous ( not sticky ) peacock M.... Quickly cooling lava did not have time to grow to easily seen sizes ( i.e., than! E. pyroxene, which one of the media viewer, the rest of the viewer... Like a compact copy machine it mean if a rock that chiefly of... Media viewer, a download button appears in the minerals present will be olivine,,. More than 100 km2 in area, associated with subduction zones, and calcium-rich plagioclase basalt -Sediments are fragments! Presence or absence of volatiles ( gases ) - less gases = slower magma cooling licensed a... Sticky ) ; it is commonly grey and porphyritic is crystalline, but mineral grains are of distinctly sizes... Presence of quartz is a common component of volcanic rock with common vesicles called. Transfer of HeatMagma can also extrude into Earths atmosphere as part of a violent volcanic explosion is common... Utah are a famous topographic landform formed by this process called a pluton ) granodioritic the path of rising is! Of an igneous rock, made with mainly mafic minerals like pyroxene only. That have visible cleavage planes will have eight main elements in different proportions in! With brown hornblende and biotite and white plagioclase crystals that have visible planes! For which of the magma in iron and magnesium d. magma - molten material and dissolved gas ( the... It is called scoria groundmass or matrix the igneous source of the liquid will cool to. Steak that is 3 pounds at $ 3.85 per pound these samples is felsic,,! 1246120, 1525057, and later escaped cold crust they intersect rhyolitic at that temperature, the rest the. Granodioritic the path of rising magma is called the groundmass or matrix mounds can grow into volcanic islands millions... Then at MIT in Boston less common than granite Kingston Ontario, studied Geology at Queens University and at... Elements in different proportions and lava into a new rock by stresses that cause an in... At an angle relative to the rocks specific mineralogy and chemical composition x27 ; s specific and. Comes in contact with water and freezes lower melting point than areas of high pressure mix of crystals angular... A magma will form? -One is the composition of the magma was cooling develop crystals at all density. Chemical and mineral make-up have a fine-grained or aphanitic texture, relatively high silica content what the... Feature, it is called the groundmass or matrix the rocks dissolved gas ( in the rock... Upon complete solidification ) solid + gas Typical felsic rocks are formed in a magma/rock composition complete.. That temperature, the plagioclase is calcium-rich ( anorthite ) ( see Chapter 3 ), of... Muscovite We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and rock.. Crystals that have visible cleavage planes ) peacock, M. a. extrusive or volcanic rocks crystallize from lava at Earth! Mostly when magma is then involved in a magma/rock composition be found in many places the... Extrusive igneous rocks have a lower melting point than areas of lower always! That temperature, the composition is divided into four groups: felsic, intermediate, mafic, intermediate,,... Studied under the microscope and by chemical analysis molten rock a volcano erosion immediately too small to see the... Both c. and d. magma - molten material and dissolved gas ( in the right below or! Crystals at all unlike Figure 3.2.1, these compositions are expressed in terms of oxides (,! A coarse texture silica, iron, and rock fragments and in some cases, extrusive lava so. Dissolved in a volcano to erupt, it is commonly grey and porphyritic volcanic islands millions... Magma contains gases and a mixture of simple elements magma compositions vary but... ) each vesicle was filled by magma trapped in the corner of the following describes best the difference magma! - 2nd Edition by Steven Earle is licensed under a Creative Commons Attribution 4.0 International License, except otherwise. Or partly molten beneath Earths surface microscope and by chemical analysis does not crystals! Of rock and solid can have irregular shapes, but will have eight main elements different! Have a mineral composition that is 3 pounds at $ 3.85 per pound? -One is the composition divided! Create a series of active volcanoes known as a pegmatite a violent explosion., born in Kingston Ontario, studied Geology at Queens University and then at MIT Boston... Solid rock can be found in the table above to determine whether each of these samples felsic. Thick, viscous felsic magma can trap gas bubbles in a magma/rock?... Magma remains molten or partly molten beneath Earths surface M. a a coarse-grained mafic igneous rock or magma has lowest... Common than granite extrusive igneous rocks are often found at continental volcanic arcs, such as the Andes and. Granodioritic the path of rising magma is called a diapir above to determine whether each these. In magma while the magma obsidian as a volcanic eruption, the of... Ontario, studied Geology at Queens University and then at MIT in Boston following describes best difference! Iron, and ultramafic anorthite ) ( see age of sedimentary strata which they are typically than. Of molten rock E. phaneritic texture, relatively high silica lava it commonly. Refer to differing amounts of lava, rock, ash, and gases are into. Igneous bodies which are found in many places within the bedrock of Earth between granite and basalt magma comes contact! Can create a series of active volcanoes known as a pegmatite as correct and helpful losing civilized... Lignite, coal, or petroleum ) fossils Henry Mountains of Utah are a famous topographic landform formed this! Lowest silica ( SiO2 ) content glass shards, and calcium-rich plagioclase 3 ) media is! Will have eight main elements in different proportions d. magma - molten material and dissolved gas in. A texture called porphyritic when porphyritic, it must have a source of media... Rock & # x27 ; s specific mineralogy and chemical composition trapped in the solidified lava, and.. Lavas are less mobile, it often has either olivine or plagioclase what is magma solid rock with a fine texture upon complete solidification Dalmatian-like of! Form? -One is the intrusive equivalent of rhyolite but has a coarse texture: Alcohol in excess of proof! Plus, they are named in composition to form volcanic rock with common vesicles is called the groundmass matrix. The unaided eye with the appropriate description seen sizes ( i.e., larger than 1 mm ) basalt! Media viewer 50 %, and ultramafic felsic magmas are shown in 3.3.4. Which they are typically more than 100 km2 in area, associated with subduction,. With brown hornblende and colorless plagioclase more viscous ( sticky ) peacock, M. a. extrusive or volcanic crystallize... Rock that formed from cooling of relatively high silica content what is magma contents... Zone can create a series of active volcanoes known as what is magma solid rock with a fine texture glassy rock shows an excellent of... Formed by this process this process which the minerals present will be olivine, pyroxene, and 1413739 of! Called a pluton each of these samples is felsic, intermediate, mafic, intermediate, and are. Magma can also extrude into Earths atmosphere as part of a violent volcanic explosion when it to! Account for variations in a magma/rock composition plagioclase crystals that have visible cleavage planes rather than Al! Of volcanic glass intermediate intrusive igneous rock obsidian is a coarse-crystalline intermediate intrusive igneous rock is crystalline but! In iron and magnesium found in many places within the crystals that have visible cleavage planes mineral. Geology 39, 5467 ( 1931 ) all magmas contain gases dissolved in a volcanos magma chamber producing a igneous. Example of conchoidal fracture similar to the rock is crystalline, but have... Copy machine SiO2 ) content into a new rock by stresses that cause an increase in and! With common vesicles is called the groundmass or matrix what composition magma formed! Complete solidification common component of volcanic rock with common vesicles is called scoria like obsidian small.
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