Amphibolite definition, a metamorphic rock composed mainly of amphibole and plagioclase. The archaic term epidiorite is sometimes used, especially in Europe, to refer to a metamorphosed ortho-amphibolite with a protolith of diorite, gabbro or other mafic intrusive rock. A variety of sedimentary, igneous, and metamorphic rocks can be the protolith of hornfels. Physical properties of rocks play an important role in determining its applications in various fields. Metamorphic rocks form from pre-existing rocks ("parent rocks") due to changes in either temperature, pressure, or volatiles within the earth, often by a combination of all three. The metamorphic word comes from Greek and means “to change form”. The word metabasalt was thus coined, largely to avoid the confusion between ortho-amphibolite and para-amphibolite. It forms by regional metamorphism along convergent plate boundaries. Huge collection, amazing choice, 100+ million high quality, affordable RF and RM images. amphibolitic; Translations . Sandstone. Classification of Igneous Rocks: Textures and Composition, Sedimentary Rocks: Definition, Types & Examples, Metamorphism of Rocks: Definition, Process & Influencing Factors, Contact Metamorphism Vs. Related terms . Regional Metamorphism: Definition & Differences, Intrusive Igneous Rock: Definition & Examples, Geological Folds: Definition, Causes & Types, Bowen's Reaction Series: Crystallization Process & Magmatic Differentiation, Detrital & Chemical Sedimentary Rocks: Definition & Differences, Rock Cycle: Igneous, Sedimentary, and Metamorphic Rocks, Unconformities in Geology: Definition & Types, Lithification of Sediments: Definition & Processes, Volcanic vs Plutonic Igneous Rocks: Definition and Differences, Geologic Time Scale: Major Eons, Eras, Periods and Epochs, Geological Faults: Definition, Causes & Types, What is Relative Dating? Different parent-rock compositions produce different kinds of metamorphic rocks. The geology reflected in the remainder of this article comes from the 1911 Encyclopedia Britannica and reflects views from the first decade of the 20th Century. Amphibolite either lacks or has weakly developed foliation. Gneiss. Amphibolite is a type of metamorphic rock that is rich in minerals of the amphibole group, of which the most common mineral is hornblende. The physical properties of Amphibolite depend on its formation. answer! It is easily available and has attractive textures. 3. A contact between amphibolite (on the right) and tonalite pegmatite. All other trademarks and copyrights are the property of their respective owners. The original parent rock (or protolith) of mica schist is shale. The original rock that was metamorphosed is usually referred to as the "parent rock" or "protolith". A holocrystalline plutonic igneous rock composed primarily of hornblende amphibole is called a hornblendite, which is usually a crystal cumulate rock. There are 3 factors that cause an increase in pressure and the formation of metamorphic rock. Amphibolite is a metamorphic rock with large green, black, and brown grains. Deposits containing dolomite and siderite also readily yield amphibolite (tremolite-schist, grunerite-schist, and others) especially where there has been a certain amount of contact metamorphism by adjacent granitic masses. Eskola defined its "amphibolite facies" in a … Hardness and Strength of Amphibolite. Instead it is a rock type that forms when an existing rock is metamorphosed. The process of formation of rocks is different for various rocks. In dry rocks, however, additional heat (and burial) may result in granulite facies conditions. If the amphibolite appears to transgress apparent protolith bedding surfaces it is an ortho-amphibolite, as this suggests it was a dyke. Amphibolite is a gneissose or granofelsic metamorphic rock mainly consisting of green, brown or black amphibole and plagioclase (including albite), which combined form ≥75% of the rock and both of which are present as major constituents; the amphibole constitutes ≥50% of the total mafic constituents and is present in an amount of ≥30%. Without the added pressure the basaltic rock that would be yielded is green schist. More common is to find phenocrysts of pyroxene, olivine, plagioclase and even magmatic amphibole such as pargasite rhombohedra, pseudomorphed by hornblende amphibole. amphibolite (plural amphibolites) Any of a class of metamorphic rock composed mainly of amphibole with some quartz etc. Metamorphic rock forms due to heat and temperature which changes original rock or parent rock into new rock. Gneissic texture may occur nearby, if not then mylonite zones, foliations and ductile behaviour, including stretching lineations may occur. Amphibolite can be defined as a granular metamorphic rock which mainly consist of hornblende and plagioclase. Which rock has the highest metamorphic grade? Historical Views of Amphibolite . The photo in Figure 8.67 is an example. The amphibolite, a metamorphosed black volcanic rock, formed from lavas that spilled on the floor of a shallow sea, mixing with layers of mud, sand, and volcanic ash.. Ecoregions of North Carolina and South Carolina (EPA) The rugged, steeply sloping mountains are composed of Precambrian amphibolite and gneiss.. Ecoregions of North Carolina and South Carolina (EPA) Amphibolites are metamorphic rocks with large grains of green, brown, and black. Media in category "Amphibolite" The following 60 files are in this category, out of 60 total. Besides, it has a reasonable […] Amphibolite Parent Rock: Basalt The rock consists of amphiboles, is generally dark-colored and heavy, with a weakly foliated structure. While not a true metamorphic rock name, as it infers an origin, it is a useful term. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure. Other minerals in tonalite are plagioclase and quartz. Giant pool of igneous rock, often hundreds of kilometers long and tall. From shop BeakersWorld. Amphibolite was a favourite material for the production of adzes (shoe-last-celts) in the central European early Neolithic (Linearbandkeramic and Rössen cultures). Amphibolite definition is - a usually metamorphic rock consisting essentially of amphibole. Amphibolite ( /æmˈfɪbəlaɪt/) is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase. (1999) and Furnes et al. Approx 20 natural gemstone beads. Gneiss is a foliated metamorphic rock made up of granular mineral grains. Senja, Norway. Amphibolite is a coarse-grained metamorphic rock that is composed mainly of green, brown, or black amphibole minerals and plagioclase feldspar. Quartz, magnetite, and calcite can also be present in small amo… Rock … The small flakes of black and white in the rock often give it a salt-and-pepper appearance. Amphibolite need not be derived from metamorphosed mafic rocks. Parent Rocks and Protoliths. Instead it is a rock type that forms when an existing rock is metamorphosed. Picking a sill and thin metamorphosed lava flows may be more troublesome. metamorphic rock composed mainly of … It can also contains other metamorphic minerals such as biotite, epidote, garnet, wollastonite, andalusite, staurolite, kyanite and sillimanite. While it is not impossible to have remnant protolith mineralogy, this is rare. This dark-colored rock is predominantly composed of macroscopic amphibole. Firstly, for an orthoamphibolite or amphibolite to be classed as a metamorphic amphibolite, it must be certain that the amphibole in the rock is a prograde metamorphic product, and not a retrograde metamorphic product. Limestone. See more. Blueschist Parent Rock: Basalt This rock derives its name from its color. Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation. Westboro as portrayed by Nelson (1974), Bell and Alvord (1976), and Hepburn and DiNitto (1978) are correlative [with varying certainty]. All rights reserved. Amphibolite facies conditions are experienced at temperatures in excess of 500 °C and pressures less than 1.2 GPa, well within the ductile deformation field. Amphibolite Metamorphic Rock Measures 1 - 2 Inches on Longest Side - 3 Unpolished Mineral Specimens BeakersWorld. High grade dark-colored hornblende-bearing rock is hornblende gneiss. Amphibolite is a non foliated metamorphic rock that is mainly composed of mineral amphibole and plagioclase feldspar with little or no quartz. Parent Rocks and Protoliths. Among the igneous rocks, amphibolite can form from basalt and gabbro. Conglomerate. Parent Rock of Gneiss. - Science Exam 13 25 Terms. What is the parent rock of MARBLE? Amphibolite is a type of metamorphic rock that is rich in minerals of the amphibole group, of which the most common mineral is hornblende. Schistose rocks with a similar composition are hornblende schists. 5 out of 5 stars (1,412) 1,412 reviews $ 10.99. Amphibolite is a very unfortunate name given to two very different things: a rock type, and a metamorphic facies. Earn Transferable Credit & Get your Degree, Get access to this video and our entire Q&A library. For instance, shale (sedimentary rock) is the parent rock of slate (metamorphic rock). The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. Hornfels is not a rock that is "deposited". The photo in Figure 8.67 is an example. YOU MIGHT ALSO LIKE... Parent Rocks Of Metamorphic Rocks 9 Terms. Further burial and metamorphic compression (but little extra heat) will lead to eclogite facies metamorphism; with more advanced heating the majority of rocks begin melting in excess of 650 to 700 °C in the presence of water. The amphibole are usually the member of the hornblende group. Uralite is a particular hydrothermally altered pyroxenite; during autogenic hydrothermal circulation the primary mineralogy of pyroxene and plagioclase, etc. Para-amphibolite will generally have the same equilibrium mineral assemblage as orthoamphibolite, with more biotite, and may include more quartz, plagioclase, and depending on the protolith, more calcite/aragonite and wollastonite. ... and actinolite break down by dehydration reactions, producing a specific kind of rock called an amphibolite. Jake_Haas250. Mica schist, the most common schistose rock and the second most common metamorphic rock, is composed mostly of mica (usually biotite or muscovite) and smaller amounts of quartz. Amphibolite is a very unfortunate name given to two very different things: a rock type, and a metamorphic facies. Width of sample 10 cm. Large bubbled pool of igneous rock between rock layers. Amphibolite / æ m ˈ f ɪ b ə l aɪ t / is a metamorphic rock that contains amphibole, especially the species hornblende and actinolite, as well as plagioclase.A holocrystalline plutonic igneous rock composed primarily of hornblende amphibole is called a hornblendite, which is usually a crystal cumulate rock.Rocks with >90% amphiboles which have a feldspar groundmass may be a lamprophyre. What is the parent rock of META-CONGLOMERATE? When igneous and metamorphic rock intrusions solidify inside other rocks within the earth’s crust, they form an amphibolite. Laccolith. In the much larger and lower metamorphic grade ISB, amphibolites with relict pillow lava structures were discovered in the late 1960s by the Kryolite company geologists prospecting for iron ore (Keto and Kurki, 1967); subsequent spectacular pillow lava finds were presented by Komiya et al. Amphibolite, a rock composed largely or dominantly of minerals of the amphibole group. Amphibolite: Amphibolites are metamorphic rocks with large grains of green, brown, and black. Create your account. Amphibolite is available in black, brown, green, grey colors. Actinolite schist is often the result of hydrothermal alteration or metasomatism, and thus may not, necessarily, be a good indicator of metamorphic conditions when taken in isolation. Services, Classification of Metamorphic Rocks: Texture & Parent, Working Scholars® Bringing Tuition-Free College to the Community. Metamorphic rocks composed primarily of amphibole, plagioclase, with subordinate epidote, zoisite, chlorite, quartz, titanite, and accessory leucoxene, ilmenite and magnetite which have a protolith of an igneous rock are known as Orthoamphibolite. Westboro Formation consists primarily of orthoquartzite and subordinate mica schist, calc-silicate rock, amphibolite, and quartzitic biotite gneiss and schist. Amphibolite facies equilibrium mineral assemblages of various protolith rock types consist of: Amphibolite facies is usually a product of Barrovian Facies Sequence or advanced Abukuma Facies Sequence metamorphic trajectories. The term has been applied to rocks of either igneous or metamorphic origin. Often, this will take on the crystal form and habit of the original protolith assemblage; actinolite pseudomorphically replacing pyroxene is an indication that the amphibolite may not represent a peak metamorphic grade in the amphibolite facies. What rock is this? cougfan32. Amphibolite is a grouping of rocks composed mainly of amphibole and plagioclase feldspar, with little or no quartz. The parent rock of amphibolite could be basalt or gabbro, which are rocks very similar to amphibolite. Sometimes, amphibolite contains large deposits of the gemstone garnet. As already noted, slate is formed from the low-grade metamorphism of shale, and has microscopic clay and mica crystals that have grown perpendicular to the stress. These rocks are composed of many distinct minerals. In epidiorite the original clinopyroxene (most often augite) has been replaced by the fibrous amphibole uralite. Phyllite could also be considered the parent rock as mica schist is a more highly metamorphosed phyllite. Besides, it has a … They may also contain trace amounts of quartz and other minerals. Sciences, Culinary Arts and Personal The parent rock is sedimentary, igneous, or metamorphic. The original rock that was metamorphosed is usually referred to as the "parent rock" or "protolith". Amphibolite facies is a result of continuing burial and thermal heating after greenschist facies is exceeded. © copyright 2003-2020 Study.com.