Goldschmidt classification From Wikipedia, the free encyclopedianavigation search This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2010) ( Learn how and when to remove this template message)The Goldschmidt classification, [1] developed by Victor Goldschmidt (1888-1947), is a geochemical classification which groups the chemical elements within the Earth according to their preferred host phases into lithophile ( rock -loving), siderophile ( iron -loving), chalcophile ( ore -loving or chalcogen -loving), and atmophile (gas-loving) or volatile (the element, or a compound in which it occurs, is liquid or gaseous at ambient surface conditions). Some elements have affinities to more than one phase. The main affinity is given in the table below and a discussion of each group follows that table.v t e Goldschmidt classification in the periodic table1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18Group →↓ Period1 1 H2 He2 3 Li4 Be5 B6 C7 N8 O9 F10 Ne3 11 Na12 Mg13 Al14 Si15 P16 S17 Cl18 Ar4 19 K20 Ca21 Sc22 Ti23 V24 Cr25 Mn26 Fe27 Co28 Ni29 Cu30 Zn31 Ga32 Ge33 As34 Se35 Br36 Kr5 37 Rb38 Sr39 Y40 Zr41 Nb42 Mo43 Tc44 Ru45 Rh46 Pd47 Ag48 Cd49 In50 Sn51 Sb52 Te53 I54 Xe6 55 Cs56 Ba72 Hf73 Ta74 W75 Re76 Os77 Ir78 Pt79 Au80 Hg81 Tl82 Pb83 Bi84 Po85 At86 Rn7 87 Fr88 Ra104 Rf105 Db106 Sg107 Bh108 Hs109 Mt110 Ds111 Rg112 Cn113 Nh114 Fl115 Mc116 Lv117 Ts118 Og57 La58 Ce59 Pr60 Nd61 Pm62 Sm63 Eu64 Gd65 Tb66 Dy67 Ho68 Er69 Tm70 Yb71 Lu89 Ac90 Th91 Pa92 U93 Np94 Pu95 Am96 Cm97 Bk98 Cf99 Es100 Fm101 Md102 No103 Lr Goldschmidt classification: Lithophile Siderophile Chalcophile Atmophile Synthetic The trace radioactive elements (namely Tc, Pm, Po, At, Rn, Fr, Ra, Ac, Pa, Np, and Pu) are shown as synthetic, because their occurrence in nature is fleeting and is entirely dependent on their long-lived parents Th and U, and they are not very mobile. For instance, polonium's chemistry would predict it to be a chalcophile, but in actuality it tends to occur instead as a lithophile along with its parent uranium. (Even radon, which is a gas, does not usually have time to travel very far from the original uranium source before decaying.) When needed, these elements are typically produced synthetically in nuclear reactors instead of using the tedious and laborious process of extraction from uranium ores. Contents [ hide ]1 Lithophile elements2 Siderophile elements3 Chalcophile elements4 Atmophile elements5 See also6 References7 External links Lithophile elements [ edit]Lithophile elements are those that remain on or close to the surface because they combine readily with oxygen, forming compounds that do not sink into the core. The lithophile elements include: [ citation needed] Al, B, Ba, Be, Br, Ca, Cl, Cr, Cs, F, I, Hf, K, Li, Mg, Na, Nb, O, P, Rb, Sc, Si, Sr, Ta, Th, Ti, U, V, Y, Zr, W and the lanthanides. Lithophile elements mainly consist of the highly reactive metals of the s- and f-blocks. They also include a small number of reactive nonmetals, and the more reactive metals of the d-block such as titanium, zirconium and vanadium. Lithophile derives from "lithos" which means "rock", and "phile" which means "love". Most lithophile elements form very stable ions with an electron configuration of a noble gas (sometimes with additional f-electrons). The few that do not, such as silicon, phosphorus and boron, form extremely strong covalent bonds with oxygen – often involving pi bonding. Their strong affinity for oxygen causes lithophile elements to associate very strongly with silica, forming relatively low-density minerals that thus float to the crust. The more soluble minerals formed by the alkali metals tend to concentrate in seawater or extremely arid regions where they can crystallise. The less soluble lithophile elements are concentrated on ancient continental shields where all soluble minerals have been weathered. Because of their strong affinity for oxygen, most lithophile elements are enriched in the Earth's crust relative to their abundance in the solar system. The most reactive s- and f-block metals, which form either saline or metallic hydrides, are known to be extraordinarily enriched on Earth as a whole relative to their solar abundances. This is because during the earliest stages of the Earth's formation the reaction that controlled the stable form of each chemical element was its ability to form compounds with hydrogen. Under these conditions, the s- and f-block metals were strongly enriched during the formation of the Earth. The most enriched elements are rubidium, strontium and barium, which between them account for over 50 percent by mass of all elements heavier than iron in the Earth's crust. The nonmetallic lithophiles – phosphorus and the halogens – exist on Earth as ionic salts with s-block metals in pegmatites and seawater. With the exception of fluorine, whose hydride forms hydrogen bonds and is therefore of relatively low volatility, these elements have had their concentrations on Earth significantly reduced through escape of volatile hydrides during the Earth's formation. Although they are present in the Earth's crust in concentrations quite close to their solar abundances, phosphorus and the heavier halogens are probably significantly depleted on Earth as a whole relative to their solar abundances. Several transition metals, including chromium, molybdenum, iron and manganese, show both lithophile and siderophile characteristics and can be found in both these two layers. Although these metals form strong bonds with oxygen and are never found in the Earth's crust in the free state, metallic forms of these elements are thought very likely to exist in the core of the earth as relics from when the atmosphere did not contain oxygen. Like the "pure" siderophiles, these elements (except iron) are considerably depleted in the crust relative to their solar abundances. Owing to their strong affinity for oxygen, lithophile metals, although they form the great bulk of the metallic elements in Earth's crust, were never available as free metals before the development of electrolysis. With this development, many lithophile metals are of considerable value as structural metals (magnesium, aluminium, titanium, vanadium) or as reducing agents (sodium, magnesium, calcium). The process of smelting these metals is extremely energy-intensive. With emissions of greenhouse gases suspected of contributing to climate change, the use of these elements as industrial metals is called into question, despite the depletion of rarer and less reactive chalcophile metals leaving few substitutes. The non-metals phosphorus and the halogens were also not known to early chemists, though production of these elements is less difficult than of metallic lithophiles since electrolysis is required only with fluorine. Elemental chlorine is particularly important as an oxidizing agent – usually being made by electrolysis of sodium chloride. Siderophile elements [ edit]See also: Inner core § Composition Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number. The rarest elements in the crust (shown in yellow) are not the heaviest, but are rather the siderophile (iron-loving) elements in the Goldschmidt classification of elements. These have been depleted by being relocated deeper into the Earth's core. Their abundance in meteoroid materials is relatively higher. Additionally, tellurium and selenium have been depleted from the crust due to formation of volatile hydrides. Siderophile (from sideron, "iron", and philia, "love") elements are the high-density transition metals which tend to sink into the core because they dissolve readily in iron either as solid solutions or in the molten state. The siderophile elements include: gold, cobalt, iron, iridium, molybdenum, nickel, osmium, palladium, platinum, rhenium, rhodium, ruthenium, germanium, silver and tungsten. [2]Manganese may also be included in the siderophilic classification by some. [3] [4]Most siderophile elements have practically no affinity whatsoever for oxygen: indeed oxides of gold are thermodynamically unstable with respect to the elements. They form stronger bonds with carbon or sulfur, but even these are not strong enough to separate out with the chalcophile elements. Thus, siderophile elements are bound through metallic bonds with iron in the dense layer of the Earth's core where pressures may be high enough to keep the iron solid. Manganese, iron and molybdenum do form strong bonds with oxygen but in the free state (as they existed on the primitive Earth when free oxygen did not exist) can mix so easily with iron that they do not concentrate in the siliceous crust as do true lithophile elements. However, ores of manganese are found in much the same sites as are those of aluminium and titanium owing to manganese's great reactivity towards oxygen. Because they are so concentrated in the dense core, siderophile elements are known for their rarity in the Earth's crust. Most of them have always been known as precious metals because of this. Iridium is the rarest transition metal occurring within the Earth's crust, with an abundance by mass of less than one part per billion. Mineable deposits of precious metals usually form as a result of the erosion of ultramafic rocks, but are not highly concentrated even compared to their crustal abundances, which are typically several orders of magnitude below their solar abundances. However, because they are concentrated in the mantle and core, siderophile elements are believed to be present in the Earth as a whole (including the core) in something approaching their solar abundances. Chalcophile elements [ edit]The chalcophile elements include: Ag, As, Bi, Cd, Cu, Ga, Ge, Hg, In, Pb, S, Sb, Se, Sn, Te, Tl and Zn. [5]Chalcophile elements are those that remain on or close to the surface because they combine readily with sulfur and/or some other chalcogen other than oxygen, forming compounds which do not sink into the core. Chalcophile elements are those metals and heavier nonmetals that have a low affinity for oxygen and prefer to bond with sulfur as highly insoluble sulfides. Chalcophile derives from Greek khalkós (χαλκός), meaning "ore" (it also meant "bronze" or "copper", but in this case "ore" is the relevant meaning), and is taken to mean "chalcogen-loving" by various sources [ clarification needed]. Because these sulfides are much denser than the silicate minerals formed by lithophile elements, chalcophile elements separated below the lithophiles at the time of the first crystallization of the Earth's crust. This has led to their depletion in the Earth's crust relative to their solar abundances, though because the minerals they form are nonmetallic, this depletion has not reached the levels found with siderophile elements. However, because they formed volatile hydrides on the primitive Earth when the controlling redox reaction was the oxidation or reduction of hydrogen, the less metallic chalcophile elements are strongly depleted on Earth as a whole relative to cosmic abundances. This is most especially true of the chalcogens selenium and tellurium (which formed volatile hydrogen selenide and hydrogen telluride, respectively), which for this reason are among the rarest elements found in the Earth's crust (to illustrate, tellurium is only about as abundant as platinum). The most metallic chalcophile elements (of the copper, zinc and boron groups) may mix to some degree with iron in the Earth's core. They are not likely to be depleted on Earth as a whole relative to their solar abundances since they do not form volatile hydrides. Zinc and gallium are somewhat "lithophile" in nature because they often occur in silicate or related minerals and form quite strong bonds with oxygen. Gallium, notably, is sourced mainly from bauxite, an aluminum hydroxide ore in which gallium ion substitutes for chemically similar aluminum. Although no chalcophile element is of high abundance in the Earth's crust, chalcophile elements constitute the bulk of commercially important metals. This is because, whereas lithophile elements require energy-intensive electrolysis for extraction, chalcophiles can be easily extracted by reduction with coke, and chalcophiles' geochemical concentration – which in extreme cases can exceed 100,000 times average crustal abundance. These greatest enrichments occur in high plateaux like the Tibetan Plateau and the Bolivian altiplano where large quantities of chalcophile elements have been uplifted through plate collisions. A side-effect of this in modern times is that the rarest chalcophiles (like mercury) are so completely exploited that their value as minerals has almost completely disappeared. Atmophile elements [ edit]The atmophile elements are: [ citation needed] H, C, N and the noble gases. Atmophile elements (also called "volatile elements") are defined as those that remain mostly on or above the surface because they are, or occur in, liquids and/or gases at temperatures and pressures found on the surface. The noble gases do not form stable compounds and occur as monatomic gases, while nitrogen, although it does not have a stable configuration for its individual atoms, forms a diatomic molecule so strong that all oxides of nitrogen are thermodynamically unstable with respect to nitrogen and oxygen. Consequently, with the development of free oxygen through photosynthesis, ammonia was oxidised to molecular nitrogen which has come to form four-fifths of the Earth's atmosphere. Carbon is also classed as an atmophile because it forms very strong multiple bonds with oxygen in carbon monoxide (slowly oxidised in the atmosphere) and carbon dioxide. The latter is the fourth-largest constituent of the Earth's atmosphere, while carbon monoxide occurs naturally in volcanoes and has a residence time in the atmosphere of a few months. Hydrogen, which occurs in the compound water, is also classed as an atmophile. Water is classified as a volatile, because most of it is liquid or gas, even though it does exist as a solid compound on the surface. Because all atmophile elements are either gases or form volatile hydrides, atmophile elements are strongly depleted on earth as a whole relative to their solar abundances owing to losses from the atmosphere during the formation of the Earth. The heavier noble gases (krypton, xenon) are the rarest stable elements on Earth. See also [ edit]Abundance of the chemical elements Victor Goldschmidt Goldschmidt Tolerance Factor References [ edit]^ Goldschmidt, Victor (17 March 1937). "The principles of distribution of chemical elements in minerals and rocks. The seventh Hugo Müller Lecture, delivered before the Chemical Society". Journal of the Chemical Society: 655–673. doi: 10.1039/JR9370000655.^ Siderophile element constraints on the origin of the Moon, 2014, Richard J. Walker, Philosophical Transactions A, accessed 1 December 2015.^ Ball, Philip. "Earth scientists iron out their differences". Nature. Macmillan Publishers Limited. Retrieved 5 June 2017.^ Ramanathan, AL. ; Bhattacharya, Prosun; Dittmar, Thorsten; Prasad, B.; Neupane, B. (2010). Management and Sustainable Development of Coastal Zone Environments. Springer Science & Business Media. p. 166. ISBN 9789048130689. Retrieved 5 June 2017.^ Allaby, M. (2013). A dictionary of geology and earth sciences. Oxford University Press. External links [ edit]Mineralogy notes 3W. M. White. Geochemistry. ISBN 978-0470656686; Chapter 7.2Categories: Geochemistry Periodic table 
Definitions &Translations Vocabulary What does COPROLITH mean? Definitions for COPROLITHHere are all the possible meanings and translations of the word COPROLITH. Princeton's Word Net (0.00 / 0 votes)Rate this definition:coprolith, fecalith, faecalith, stercolith (noun)a hard mass of fecal matter Numerology Chaldean Numerology The numerical value of COPROLITH in Chaldean Numerology is: 4Pythagorean Numerology The numerical value of COPROLITH in Pythagorean Numerology is: 8Images & Illustrations of COPROLITHTranslation Find a translation for the COPROLITH definition in other languages: Select another language: Discuss these COPROLITH definitions with the community: Word of the Day Would you like us to send you a FREE new word definition delivered to your inbox daily? Please enter your email address: Subscribe Citation Use the citation below to add this definition to your bibliography: Style: MLA Chicago APA"COPROLITH." Definitions.net. STANDS4 LLC, 2018. Web. 5 Apr. 2018. < https://www.definitions.net/definition/COPROLITH >. Are we missing a good definition for COPROLITH? Don't keep it to yourself... Submit Definition  chemolithoautotroph chemolithoautotrophnavigation search Contents1 English1.1 Etymology1.2 Pronunciation1.3 Noun1.3.1 Related terms English [ edit]Etymology [ edit]chemo- + lithoautotroph Pronunciation [ edit]Audio (US, Northern California)Noun [ edit]chemolithoautotroph ( plural chemolithoautotrophs) ( biology) A chemoautotroph or lithoautotroph Related terms [ edit]chemolithoautotrophicchemolithoautotrophy Categories: English words prefixed with chemo- English terms with audio links English lemmas English nouns English countable nouns en: Biology  Ethos - Sealing Stone Marble, Granite, Limestone, Slate, Granite and Travertine Polishing and Restoration - London Metamorphic rock Metamorphic rock is one of the three main groups in the rock cycle and includes popular building and flooring stones such as marble and Slate. Metamorphic rock is formed by the changing of a pre-existing rock, known as a protolith, into a new rock. The protolith, meaning 'first stone' in greek, can be igneous, sedimentary or another metamorphic rock. These changes happen without melting which is a characteristic of igneous rock formation. Its name derives from the greek 'metamorphosis' meaning 'change in form'. There are three main processes that can create metamorphic rock: High heat and pressure due to the rock being deep below the Earth's surface Friction and distortion created by tectonic plate movements Intrusion of magma which subjects the rock to high heat Particle sizes in the rock change size during the metamorphism in a process called recrystallisation. High temperatures cause atoms in the crystals to migrate meaning they can re-organise and create new minerals. Differing crystal growths and the type of pressure which is applied will create two possible visual textures, foliated and non-foliated: Foliated: Certain mineral crystals have a tendency to grow perpendicular to the level of stress or pressure applied to them. In this case the rock will become foliated if a strong one directional force is present during recrystallisation. Non-Foliated: When the pressure applied to a recrystallising rock is uniform or if the mineral crystals do not have distinctive growth patterns, the texture of the metamorphic rock will be non-foliated. Slate, probably the most well known foliated rock, originates from the sedimentary rock shale. The growth of calcite crystals under high heat and pressure causes Limestone to become the non-foliated rock, Marble Quartz crystals grow during the metamorphism of Sandstone resulting in the formation of the non-foliated rock, Quartzite. Resourse Box This article is property of Ethos Marble Care UK Ltd – The professional stone restoration company based in London. For more information on all aspects of stone restoration, cleaning, polishing, maintenance and repair, visit our website http://www.ethosmarblecare.co.uk You are welcome to copy and use this article as long as the following conditions are met: The article must be reproduced in its entirety, completely unchanged and without any links removed or added. The resource box at the bottom of the article must be included, unchanged and with the links active. You agree that Ethos Marble Care Uk Ltd is the owner and exclusive copyright holder of the article  Geology batholith Batholiths are complex intrusive bodies composed of plutonic igneous rocks, usually of felsic or intermediate rock-types, such as granite, quartz monzonite, or diorite. Batholiths are also called granite domes. The exposed surface area is defined (by geographers) as more than 100 square kilometers, though large geological batholiths may have less exposure. Areas smaller than 100 square kilometers are called stocks. The entire batholithic emplacement is typically so large that the bases are rarely exposed, and batholiths have steeply inclined walls that form prominent dome structures when exposed by erosive removal of initially overlying rocks. Sometimes batholiths arise through several smaller diapiric intrusions ( plutons) and have a complex history of magmatic intrusion and crystallization at depths of 5 to 30 kilometers. Batholith formation is commonly associated with lithospheric plate boundaries, where tectonic interactions between plates are associated with large scale melting of crustal rocks and the formation of deep magma chambers. As erosion uncovers the crystalline rock that formed at great depth, crystal structures respond to the decrease in load and expand, rendering the plutonic rocks susceptible to exfoliative weathering. Spheroidal weathering produces boulder fields, and sheet-like exfoliative weathering, which is accelerated by frost wedging, creates smooth structures like Half Dome in the 40,000 sq km Sierra Nevada Batholith in Yosemite (upper left, right - click to enlarge). The Coastal Plutonic Complex of British Columbia and Alaska is even larger, extending for 1,800 kilometers and covering 182,500 sq km. Other North American batholiths include the following: The Idaho Batholith is a composite mass of granitic plutons covering approximately 15,400 square miles in central Idaho [ map, Castle Peak, Contact Batholith ]. Guichon batholith in British Columbia contains several large, low-grade copper deposits. The South Mountain Batholith (SMB) of southwestern Nova Scotia is the largest granite batholith in the Appalachian Orogen with an approximate area of 7300 sq km. The Cornubian Batholith was intruded into south-west England at the close of the Variscan Orogeny (late Carboniferous - Permian). [images: photos: Baja Batholith spheroidal weathering, Boulder Batholith & spheroidal weathering, Conrnubian batholith Cligga Head, Enchanted Rock batholith & tree at summit, Golden Horn Batholith, Rocky Mtn. Nat Park, Yosemite batholith, batholith, outcrop Granite Mountain; websites: Avalonia, Halifax Pluton, Boulder Batholith, Cornubian Batholith, Peninsular Ranges batholith, Sierra Nevada Batholith & lithography; lithography: conness contact, Enchanted Rock granite, 2, Julianehåb batholith granite, gallery, mingling of microdioritic and granodioritic magmas in the calc-alkaline Pataz Batholith of the northern Peruvian Cordillera Oriental, schlieren banding in the Sausfjellet pluton, rock gallery including Vioolsdrif Batholith; maps: Boulder Creek Batholith, Cornubian Batholith, Enchanted Rock Batholith, Halifax Pluton, Idaho batholith ecoregions, Verkhisetsk batholith, batholiths in Wisconsin; diagram: plutons and volcanic landforms Labels: batholith, crystalline, diapir, emplacement, exfoliative weathering, felsic, Halifax Pluton, intrusion, stock0 GUIDE<< Homeposted11/24/2007at 11/24/2007 04:09:00 AM  What Are the Elements in the Lithosphere? Science Earth Science Atmosphere Q: What Are the Elements in the Lithosphere? A: Quick Answer The eight commonly occurring elements that are found in Earth's lithosphere include oxygen, silicon, calcium, sodium, magnesium, aluminum, potassium and iron. The crust, which forms part of the lithosphere, contains around 80 chemical elements that are present in varying amounts in approximately 2,000 minerals and compounds. Continue Reading Keep Learning What Elements Make up Earth's Crust? What Are Moon Rocks Made Of? What Are the Five Elements Found in Nature? Full Answer Earth is stratified based on two criteria: chemical constitution and degree of rigidity. The planet has three compositional layers and five mechanical layers. The compositional layers include the crust, mantle and core. The lithosphere, asthenosphere, mesosphere, outer core and inner core comprise the mechanical layers. The lithosphere pertains to the rigid, uppermost mechanical layer, which consists of the crust and topmost portion of the mantle. Its average thickness is measured at around 62 miles. The lithosphere is broken into massive continental and oceanic plates that are constantly sliding, gliding and grinding against each other. The variety of minerals and rocky materials that form on these plates are the products of geological processes. Some of the most abundant minerals found on the crust include quartz, hematite and orthoclase. Quartz is composed of silicon and oxygen; hematite is made up of iron and oxygen; and orthoclase is a potassium aluminum silicate compound. The chemical combination of one or more minerals produce rocks. The general elemental composition of rocks mainly include silicon, oxygen, aluminum, calcium, potassium and sodium. Other elements present in crustal rocks in minute amounts include titanium and hydrogen. Learn more about Atmosphere Sources: cnx.org Related Questions Q: What Is the Earth's Lower Mantle Made Of? A: Earth's lower mantle is made up of mantle-crust that consists of aluminum, silicon, magnesium, calcium, oxygen and iron. These elements in the lower mantle... Full Answer >Filed Under: Layers of the Earth Q: How Can One Identify the Layers of the Earth by Their Chemical Composition? A: Earth's solid mass is composed of iron, oxygen, silicon, magnesium, sulfur, nickel, calcium and aluminum. These materials, according to Learner.org, are sp... Full Answer >Filed Under: Layers of the Earth Q: What Is the Moon Made Of? A: The lunar crust is made of 43 percent oxygen, 20 percent silicon, 19 percent magnesium, 10 percent iron, 3 percent calcium and 3 percent aluminum. The moon... Full Answer >Filed Under: Our Moon Q: Which Layer of the Earth Has the Greatest Mass? A: The layer on Earth with the most mass in the mantle, which is made up of silicate compounds, iron, silicon, magnesium, oxygen and aluminum. The mantle is a... Full Answer >Filed Under: Earth Science You May Also Like Q: Why Is the Atmosphere Important? Q: What Is the Air Pressure in the Exosphere? Q: What Are the Four Elements of Shakespeare's Revenge Tragedy? Q: How Many Elements Are There? Q: What Are the Key Elements of a Clever Campaign Slogan? Q: How Do You Determine Air Changes Per Hour?  Anorthosite Fest Anorthosite Fest Through a Global Forum initiative at Brown University, Professor Lew Ashwal from Witwatersrand University in South Africa visited the Department of Geological Sciences from July 16 to 27th. The overall goal of the Forum was to initiate long-term research links with prominent universities around the globe. Lew is a world expert on terrestrial anorthosite formation and his visit sparked broad interest and support across Brown/MIT NLSI for discussions on the formation of lunar anorthosite. During Lew’s visit, the current knowledge of the origin of both terrestrial and lunar anorthosites was reviewed and interdisciplinary research directions discussed. Lew Ashwal greeting an old friend. Credit: Brown/MITLew’s visit began with two extended lectures by him on terrestrial anorthosites, followed by a three-day field trip to anorthosite regions in the Adirondacks. This was to bring participants up to speed on the current state of knowledge about terrestrial anorthosites and lay the foundation for comparing to lunar anorthosites. Jim Mc Lelland (Colgate University) led the field trip and lectured on the formation of the Adirondack massif. A few additional photos of the field trip are posted on facebook. The field trip was followed by a one-day symposium in which both graduate students and faculty focused on the current state of knowledge about lunar anorthosite formation. The formal symposium drew to a close with the final talk given by Prof. Ashwal, summarizing terrestrial anorthosites and making connections to their lunar brethren. Several young scientists and students on the trail to anorthosites. Credit: Brown-MITThe symposium discussion was very lively and subjects ranged widely from detailed petrology of samples to global dynamics of magma oceans. The consensus among participants was that the new compositional data from remote analysis of lunar mineralogy is most consistent with a global magma ocean (as opposed to serial plutonism). A few people raised questions about how the new-found H2O in the lunar mantle would change our models of anorthosite formation. Also, the issue of how the very pure anorthosite (with scarce mafic minerals) widely observed across the Moon is formed was also discussed. In comparing the lunar anorthosites to terrestrial examples, it was unclear whether they were analogous to Archean anorthosites, which have similarly high An contents, but are thought to be derived from hydrous magmas. Or whether the Proterozoic anorthosite massifs are better analogs for lunar magma ocean evolution, despite having substantially lower An contents. One conclusion was that more experimental work is necessary to quantify fractionation of basaltic liquids at depth, with varying amounts of H2O as well as additional work to identify the type and scale of petrographic relations of other lithologies found with anorthosite across the lunar surface.“The combination of activities provided a highly productive environment that stimulated thought-provoking interactions among Faculty, students, and visitors about the interconnections of fundamental processes that are common to the Earth and the Moon. Was also great fun!” Said NLSI Team lead Dr. Carle Pieters. Posted by: Soderman/NLSI Staff Source: NLSI Team/Brown-MIT  Definitions &Translations Wiktionary (0.00 / 0 votes)Rate this definition:felsic (Adjective)Enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Freebase (0.00 / 0 votes)Rate this definition: Felsic In geology felsic refers to igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron. It refers to those rocks rich in silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. They are usually light in color and have specific gravities less than 3. The most common felsic rock is granite. Common felsic minerals include quartz, muscovite, orthoclase, and the sodium-rich plagioclase feldspars. In terms of chemistry, felsic minerals and rocks are on the other end of the elemental spectrum from the mafic minerals and rocks. In modern usage, the term acid rock, although sometimes used as a synonym, refers to a high-silica-content volcanic rock, such as rhyolite. The term was used more broadly in older geologic literature. It is considered archaic now, as the terms "acidic" and "basic rock" were based on an incorrect idea, dating from the 19th century, that silicic acid was the chief form of silicon occurring in rocks. The term "felsic" combines the words "feldspar" and "silica". The similarity of the term felsic to the German words Fels, meaning "rock", and felsig, meaning "rocky", is purely accidental, as feldspar is a borrowing from German Feldspat, which derives from German Feld, meaning "field". Numerology Chaldean Numerology The numerical value of felsic in Chaldean Numerology is: 5Pythagorean Numerology The numerical value of felsic in Pythagorean Numerology is: 9Images & Illustrations of felsic  lithosphere lithospherelith·o·sphere Use lithosphere in a sentence A spectacular portion of the Earth's lithosphere. Licensed from i Stock Photonoun Lithosphere is defined as the rock and crust surface that covers the Earth. An example of lithosphere is the Rocky Mountain range in western North America. Your Dictionary definition and usage example. Copyright © 2018 by Love To Know Corp Link/Citelithospherethe solid, rocky part of the earth; earth's crust Origin of lithospherelitho- + -sphere Webster's New World College Dictionary, Fifth Edition Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Link/Citelithospherenoun The outer part of the earth, consisting of the crust and upper mantle, about 100 kilometers (62 miles) thick. THE AMERICAN HERITAGE® DICTIONARY OF THE ENGLISH LANGUAGE, FIFTH EDITION by the Editors of the American Heritage Dictionaries. Copyright © 2016, 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Link/Citelithosphere Noun ( plural lithospheres) (geology) The rigid, mechanically strong, outer layer of the Earth; divided into twelve major plates Origin From litho- +"Ž -sphere English Wiktionary. Available under CC-BY-SA license. Link/Cite  Definitions &Translations Wiktionary (0.00 / 0 votes)Rate this definition:phlebolith (Noun)A calcareous deposit in a venous wall or thrombus. Webster Dictionary (0.00 / 0 votes)Rate this definition: Phlebolith (noun)a small calcareous concretion formed in a vein; a vein stone Origin: [Gr. , , a vein + -lite, -lith. ]Freebase (5.00 / 1 vote)Rate this definition: Phlebolith A phlebolith is a small local, usually rounded, calcification within a vein. These are very common in the veins of the lower part of the pelvis, and they are generally of no clinical importance. When located in the pelvis they are sometimes difficult to differentiate from ureteral stones in the ureters on X-ray. Phleboliths in the pelvic region are present in about 44.2% of people and are more commons in females than males. The amount of phleboliths increases with age and they also appear more often on the left than on the right side of the pelvic region. Phleboliths outside the pelvic region appear in about 2% of the population. Phleboliths can be diagnostic for hemangiomas on ultrasound. Numerology Chaldean Numerology The numerical value of phlebolith in Chaldean Numerology is: 7Pythagorean Numerology The numerical value of phlebolith in Pythagorean Numerology is: 8Images & Illustrations of phlebolith Translations for phlebolith From our Multilingual Translation Dictionary Phlebolith Germanphlebolith Hindiflebolith Polishphlebolith Swedish Get even more translations for phlebolith »Translation Find a translation for the phlebolith definition in other languages: Select another language: Discuss these phlebolith definitions with the community: Word of the Day Would you like us to send you a FREE new word definition delivered to your inbox daily? Please enter your email address: Subscribe Citation Use the citation below to add this definition to your bibliography: Style: MLA Chicago APA"phlebolith." Definitions.net. STANDS4 LLC, 2018. Web. 7 Apr. 2018. < https://www.definitions.net/definition/phlebolith >. Are we missing a good definition for phlebolith? Don't keep it to yourself... Submit Definition  Geological Terms Beginning With "U" Home » Geology Dictionary Geological Terms Beginning With "U"For terms beginning with other letters, please click below A B C D E F G H I J K L M N O P Q R S T U V W X Y ZUbiquitous Found everywhere, constantly encountered. Some geologists say that the minerals quartz, calcite, and pyrite are ubiquitous. Ultrabasic Rock An igneous rock with a very low silica content and rich in minerals such as hypersthene, augite, and olivine. These rocks are also known as ultramafic rocks. Examples include: peridotite, kimberlite, lamprophyre, lamproite, dunite, and komatiite. Shown in the photo is a specimen of peridotite. Ultramafic Rock An igneous rock with a very low silica content and rich in minerals such as hypersthene, augite, and olivine. These rocks are also known as ultrabasic rocks. Examples include: peridotite, kimberlite, lamprophyre, lamproite, dunite, and komatiite. Shown in the photo is a specimen of peridotite. Unakite A granite that contains significant amounts of epidote. It typically has a green-and-pink appearance, revealing the epidote and orthoclase feldspar in its composition. Named after the Unaka Mountains of eastern Tennessee. Unassociated Gas Natural gas that is found in a reservoir that does not also contain an accumulation of crude oil. Contrast with associated gas. Unconfined Aquifer An aquifer that is not overlain by an impermeable confining unit and has a porous connection to the atmosphere through which it can receive recharge. In the image at left, the well on the right penetrates an unconfined aquifer. The water level in the well is the same as the water level in the surrounding aquifer. Unconformity A contact between two rock units of significantly different ages. An unconformity is a gap in the time record for that location. Shown in the photo is a section of "The Great Unconformity" of the Grand Canyon. Unconsolidated A term used when referring to sediment that has not been compacted, cemented, and lithified into a rock. The photo shows layers of sand and gravel in an unconsolidated alluvial deposit in North Dakota. Dictionary of Geological Terms - Only $18.95 All scientific disciplines have an essential vocabulary that students and professionals must understand to learn and communicate effectively. A geology dictionary that is used regularly is one of the most important tools for developing professional competence. A good dictionary should be on the desk of every geologist and within easy reach. This dictionary is compact and inexpensive at only $18.95. More information. Unconventional Oil and Gas Crude oil and natural gas that do not readily flow into a drilled well because the rock units in which they are contained either lack the porosity and permeability to allow the oil and gas to flow, or, the oil and gas are adsorbed onto or bound within the grains of the rock . Unconventional oil and gas are produced from shale, tight sands, and coal beds, where liberating the oil and gas from the rock and moving it to the well are the challenges. These rock units must be stimulated by techniques such as hydraulic fracturing, horizontal drilling, steam flooding, injection of water, injection of carbon dioxide, or pressure reduction. Unconventional oil and gas and conventional oil and gas do not differ in their chemical composition. They differ in the type of rock unit from which they are produced. Compare to "conventional oil and gas. "Underclay A name used for a layer of shale or claystone that underlies a coal seam. "Seat rock" and "seat earth" are also used. In some instances, an underclay with a high kaolinite content will be a refractory material, or a "fire clay," that can be used in the manufacture of ceramic products. Uniformitarianism A basic geologic principle. Processes that act upon the Earth today are the same processes that have acted upon it in the past. "The present is the key to the past." Shown in the photo is James Hutton's unconformity at Jedburgh, which he used as an example of the principle of uniformitarianism. Unit Cell The smallest sample of a substance that has a complete representation of its atomic structure. A crystal structure is formed by repetition of the unit cell in three dimensions. The image shows a unit cell of the mineral halite (Na Cl). Uplift A structurally high area of Earth's crust. Formed by movements that bend the crust into a structure such as a dome or an arch. A structurally high area can also be caused by subsidence of adjacent lands. Shown in the image is the Black Hills Uplift which is bounded on one side by the Powder River Basin and on the other by the Williston Basin. Upwelling Movement of cold water from the floor of a lake or ocean up into a shallow area. U-Shaped Valley A deep valley with a flat floor and very steep walls. Shaped in cross section like the letter "U." Valleys with this geometry are frequently cut by a glacier. In the photo is Mc Donald Valley, cut by a glacier and located in Glacier National Park, Montana. A B C D E F G H I J K L M N O P Q R S T U V W X Y ZMore General Geology What Does a Geologist Do? Land Below Sea Level Divisions of Geologic Time Minerals Waterproof Paper Plate Tectonics What Is Earth Science? Rocks More From Geology.com: Geology.com News contains news about geology and earth science from around the world. Rock Gallery: Photos of igneous, sedimentary and metamorphic rocks. Minerals: Information about ore minerals, gem materials and rock-forming minerals. Dacite - a light-colored extrusive igneous rock intermediate between rhyolite and andesite. Gemstones - Colorful images and articles about diamonds and colored stones. Volcanoes - Articles about volcanoes, volcanic hazards and eruptions past and present. Green Diamonds - one of rarest and most valuable diamond colors. Diamonds: Learn about the properties of diamond, its many uses and diamond discoveries.  . The mineral constituents of foliated metamorphic rocks are oriented in a parallel or suhparallel arrangement. Foliated metamorphic rocks are generally associated with regional metamorphism. Four kinds of foliated textures arc recognized. In order of increasing metamorphic grade, these are slaty, phyllitic, schistose and gneissic. Slaty Texture - This texture is caused by the parallel orientation of microscopic grains. The name for the rock with this texture is slate, and the rock is characterized by a tendency to separate along parallel planes. This feature is a property known as slaty cleavage. (Slaty cleavage or rock cleavage is not to be confused with cleavage in a mineral, which is related to the internal atomic structure of the mineral. )Phyllitic Texture - This texture is formed by the parallel arrangement of platy minerals, usually micas, that are barely macroscopic (visible to the naked eye). The parallelism is often silky, or crenulated. The predominance of micaceous minerals imparts a sheen to the hand specimens. A rock with a phyllitic texture is called a phyllite. Schistose Texture This is a foliated texture resulting from the suhparallel to parallel orientation of platy minerals such as chlorite or micas. Other common minerals present are quartz and amphiholes. A schistose texture lies between the parallel platy appearance of phyllite and the distinct banding of gneissic texture. The average grain size of the minerals is generally smaller than in a gneiss. A rock with schistose texture is called a schist Gneissic Texture This is a coarsely foliated texture in which the minerals have been segregated into discontinuous hands, each of which is dominated by one or two minerals. These bands range in thickness from 1 mm to several centimeters. The individual mineral grains are macroscopic and impart a striped appearance to a hand specimen. Light-colored bands commonly contain quartz and feldspar. and the dark hands are commonly composed of hornblende and hiotite. Accessory minerals are common and are useful in applying specific names to these rocks. A rock with a gneissic texture is called a gneiss.  Ophiolite suites Ophiolite suites Since the late 1970s, the term ophiolite has been used to describe sections of oceanic crust and upper mantle, along with sedimentary rocks deposited on the sea floor, emplaced as thrust slices onto continental lithosphere . This process, called obduction, results from continent-continent collision following subduction of oceanic crust and the closure of oceans or back-arc basins. A typical ophiolite suite comprises (from base to top): Harzburgite, dunite, peridotite, and pyroxenite (ultramafic igneous rocks composed of varying amounts of olivine and pyroxene) representing upper, oceanic mantle. They are commonly altered to the slippery, shiny green-black rock serpentinite. Serpentinite is named after its resemblance to the skin of a snake. Indeed, the word ophiolite is derived from the Greek words ophis, meaning snake, and lithos, meaning stone, because of the presence of serpentinites. Iron-titanium and magnesium gabbros. Layered, cumulate-textured gabbros dominate the basal section of oceanic crust. Higher-level gabbros tend to be more massive and associated with plagiogranites. Sheeted mafic dykes, feeders to overlying volcanics. Pillow basalts, formed as lava flows on the sea floor. The characteristic pillow shapes result from rapid cooling when lava contacts seawater. Radiolarian chert and limestone , graywacke and mud-stone or their metamorphic equivalents marble , quartzite and mica schist. Oceanic crust in ophiolites is produced at spreading centers, above zones of subduction in extensional or transtensional arcs (supra-subduction zone ophiolites), and along some leaky transform faults . Ophiolites that lack ultramafic, upper mantle rocks may represent obducted slices of seamounts or oceanic plateaus. Many ophiolites have undergone high pressure-low temperature , blueschist metamorphism in subduction zones prior to their emplacement. Blueschists are named after blue-colored glaucophane and other sodium-rich amphiboles formed in rocks of appropriate composition. Eclogite facies metamophism occurs when rocks are subducted to greater depth. In eclogites, pyroxene, olivine, and plagioclase recrystallize to sodium-rich pyroxene and garnet. During collision, blueschists plus or minus eclogites are thrust as a series of imbricate slices onto lower-grade, continental rocks. Ophiolites may be overprinted by greenschist facies metamorphic assemblages and exhumed during collapse of a thrust-thickened orogen. Ophiolites in orogenic (mountain building) belts represent sutures between two continental plates. Their recognition is therefore important in tectonic reconstructions. Ophiolites host a range of mineral deposits. Ultramafic and gabbroic rocks may contain deposits of chromium or platinum-group elements. Chrysotile asbestos occurs in serpentinites. Copper, zinc, cobalt and nickel sulfides (marine exhalatives) may occur in economic amounts. Some ophiolites host shear controlled epithermal or mesothermal gold mineralization. See also Plate tectonics; Subduction zone  . Facies Eolianite carbonate facies (Holocene) on Long Island, Bahamas. In geology, a facies (pronounced variously as, or ['faysheez', 'fayseez' or 'fash-eez']; plural also 'facies') is a body of rock with specified characteristics, [1] which can be any observable attribute of rocks such as their overall appearance, composition, or condition of formation, and the changes that may occur in those attributes over a geographic area. It is the sum total characteristics of a rock including its chemical, physical, and biological features that distinguishes it from adjacent rock. [2]The term facies was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy, [3] which replaced the earlier notions of Neptunism. Types of facies Sedimentary facies Middle Triassic marginal marine siltstone and sandstone facies exposed in southern Utah. Ideally, a sedimentary facies is a distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment. Sedimentary facies are either descriptive or interpretative. Sedimentary facies are bodies of sediment that are recognizably distinct from adjacent sediments that resulted from different depositional environments. Generally, geologists distinguish facies by the aspect of the rock or sediment being studied. Facies based on petrological characters (such as grain size and mineralogy) are called lithofacies, whereas facies based on fossil content are called biofacies. A facies is usually further subdivided, for example, one might refer to a "tan, cross-bedded oolitic limestone facies" or a " shale facies". The characteristics of the rock unit come from the depositional environment and from the original composition. Sedimentary facies reflect their depositional environment, each facies being a distinct kind of sediment for that area or environment. Since its inception, the facies concept has been extended to related geological concepts. For example, characteristic associations of organic microfossils, and particulate organic material, in rocks or sediments, are called palynofacies. Discrete seismic units are similarly referred to as seismic facies. Walther's Law of Facies Stratigraphic column on the north shore of Isfjord in Svalbard Norway. The vertical succession of rock types (representing sedimentary facies) reflects lateral changes in paleoenvironment. Walther's Law of Facies, or simply Walther's Law, named after the geologist Johannes Walther (1860-1937), states that the vertical succession of facies reflects lateral changes in environment. Conversely, it states that when a depositional environment "migrates" laterally, sediments of one depositional environment come to lie on top of another. [4] In Russia the law is known as Golovkinsky-Walther's Law, honoring also Nikolai A. Golovkinsky [5] (1834-1897). A classic example of this law is the vertical stratigraphic succession that typifies marine transgressions and regressions. Metamorphic facies The sequence of minerals that develop during progressive metamorphism (that is, metamorphism at progressively higher temperatures and/or pressures) define a facies series. Seismic facies Seismic facies are mappable three-dimensional seismic units composed of reflection units whose parameters differ from adjacent facies units. See also Lithofacies Metamorphic rock Sequence stratigraphy Stratum References The Wikibook Historical Geology has a page on the topic of: Walther's principle Reading, H. G. (1996). Sedimentary Environments and Facies. Blackwell Scientific Publications. ISBN 0-632-03627-3. Parker, Sybil P. (1984). Mc Graw-Hill Concise Encyclopedia of Science and Technology. Mc Graw-Hill. p. 705. ISBN 0-07-045482-5. Cross, T. A.; Homewood, P. W. (1997). "Amanz Gressly's role in founding modern stratigraphy". Geological Society of America Bulletin. Geological Society of America. 109 (12): 1617–1630. doi: 10.1130/0016-7606 (1997)1091617:agsrif>2.3.co;2. Stanley, Steven M. (1999). Earth System History. New York: W. H. Freeman and Company. p. 134. ISBN 0-7167-2882-6. Nurgalieva, N. G.; Vinokurov, V. M.; Nurgaliev, D. K. (2007). "The Golovkinsky strata formation model, basic facies law and sequence stratigraphy concept: Historical sources and relations". Russian Journal of Earth Sciences. 9. doi: 10.2205/2007ES000222. The fundamentals of the facies law, known in the West as Walther's Law and in Russia as Golovkinsky-Walther's Law, were also described in Golovkinsky's work long before Walther drew his conclusions on this subject. The present paper shows that the fundamentals of sequence stratigraphy were first set forth in the work of N. A. Golovkinsky. Continue Reading...  Strange Love: 10 Words for Passionate People Words at Play Strange Love: 10 Words for Passionate People What do you call someone who reallyloves cats? Or cheese? Pyrophile Definition:one enthusiastic over fire or fireworks About the Word: The prefix pyro- has an ancestor in the Greek pyr meaning "fire". Pyro- appears in dozens of terms, ranging from pyrotechnics (fireworks) to pyromania (an irresistible impulse to start fires).1/10Oenophile Definition:lover or connoisseur of wine About the Word: If oenophile - from the Greek oinos ("wine") + phile ("lover") - sounds too precious, alternatives include "wine wonk. "By the way, sommelier - the title of the wine steward at a restaurant - has humble origins. It comes from the Old French for "pack animal driver. "2/10Turophile Definition:a lover of cheese; a cheese fancier About the Word: This term - probably coined by an American radio host in 1938 - is far less commonly used than oenophile. Still, someone who passionately enjoys wine and cheese might be described as an oenophile turophile.3/10Xenophile Definition:one attracted to foreign things (as manners, styles, or food)About the Word: The Greek xenos means a stranger or guest; xenophobia ("fear of strangers") is more familiar than xenophilia. However, xenophile makes an appearance in J. K. Rowling's Harry Potter series. Xenophilius Lovegood was interested in ideas far outside the mainstream wizarding world.4/10Palaeophile Definition:one fond of or informed about what is ancient About the Word: Both palaios- and archaios- meant "ancient" in Greek, but while paleontologists study fossils, archaeologists study human artifacts. Of course, both paleontologists and archaeologists - and any lovers of antiquity - can be palaeophiles.5/10Germanophile Definition:one who approves or favors the German people and their institutions and customs About the Word: Not surprisingly, other countries have their own admirers too: Anglophiles (England), Francophiles (France), Italophiles (Italy), Russophiles (Russia), Japanophiles (Japan), and Sinophiles (China).6/10Ailurophile Definition:cat fancier; lover of cats About the Word: Ancient Egyptians loved cats and honored them by depicting gods and goddesses in feline form (for example, the goddess Bastet); still, the prefix ailur- (meaning "cat") crept into English as a gift from the Greeks.7/10Astrophile Definition:one fond of star lore; an amateur astronomer About the Word: Astr, Latin for "star," turns up in the word disaster, which originally referred to "an unfavorable aspect of a star or planet. "8/10Phonophile Definition:collector or connoisseur of phonograph records About the Word: Record lovers have long been coining terms for their passion. Gramophile comes from the Gramophone (phonograph) trademarked in the late 19th century. Discophile dates to 1940. The similar audiophile (enthusiast of high-fidelity sound reproduction) appeared in 1951.9/10Cinephile Definition:devotee of motion pictures; cineast About the Word: Like bibliophile ("book lover"), cinephile was borrowed directly from French into English. What's the difference between a cinephile and a "movie lover"? The distinction is vague, but cinephile - with its classical tone - suggests a scholarly interest.10/10More Words At Play Mueller Questions, U. S. May Sanction 'Oligarchs''government in which a small group exercises control''Precedent' vs. 'Precedence'Don't set a precedence.2017 Word of the Year: Behind the Scenes How we chose 'feminism'A Whole Barnyard of Farm Idioms24 down-home turns of phrase Commentsshow TRENDING NOWoligarch'government in which a small group exercises control'glib'insincere to the point of being deceitful'depose'to take testimony from especially by deposition'omnibus'containing or including many items'acrimony'anger and bitterness'SEE ALLLearn a new word every day. Delivered to your inbox!Love words? Need even more definitions? Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!Merriam-Webster unabridged  Laccolith From Wikipedia, the free encyclopedianavigation search For hydrolaccolith, a mound of earth-covered ice formed by frost heaving in the Arctic and subarctic environments, see Pingo. A laccolith is a sheet intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the laccolith a dome or mushroom-like form with a generally planar base. A laccolith intruding into and deforming strata Laccolith exposed by erosion of overlying strata in Montana Pink monzonite laccolith intrudes within the grey Cambrian and Ordovician strata near Notch Peak, Utah Laccoliths tend to form at relatively shallow depths and are typically formed by relatively viscous magmas, such as those that crystallize to diorite, granodiorite, and granite. Cooling underground takes place slowly, giving time for larger crystals to form in the cooling magma. The surface rock above laccoliths often erodes away completely, leaving the core mound of igneous rock. The term was first applied as laccolite by Grove Karl Gilbert after his study of intrusions of diorite in the Henry Mountains of Utah in about 1875. The filled and solidified magma chamber of Torres del Paine (Patagonia) is one of the best exposed laccoliths, built up incrementally by horizontal granitic and mafic magma intrusions over 162 ± 11 thousand years. [1] Horizontal sheeted intrusions were fed by vertical intrusions. [2]It is often difficult to reconstruct shapes of intrusions. For instance, Devils Tower in Wyoming was thought to be a volcanic neck, but study has suggested it may be an eroded laccolith. [3] The rock would have had to cool very slowly so as to form the slender pencil-shaped columns of phonolite porphyry seen today. However, erosion has stripped away the overlying and surrounding rock, and so it is impossible to reconstruct the original shape of the igneous intrusion; that rock may not be the remnant of a laccolith. At other localities, such as in the Henry Mountains and other isolated mountain ranges of the Colorado Plateau, some intrusions demonstrably have shapes of laccoliths. The small Barber Hill syenite -stock laccolith in Charlotte, Vermont, has several volcanic trachyte dikes associated with it. Molybdenite is also visible in outcrops on this exposed laccolith. In Big Bend Ranch State Park, at the southwesternmost visible extent of the Ouachita orogeny, lies the Solitario. [4] It consists of the eroded remains of a laccolith, presumably named for the sense of solitude that observers within the structure might have, due to the partial illusion of endless expanse in all directions. [4]One of the largest laccoliths in the United States is Pine Valley Mountain in the Pine Valley Mountain Wilderness area near St. George, Utah. There are many examples of possible laccoliths on the surface of the Moon. [5] These igneous features may be confused with impact cratering. See also [ edit]Batholith Dike Hydrolaccolith Lopolith Sill Stock References [ edit]^ Julien Leuthold, Othmar Müntener, Lukas Baumgartner, Benita Putlitz, Maria Ovtcharova and Urs Schaltegger, Time resolved construction of a bimodal laccolith (Torres del Paine, Patagonia), Earth and Planetary Science Letters, 325-326:85-92, 2012^ Julien Leuthold, Othmar Müntener, Lukas Baumgartner, Benita Putlitz, Petrological constraints on the recycling of mafic crystal mushes and intrusion of braided sills in the Torres del Paine Mafic Complex (Patagonia), Journal of Petrology, 55 (5):917-949, 2014^ Vitaliano, Dorothy B. "Geomythology: geological origins of myths and legends" in Myth and Geology, ed. L. Piccardi and W. B. Masse, p. 1. Geological Society of London. ISBN 978-1-86239-216-8^ a b Spearing, Darwin. Roadside Geology of Texas. 1991. Mountain Press Publishing Company. ISBN 978-0-87842-265-4.^ Wichman, R. W. and Schultz, P. H. (1996) Crater-Centered Laccoliths on the Moon: Modeling Intrusion Depth and Magmatic Pressure at the Crater Taruntius, Icarus, Volume 122, Issue 1, July 1996, pages 193-199. doi: 10.1006/icar.1996.0118Blatt, Harvey and Robert J. Tracy, 1996, Petrology: Igneous, Sedimentary and Metamorphic, 2nd ed., pp. 13–15, Freeman, ISBN 0-7167-2438-3Jules D. Friedman and Curtis Huffman, Jr., coordinators, " Laccolith Complexes of Southeastern Utah: Time of Emplacement and Tectonic Setting -- Workshop Proceedings ", United States Geological Survey Bulletin 2158, 1998. External links [ edit]The dictionary definition of laccolith at Wiktionary Categories: Petrology Igneous rocks Sheet intrusions Geologic domes Laccoliths  . EENS 1110Physical Geology Tulane University Prof. Stephen A. Nelson Metamorphism and Metamorphic Rocks This page last updated on 25-Sep-2017Definition of Metamorphism The word " Metamorphism " comes from the Greek: meta = after, morph = form, so metamorphism means the after form. In geology this refers to the changes in mineral assemblage and texture that result from subjecting a rock to pressures and temperatures different from those under which the rock originally formed. The original rock that has undergone metamorphism is called the protolith. Protolith can be any type of rock and sometimes the changes in texture and mineralogy are so dramatic that is difficult to distinguish what the protolith was. Note that diagenesis and weathering are also a changes in form that occur in rocks. In geology, however, we restrict diagenetic processes to those which occur at temperatures below 200 o C and pressures below about 300 MPa (MPa stands for Mega Pascals), this is equivalent to about 3,000 atmospheres of pressure. Metamorphism therefore occurs at temperatures and pressures higher than 200 o C and 300 MPa. Rocks can be subjected to these higher temperatures and pressures as they become buried deeper in the Earth. Such burial usually takes place as a result of tectonic processes such as continental collisions or subduction. The upper limit of metamorphism occurs at the pressure and temperature of wet partial melting of the rock in question. Once melting begins, the process changes to an igneous process rather than a metamorphic process. During metamorphism the protolith undergoes changes in texture of the rock and the mineral make up of the rock. These changes take place mostly in the solid state and are caused by changes in physical or chemical conditions, which in turn can be caused by such things as burial, tectonic stress, heating by magma or interactions with fluids. Factors that Control Metamorphism Metamorphism occurs because rocks undergo changes in temperature and pressure and may be subjected to differential stress and hydrothermal fluids. Metamorphism occurs because some minerals are stable only under certain conditions of pressure and temperature. When pressure and temperature change, chemical reactions occur to cause the minerals in the rock to change to an assemblage that is stable at the new pressure and temperature conditions. But, the process is complicated by such things as how the pressure is applied, the time over which the rock is subjected to the higher pressure and temperature, and whether or not there is a fluid phase present during metamorphism. Temperature Temperature increases with depth in the Earth along the Geothermal Gradient. Thus higher temperature can occur by burial of rock. Temperature can also increase due to igneous intrusion. Pressure increases with depth of burial, thus, both pressure and temperature will vary with depth in the Earth. Pressure is defined as a force acting equally from all directions. It is a type of stress, called hydrostatic stress , or uniform stress. If the stress is not equal from all directions, then the stress is called a differential stress. There are two kinds of differential stress. Normal stress causes objects to be compressed in the direction of maximum principal stress and extended in the direction of minimal stress. If differential stress is present during metamorphism, it can have a profound effect on the texture of the rock. Shear stress causes objects to be smeared out in the direction of applied stress. Differential stress if acting on a rocks can have a profound affect on the appearance or texture of the rock. Rounded grains can become flattened in the direction of maximum stress. Minerals that crystallize or grow in the differential stress field can have a preferred orientation. This is especially true of the sheet silicate minerals (the micas: biotite and muscovite, chlorite, talc, and serpentine). These sheet silicates will grow with their sheets orientated perpendicular to the direction of maximum stress. Preferred orientation of sheet silicates causes rocks to be easily broken along approximately parallel sheets. Such a structure is called a foliation. Fluid Phase.- Any existing open space between mineral grains in a rock can potentially contain a fluid. This fluid is mostly H 2 O, but contains dissolved ions. The fluid phase is important because chemical reactions that involve changing a solid mineral into a new solid mineral can be greatly speeded up by having dissolved ions transported by the fluid. If chemical alteration of the rock takes place as a result of these fluids, the process is called metasomatism . Time - Because metamorphism involves changing the rock while it is solid, metamorphic change is a slow process. During metamorphism, several processes are at work. Recrystallization causes changes in minerals size and shape. Chemical reactions occur between the minerals to form new sets of minerals that are more stable at the pressure and temperature of the environment, and new minerals form as a result of polymorphic phase transformations (recall that polymorphs are compounds with the same chemical formula, but different crystal structures. Laboratory experiments suggest that the the sizes of the mineral grains produced during metamorphism increases with time. Thus coarse grained metamorphic rocks involve long times of metamorphism. Experiments suggest that the time involved is tens of millions of years. Grade of Metamorphism Metamorphic grade is a general term for describing the relative temperature and pressure conditions under which metamorphic rocks form. As the temperature and/or pressure increases on a body of rock we say that the rock undergoes prograde metamorphism or that the grade of metamorphism increases. Low-grade metamorphism takes place at temperatures between about 200 to 320 o C, and relatively low pressure. Low grade metamorphic rocks are characterized by an abundance of hydrous minerals (minerals that contain water, H 2 O, in their crystal structure). Examples of hydrous minerals that occur in low grade metamorphic rocks: Clay Minerals Serpentine Chlorite High-grade metamorphism takes place at temperatures greater than 320 o C and relatively high pressure. As grade of metamorphism increases, hydrous minerals become less hydrous, by losing H 2 O and non-hydrous minerals become more common. Examples of less hydrous minerals and non-hydrous minerals that characterize high grade metamorphic rocks: Muscovite - hydrous mineral that eventually disappears at the highest grade of metamorphism Biotite - a hydrous mineral that is stable to very high grades of metamorphism. Pyroxene - a non hydrous mineral. Garnet - a non hydrous mineral. Retrograde Metamorphism As temperature and pressure fall due to erosion of overlying rock or due to tectonic uplift, one might expect metamorphism to a follow a reverse path and eventually return the rocks to their original unmetamorphosed state. Such a process is referred to as retrograde metamorphism . If retrograde metamorphism were common, we would not commonly see metamorphic rocks at the surface of the Earth. Since we do see metamorphic rocks exposed at the Earth's surface retrograde metamorphism does not appear to be common. The reasons for this include:chemical reactions take place more slowly as temperature is decreasedduring prograde metamorphism, fluids such as H 2 O and CO 2 are driven off, and these fluids are necessary to form the hydrous minerals that are stable at the Earth's surface.chemical reactions take place more rapidly in the presence of fluids, but if the fluids are driven off during prograde metamorphism, they will not be available to speed up reactions during retrograde metamorphism. Metamorphic Rock Types There are two major subdivisions of metamorphic rocks. Foliated – These have a planar foliation caused by the preferred orientation (alignment) of minerals and formed under differential stress. They have a significant amount of sheet silicate (platy minerals and are classified by composition, grain size, and foliation type. Non-foliated – These have no evident planar fabric or foliation, crystallized under conditions where there was no differential stress, and are comprised of equant minerals only. These are classified mainly by the minerals present or the chemical composition of the protolith. Foliated Metamorphic Rocks Example - metamorphism of a shale, made up initially of clay minerals and quartz all of clay or silt size. Slate - Slates form at low metamorphic grade by the growth of fine grained chlorite and clay minerals. The preferred orientation of these sheet silicates causes the rock to easily break along the planes parallel to the sheet silicates, causing a slatey cleavage. Note that in the case shown here, the maximum stress is applied at an angle to the original bedding planes, so that the slatey cleavage has developed at an angle to the original bedding. Because of the nearly perfect breakage along planes, slates are useful for blackboards and shingles. Phyllite - Fine mica-rich rock, formed by low – medium grade metamorphism. In a phyllite, the clay minerals have recrystallized into tiny micas (biotite and muscovite which reflect a satiny luster. Phyllite is between slate and schist. Schist - The size of the mineral grains tends to enlarge with increasing grade of metamorphism. Eventually the rock develops a near planar foliation caused by the preferred orientation of sheet silicates (mainly biotite and muscovite). Quartz and Feldspar grains, however show no preferred orientation. The irregular planar foliation at this stage is called schistosity. Schist often has other minerals besides micas. These include minerals like - Quartz, Feldspars, Kyanite, Garnet, Staurolite, and Sillimanite. When these non-mica minerals occur with a grain size greater than the rest of the rock, they are called pophyroblasts . Gneiss As metamorphic grade increases, the sheet silicates become unstable and dark colored minerals like hornblende and pyroxene start to grow. These dark colored minerals tend to become segregated in distinct bands through the rock, giving the rock a gneissic banding . Because the dark colored minerals tend to form elongated crystals, rather than sheet- like crystals, they still have a preferred orientation with their long directions perpendicular to the maximum differential stress. Granulite - At the highest grades of metamorphism all of the hydrous minerals and sheet silicates become unstable and thus there are few minerals present that would show a preferred orientation. The resulting rock will have a granulitic texture that is similar to a phaneritic texture in igneous rocks. Migmatites – If the temperature reaches the solidus temperature (first melting temperature), the rock may begin to melt and start to co-mingle with the solids. Usually these melts are felsic with the mafic material remaining metamorphic. Non-foliated Metamorphic Rocks Non-foliated rocks lack a planar fabric . Absence of foliation possible for several reasons: Rock not subjected to differential stress. Dominance of equant minerals (like quartz, feldspar, and garnet). Absence of platy minerals (sheet silicates). Non-foliated rocks are given specific names based on their mineralogy and composition: Amphibolite - These rocks are dark colored rocks with amphibole (usually hornblende) as their major mineral. They are usually poorly foliated and form at intermediate to high grades of metamorphism of basaltic or gabbroic protoliths. Hornfels - These are very fine grained rocks that usually form as a result of magma intruding into fined grained igneous rocks or shales. The magma causes a type of metamorphism called contact metamorphism (to be discussed later). Quartzite - A rock made up almost entirely of quartz. They are formed by metamorphism of quartz arenites (sandstones). Since quartz is stable over a large range of temperatures and pressures, no new minerals are formed during metamorphism, and the only metamorphic effect that occurs is recrystallization of the quartz resulting in interlocking crystals that make up a very hard rock. Marble - A limestone or dolostone made up only of calcite or dolomite will metamorphose to a marble which is made mostly recrystallized calcite or dolomite. The Recrystallization usually obliterates all fossils. Marbles have a variety of colors and are often complexly banded. They are commonly used as a decorative stone. Protolith Composition Although textures and structures of the protolith are usually destroyed by metamorphism, we can still get an idea about the original rock from the minerals present in the metamorphic rock. Minerals that form, do so because the chemical elements necessary to form them are present in the protolith. General terms used to describe the chemical composition of both the protolith and the resulting metamorphic rock are: Pelitic Alumina rich rocks, usually shales or mudstones. These start out originally with clay minerals and as a result of metamorphism, Alumina rich minerals like micas, chlorite, garnet, kyanite, sillimanite and andalusite form. Because of the abundance of sheet silicates, pelitic rocks commonly form slates, phyllites, schists, and gneisses during metamorphism. Mafic - These are Mg and Fe rich rocks with low amounts of Si. Minerals like biotite, hornblende and plagioclase form during metamorphism and commonly produce amphibolites. Calcareous - These are calcium-rich rocks usually derived from limestones or dolostones, and thus contain an abundance of Calcite. Marbles are the type of metamorphic rock that results. Quartzo-Feldspathic - Rocks that contain an abundance of quartz and feldspar fall into this category. Protoliths are usually granites, rhyolites, or arkose sandstones and metamorphism results in gneisses containing an abundance of quartz, feldspar, and biotite. Types of Metamorphism Metamorphism can take place in several different environments where special conditions exist in terms of pressure, temperature, stress, conditions, or chemical environments. We here describe several diff rent types of metamorphism that are recognized. Contact Metamorphism (also called thermal metamorphism) - Occurs adjacent to igneous intrusions and results from high temperatures associated with the igneous intrusion. Since only a small area surrounding the intrusion is heated by the magma, metamorphism is restricted to a zone surrounding the intrusion, called a metamorphic aureole . Outside of the contact aureole, the rocks are unmetamorphosed. The grade of metamorphism increases in all directions toward the intrusion. Because temperature differences between the surrounding rock and the intruded magma are larger at shallow levels in the crust, contact metamorphism is usually referred to as high temperature, low pressure metamorphism. The rock produced is often a fine-grained rock that shows no foliation, called a hornfels. Burial Metamorphism - When sedimentary rocks are buried to depths of several hundred meters, temperatures greater than 300 o C may develop in the absence of differential stress. New minerals grow, but the rock does not appear to be metamorphosed. The main minerals produced are the Zeolites. Burial metamorphism overlaps, to some extent, with diagenesis, and grades into regional metamorphism as temperature and pressure increase. Dynamic Metamorphism - This type of metamorphism is due to mechanical deformation, like when two bodies of rock slide past one another along a fault zone. Heat is generated by the friction of sliding along the zone, and the rocks tend to crushed and pulverized due to the sliding. Dynamic metamorphism is not very common and is restricted to a narrow zone along which the sliding occurred. The rock that is produced is called a mylonite. Regional Metamorphism - This type of metamorphism occurs over large areas that were subjected to high degrees of deformation under differential stress. Thus, it usually results in forming metamorphic rocks that are strongly foliated, such as slates, schists, and gneisses. The differential stress usually results from tectonic forces that produce a compression of the rocks, such as when two continental masses collide with one another. Thus, regionally metamorphosed rocks occur in the cores of mountain ranges or in eroded mountain ranges. Compressive stresses result in folding of the rock, as shown here, and results in thickening of the crust which tends to push rocks down to deeper levels where they are subjected to higher temperatures and pressures (See Figure 8.20 in your text). A map of a hypothetical regionally metamorphosed area is shown in the figure below. Most regionally metamorphosed areas can be divided into zones where a particular mineral, called an index mineral, is characteristic of the zone. The zones are separated by lines (surfaces in three dimensions) that mark the first appearance of the index mineral. These lines are called isograds (meaning equal grade) and represent lines (really surfaces) where the grade of metamorphism is equal. A map of a regionally metamorphosed areas are can be seen in figure 8.16 of your text. Hydrothermal Metamorphism - Near oceanic ridges where the oceanic crust is broken up by extensional faults, sea water can descend along the cracks. Since oceanic ridges are areas where new oceanic crust is created by intrusion and eruption of basaltic magmas, these water-rich fluids are heated by the hot crust or magma and become hydrothermal fluids. The hydrothermal fluids alter the basaltic oceanic crust by producing hydrous minerals like chlorite and talc. Because chlorite is a green colored mineral the rocks hydrothermal metamorphic rocks are also green and often called greenstones. Subduction Related Metamorphism - At a subduction zone, the oceanic crust is pushed downward resulting in the basaltic crust and ocean floor sediment being subjected to relatively high pressure. But, because the oceanic crust by the time it subducts is relatively cool, the temperatures in the crust are relatively low. Under the conditions of low temperature and high pressure, metamorphism produces an unusual blue mineral, glaucophane. Compressional stresses acting in the subduction zone create the differential stress necessary to form schists and thus the resulting metamorphic rocks are called blueschist Shock Metamorphism - When a large meteorite collides with the Earth, the kinetic energy is converted to heat and a high pressure shock wave that propagates into the rock at the impact site. The heat may be enough to raise the temperature to the melting temperature of the earth rock. The shock wave produces high enough pressure to cause quartz to change its crystal structure to more a dense polymorph like coesite or stishovite. Ancient meteorite impact sites have been discovered on the basis of finding this evidence of shock metamorphism. Metamorphic Facies In general, metamorphic rocks do not undergo significant changes in chemical composition during metamorphism. The changes in mineral assemblages are due to changes in the temperature and pressure conditions of metamorphism. Thus, the mineral assemblages that are observed must be an indication of the temperature and pressure environment that the rock was subjected to. This pressure and temperature environment is referred to as Metamorphic Facies. The sequence of metamorphic facies observed in any metamorphic terrain, depends on the geothermal gradient that was present during metamorphism. A high geothermal gradient such as the one labeled "A" in the figure shown here, might be present around an igneous intrusion, and would result in metamorphic rocks belonging to the hornfels facies. Under a normal geothermal gradient, such as "B" in the figure, rocks would progress from zeolite facies to greenschist, amphibolite, and eclogite facies as the grade of metamorphism (or depth of burial) increased. If a low geothermal gradient was present, such the one labeled "C" in the diagram, then rocks would progress from zeolite facies to blueschist facies to eclogite facies. Thus, if we know the facies of metamorphic rocks in the region, we can determine what the geothermal gradient must have been like at the time the metamorphism occurred. The Rock Cycle Before moving on to the rest of the course, you should read Interlude C in your textbook (pages 261-268). Now that we have discussed the three types of rocks, it is important to understand how the atoms that make up these rocks cycle through the earth. This cycling involves process that will be discussed in detail throughout the remainder of this course. Since the rock cycle links the rock forming processes to tectonic process and to surface process (most of which will be discussed throughout the rest of the course) , it is important to understand the concept of the rock cycle and the various linkages involved. The rock cycle involves cycling of elements between various types of rocks, and thus mostly involves the lithosphere. The rock cycle involves the three types of rocks as reservoirs (1) igneous, (2) sedimentary, and (3) metamorphic. Chemical elements can reside in each type of rock, and geologic processes move these elements into another type of rock. Energy for the parts of the crustal cycle near the Earth's surface is solar and gravitational energy (which control erosion and weathering), whereasenergy that drives processes beneath the surface is geothermal and gravitational energy (which control uplift, subsidence, melting, and metamorphism). We here start our discussion with Volcanoes and Volcanic eruptions and processes that are involved in the production of igneous rocks at the earth's surface. Questions on this material that might be asked on an exam Define the following: (a) geothermal gradient, (b) metamorphism, (c) differential stress, (d) prograde metamorphism, (e) metasomatism (f) protolith, (g) foliation, (i) metamorphic aureole, (j) isograd, (k) greenstone, (l) blueschist. Starting with a shale, describe the textural changes that would occur to the rock during prograde metamorphism with differential stress conditions present. Why is retrograde metamorphism uncommon? Describe the following non-foliated metamorphic rocks (a) amphibolite, (b) quartzite, (c) marble, (d) hornfels. What are the terms used to describe the general chemical composition of metamorphic rocks?. Describe the type of rocks and minerals four nd in each. What are the various types of metamorphism? Describe the rocks produced by each. What is the progression of metamorphic facies that would occur along a high geothermal gradient, a normal geothermal gradient, and a low geothermal gradient. Return to EENS 1110 Page  Geological Terms Beginning With "L" Home » Geology Dictionary Geological Terms Beginning With "L"For terms beginning with other letters, please click below A B C D E F G H I J K L M N O P Q R S T U V W X Y ZLabradorescence A display of spectral colors caused when light enters a material, strikes twinning or other planar surfaces within the stone and then reflects from them. Different twinning surfaces within the stone can reflect different colors of light to produce the visual effect of a stone with different color domains. This phenomenon is best known in the mineral labradorite, for which it is named. Highly labradorescent specimens of labradorite are given the trade name of "spectrolite" for their bold spectral colors. Labradorite A gemstone variety of plagioclase feldspar that produces flashes of iridescent blue, green, yellow, orange, or red when moved under incident light. This luster is known as labradorescence. Laccolith An igneous intrusion that has been forced between two layered sedimentary rock units. The pressure of the injecting magma was high enough to deform the overlying strata. The roof of the intrusion is convex upwards and the floor of the intrusion is nearly flat. Lacustrine The word "lacustrine" means "of a lake." In geology the word is used for the depositional environment or a habitat that is found in lakes. Lacustrine environments are usually, but not always, fresh water. They are also usually, but not always low energy. The USGS image shows scientists sampling glacial lake clays associated with landslide problems at Tulley Valley, New York. Lahar A mudflow composed of water and volcanic ash. Lahars can be triggered by the flash melting of the snow cap of a volcanic mountain or by heavy rain. Lahars are very dangerous because they can occur suddenly and travel at great speeds. They can travel faster than the streams in the valleys that they pass through, sweeping up stream water, sediment and other debris, and growing in mass as they flow. The photo shows a lahar exiting the crater of Mount St. Helens in 1982. The lahar flowed down the mountain, entered the North Fork Toutle River valley and eventually entered the Cowlitz River about 50 miles downstream. Laminar Flow A state of uniform flow within a fluid in which the moving particles travel along parallel paths (compare with Turbulent Flow). Landslide The movement of rock, soil, volcanic ash or other material, downslope under the influence of gravity. There are many types of landslides that include: slumps, creep, earthflows, debris flows, debris avalanches, topples, rock falls, mudflows, and debris slides are examples. Landslides are often triggered by rain fall, snow melt, overloading or earthquakes. Dictionary of Geological Terms - Only $18.95 All scientific disciplines have an essential vocabulary that students and professionals must understand to learn and communicate effectively. A geology dictionary that is used regularly is one of the most important tools for developing professional competence. A good dictionary should be on the desk of every geologist and within easy reach. This dictionary is compact and inexpensive at only $18.95. More information. Lapilli Volcanic rock materials which are formed when magma is ejected by a volcano. Typically used for tephra that ranges between 2 and 64 millimeters in diameter. Larimar Larimar is a rare blue variety of pectolite found only in the Dominican Republic. It is popular because of its delicate blue color. It must be used with care because it is fragile and will fade with long exposure to bright light. Lateral Moraine An accumulation of rock debris along the sides of a glacier in contact with the valley walls. It is mainly weathering debris that fell from the valley wall rather than material moved by and deposited by ice. Lava Molten rock that has erupted onto Earth's surface. The word is also used for the solidified flows and fragments after they have cooled. The image shows a pahoehoe flow on Kilauea Volcano, Hawaii. Not to be confused with "magma," which is the same material while it is beneath Earth's surface. Lava Channel Pathways of lava movement across the surface of a volcano. They can be straight or meandering depending upon the steepness of slope and the obstacles. The photo is a lava channel on the surface of Kilauea Volcano, Hawaii in 1990. Lava Dome A round, steep-sided extrusion of very viscous lava that is squeezed from a volcanic vent without major eruption. The lava is too viscous to flow and is composed of rhyolite or dacite. The dome shown in the photo is the vent of the Novarupta eruption of 1912, the largest volcanic eruption of the 20th century. The small dome was overlooked when the source of the eruption was originally determined and the wrong volcano was blamed. Also called "volcanic domes. "Lava Tube When the surface of a lava flow solidifies but the lava keeps flowing below, a tunnel can remain after all of the lava drains away. The photo shows an opening into a lava tube at the Lava Beds National Monument in California. Leaching The removal of soluble constituents from a rock or soil by moving groundwater or hydrothermal fluids. Lease Bonus Money paid to a mineral rights owner in exchange for granting a lease. This payment may be in addition to any rental or royalty payments. Left-Lateral Fault A fault with horizontal movement. If you are standing on one side of the fault and look across it the block on the opposite side of the fault has moved to the left. (Also see Right-Lateral Fault . )Lepidolite A lithium-rich mica with a rose to lilac color and an aventurescent luster that is sometimes used to make cabochons, tumbled stones and other lapidary projects. Levee A long continuous ridge built by people along the banks of a stream to contain the water during times of high flow. Limb One side of a fold. The dipping rock units between the crest of an anticline and the trough of a syncline. Limestone A sedimentary rock consisting of at least 50% calcium carbonate (Ca CO2) by weight. Picture of Limestone. Lineament A straight topographic feature of regional extent which is thought to represent crustal structure. A fault, line of sinkholes, straight stream stretch or a line of volcanoes can be considered linear features. Liquefied Natural Gas (LNG)Natural gas that has been converted to the liquid state by reducing its temperature. (At standard surface temperature and pressure the liquification temperature is about -260 degrees Fahrenheit. )Lithification The processes through which sediments are converted into sedimentary rock, including compaction and cementation. Lithology The study and description of rocks, including their mineral composition and texture. Also used in reference to the compositional and textural characteristics of a rock. Lithosphere The rigid outer shell of the earth which includes the crust and a portion of the upper mantle. Lithospheric Plate A large slab of the lithosphere that can be moved by convection current motion within the mantle. Load The total amount of sediment being carried by a stream or a glacier. Includes suspended materials, dissolved materials and materials moved along Earth's surface. (Also see: bed load, dissolved load, suspended load . )Lode A rich accumulation of minerals in solid rock. Frequently in the form of a vein, layer or an area with a large concentration of disseminated particles. (See placer deposit for contrast. )Longitudinal Dune A long, narrow sand dune that has its long dimension oriented parallel to the direction of the wind. It moves in the same direction as the wind. Longitudinal Profile A cross section of a stream or valley beginning at the source and continuing to the mouth. These profiles are drawn to illustrate the gradient of the stream. Longshore Current A flow of water parallel to a coastline that is caused by waves striking the coast at an oblique angle. Longshore Drift The movement of sediment along a coastline caused by waves striking the coast at an oblique angle. The waves wash sediment particles up the beach at an oblique angle and the swash back to the sea carries the particles down the gradient of the beach. This produces a zig-zag path of particle movement along the beach. Lopolith An igneous intrusion that has been forced between two layered rock units. The floor of the intrusion is convex downwards and the roof of the intrusion is nearly flat. Losing Stream Also known as an "influent stream." A stream, usually flowing in an arid area, that loses water into the ground through the bottom of its channel. This loss occurs because the water table is below the channel of the stream. Influent streams decrease in discharge in a downstream direction and often lose all of their water into the ground. Lowland A relatively flat area in the lower levels of regional elevation. Low-Velocity Zone A zone within the upper mantle where seismic wave velocities are relatively low. This zone is located about 35 to 155 miles below the surface. Luster The manner in which light reflects from the surface of a mineral. Metallic, submetallic and non-metallic are the basic types of luster. Other types of luster include: vitreous, dull, resinous, adamantine, earthy, pearly, greasy, silky, and waxy. The intensity of luster is often described in simple terms such as bright or dull. In the photo are specimens of tumble-polished hematite with a bright metallic luster. A B C D E F G H I J K L M N O P Q R S T U V W X Y ZMore General Geology What Does a Geologist Do? Land Below Sea Level Divisions of Geologic Time Minerals Waterproof Paper Plate Tectonics What Is Earth Science? Rocks More From Geology.com: Geology.com News contains news about geology and earth science from around the world. Dacite - a light-colored extrusive igneous rock intermediate between rhyolite and andesite. Gemstones - Colorful images and articles about diamonds and colored stones. Green Diamonds - one of rarest and most valuable diamond colors. Rock Gallery: Photos of igneous, sedimentary and metamorphic rocks. Minerals: Information about ore minerals, gem materials and rock-forming minerals. What is Geology? The study of Earth materials, structures, processes and life over time. US Diamond Mines - Did you know that diamonds have been mined in the United States?  . Diversity of Metabolism in Procaryotes (page 5) (This chapter has 8 pages)© Kenneth Todar, Ph DLithotrophic Types of Metabolism Lithotrophy is the use of an inorganic compound as a source of energy. Most lithotrophic bacteria are aerobic respirers that produce energy in the same manner as all aerobic respiring organisms: they remove electrons from a substrate and put them through an electron transport system that will produce ATP by electron transport phosphorylation. Lithotrophs just happen to get those electrons from an inorganic, rather than an organic compound. Some lithotrophs are facultative lithotrophs, meaning they are able to use organic compounds, as well, as sources of energy. Other lithotrophs do not use organic compounds as sources of energy; in fact, they won't transport organic compounds. CO 2 is the sole source of carbon for the methanogens and the nitrifying bacteria and a few other species scattered about in other groups. These lithoautotrophs are often referred to as "chemoautotrophs", but the term lithoautotroph is a more accurate description of their metabolism. The lithotrophs are a very diverse group of procaryotes, united only by their ability to oxidize an inorganic compound as an energy source. Lithotrophy runs through the Bacteria and the Archaea . If one considers methanogen oxidation of H 2 a form of lithotrophy, then probably most of the Archaea are lithotrophs. Lithotrophs are usually organized into "physiological groups" based on their inorganic substrate for energy production and growth (see Table 5 below). Table 5. Physiological groups of lithotrophsphysiological group energy source oxidized end product organismhydrogen bacteria H 2 H 2 O Alcaligenes, Pseudomonasmethanogens H 2 H 2 O Methanobacteriumcarboxydobacteria CO CO 2Rhodospirillum, Azotobacternitrifying bacteria* NH 3 NO 2 Nitrosomonasnitrifying bacteria* NO 2 NO 3 Nitrobactersulfur oxidizers H 2 S or S SO 4Thiobacillus, Sulfolobusiron bacteria Fe ++ Fe +++ Gallionella, Thiobacillus* The overall process ofnitrification, conversion of NH3to NO3, requires a consortium of microorganisms. The hydrogen bacteria oxidize H 2 (hydrogen gas) as an energy source. The hydrogen bacteria are facultative lithotrophs as evidenced by the pseudomonads that fortuitously possess a hydrogenase enzyme that will oxidize H 2 and put the electrons into their respiratory ETS. They will use H 2 if they find it in their environment even though they are typically heterotrophic. Indeed, most hydrogen bacteria are nutritionally-versatile in their ability to use a wide range of carbon and energy sources. Some hydrogen bacteria possess an NAD-linked hydrogenase that transfers electrons from H 2 to NAD in a one-step process. NAD then delivers the electrons to the ETS. Others have hydrogenase enzymes that pass electrons to different carriers in the bacterial electron transport system. The methanogens used to be considered a major group of hydrogen bacteria - until it was discovered that they are Archaea. The methanogens are able to oxidize H 2 as a sole source of energy while transferring the electrons from H 2 to CO 2 in its reduction to methane. Apparently, H 2 has more energy available than CH 4 , for all you physical chemists out there. Metabolism of the methanogens is absolutely unique, yet methanogens represent the most prevalent and diverse group of Archaea. Methanogens use H 2 and CO 2 to produce cell material and methane. They have unique coenzymes and electron transport processes. Their type of energy generating metabolism is never seen in the Bacteria, and their mechanism of autotrophic CO 2 fixation is very rare, except in methanogens. The carboxydobacteria are able to oxidize CO (carbon monoxide) to CO 2, using an enzyme CODH ( carbon monoxide dehydrogenase ). The carboxydobacteria are not obligate CO users, i.e., some are also hydrogen bacteria, and some are phototrophic bacteria. Interestingly, the enzyme CODH used by the carboxydobacteria to oxidize CO to CO 2, is used by the methanogens for the reverse reaction - the reduction of CO 2 to CO - during CO 2 fixation by the CODH pathway (Figure 23). The nitrifying bacteria are represented by two genera, Nitrosomonas and Nitrobacter. Together these bacteria can accomplish the oxidation of NH 3 to NO 3, known as the process of nitrification . No single organism can carry out the whole oxidative process. Nitrosomonas oxidizes ammonia to NO 2 and Nitrobacter oxidizes NO 2 to NO 3. Most of the nitrifying bacteria are obligate lithoautotrophs , the exception being a few strains of Nitrobacter that will utilize acetate. CO 2 fixation utilizes RUBP carboxylase and the Calvin Cycle. Nitrifying bacteria grow in environments rich in ammonia, where extensive protein decomposition is taking place. Nitrification in soil and aquatic habitats is an essential part of the nitrogen cycle. Lithotrophic sulfur oxidizers include both Bacteria (e.g. Thiobacillus ) and Archaea (e.g. Sulfolobus ). Sulfur oxidizers oxidize H 2 S (sulfide) or S (elemental sulfur) as a source of energy. Similarly, the purple and green sulfur bacteria oxidize H 2 S or S as an electron donor for photosynthesis, and use the electrons for CO 2 fixation (the dark reaction of photosynthesis). Obligate autotrophy, which is nearly universal among the nitrifiers, is variable among the sulfur oxidizers. Lithoautotrophic sulfur oxidizers are found in environments rich in H 2 S, such as volcanic hot springs and fumaroles, and deep-sea thermal vents. Some are found as symbionts and endosymbionts of higher organisms. Since they can generate energy from an inorganic compound and fix CO 2 as autotrophs, they may play a fundamental role in primary production in environments that lack sunlight. As a result of their lithotrophic oxidations, these organisms produce sulfuric acid (SO 4 ), and therefore tend to acidify their own environments. Some of the sulfur oxidizers are acidophiles that will grow at a p H of 1 or less. Some are hyperthermophiles that grow at temperatures of 115 degrees C. Iron bacteria oxidize Fe ++ (ferrous iron) to Fe +++ (ferric iron). At least two bacteria probably oxidize Fe ++ as a source of energy and/or electrons and are capable of lithoautotrophic growth: the stalked bacterium Gallionella, which forms flocculant rust-colored colonies attached to objects in nature, and Thiobacillus ferrooxidans, which is also a sulfur-oxidizing lithotroph. Figure 15. Lithotrophic oxidations of nitrifying bacteria and sufide oxidizing bacteria and archaea.chapter continued Previous Page|Next Page© Kenneth Todar, Ph. D. All rights reserved. - www.textbookofbacteriology.net  lithosphere lithospherenoun lith·o·sphere \ ˈli-thə-ˌsfir \Popularity: Bottom 40% of words Trending Now:oligarch glib depose omnibus acrimony ALLTime Traveler! Explore the year a word first appeared Definition of lithosphere: the solid part of a celestial body (such as the earth); specifically: the outer part of the solid earth composed of rock essentially like that exposed at the surface, consisting of the crust and outermost layer of the mantle, and usually considered to be about 60 miles (100 kilometers) in thickness—lithosphericplay \ ˌli-thə-ˈsfir-ik, -ˈsfer- \ adjective See lithosphere defined for kids Recent Examples of lithosphere from the Web The lithosphere, in other words, is the layer of the planet that makes up the tectonic plates.— robinson meyer, The Atlantic, "A Thorny Debate in Plate Tectonics May Finally Be Resolved," 21 Aug. 2017The lithosphere is above another layer of mantle called the asthenopshere, where the rock is at just the right pressure and temperature to flow over time and help move the plates.— erik klemetti, WIRED, "A volcanic cruise through the Mariana Islands: Part 1," 13 July 2010These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lithosphere.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback. Origin and Etymology of lithosphere International Scientific Vocabulary NEW! Time Traveler First Known Use: 1887See Words from the same year LITHOSPHERE Defined for Kidslithospherenoun lith·o·sphere \ ˈli-thə-ˌsfir \Definition of lithosphere for Students: the outer part of the solid earth Learn More about lithosphere Spanish Central: Translation of lithosphere Nglish: Translation of lithosphere for Spanish speakers Britannica.com: Encyclopedia article about lithosphere Seen and Heard What made you want to look up lithosphere? Please tell us where you read or heard it (including the quote, if possible).show  Amphibolite Amphibolite from Cape Cod, Massachusetts Garnet bearing amphibolite from Val di Fleres, Italy Amphibolid ( / 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. Amphibolite is a grouping of rocks composed mainly of amphibole and plagioclase feldspars, with little or no quartz. It is typically dark-colored and heavy, with a weakly foliated or schistose (flaky) structure. The small flakes of black and white in the rock often give it a salt-and-pepper appearance. Amphibolites need not be derived from metamorphosed mafic rocks. Because metamorphism creates minerals entirely based upon the chemistry of the protolith, certain 'dirty marls ' and volcanic sediments may actually metamorphose to an amphibolite assemblage. Deposits containing dolomite and siderite also readily yield amphibolites ( tremolite -schists, grunerite -schists, and others) especially where there has been a certain amount of contact metamorphism by adjacent granitic masses. Metamorphosed basalts create ortho-amphibolites and other chemically appropriate lithologies create para-amphibolites. Tremolite, while it is a metamorphic amphibole, is derived most usually from highly metamorphosed ultramafic rocks, and thus tremolite-talc schists are not generally considered as 'amphibolites'. A holocrystalline plutonic igneous rock composed primarily of hornblende amphibole is called a hornblendite, which is usually a crystal cumulate rock. Igneous rocks with >90% amphiboles, which have a feldspargroundmass, may be a lamprophyre. Contents [ hide ]1 Ortho-amphibolites vs. para-amphibolites2 Amphibolite facies2.1 Uralite2.2 Epidiorite3 Uses4 References Ortho-amphibolites vs. para-amphibolites [ edit]Metamorphic rocks composed primarily of amphibole, albite, with subordinate epidote, zoisite, chlorite, quartz, sphene, and accessory leucoxene, ilmenite and magnetite which have a protolith of an igneous rock are known as Orthoamphibolites. Para-amphibolites will generally have the same equilibrium mineral assemblage as orthoamphibolites, with more biotite, and may include more quartz, albite, and depending on the protolith, more calcite / aragonite and wollastonite. Often the easiest way to determine the true nature of an amphibolite is to inspect its field relationships; especially whether it is interfingered with other sediments, especially greywackes and other poorly sorted sediments. If the amphibolite appears to transgress apparent protolith bedding surfaces it is an ortho-amphibolite, as this suggests it was a dyke. Picking a sill and thin metamorphosed lava flows may be more troublesome. Thereafter, whole rock geochemistry will suitably identify ortho- from para-amphibolites. The word metabasalt was thus coined, largely to avoid the confusion between ortho-amphibolites and para-amphibolites. While not a true metamorphic rock name, as it infers an origin, it is a useful term. Amphibolite facies [ edit]Garnet amphibolite, sold as "Nordic Sunset Granite", reportedly from Murmansk area. Amphibolites define a particular set of temperature and pressure conditions known as the amphibolite facies. However, caution must be applied here before embarking on metamorphic mapping based on amphibolites alone. Firstly, for an (ortho)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. For instance, actinolite amphibole is a common product of retrograde metamorphism of basalts at (upper) greenschist facies conditions. 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. Actinolite schists are often the result of hydrothermal alteration or metasomatism, and thus may not, necessarily, be a good indicator of metamorphic conditions when taken in isolation. Secondly, the microstructure and crystal size of the rock must be appropriate. 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. Gneissic texture may occur nearby, if not then mylonite zones, foliations and ductile behaviour, including stretching lineations may occur. While it is not impossible to have remnant protolith mineralogy, this is rare. More common is to find phenocrysts of pyroxene, olivine, plagioclase and even magmatic amphibole such as pargasite rhombohedra, pseudomorphed by hornblende amphibole. Original magmatic textures, especially crude magmatic layering in layered intrusions, is often preserved. Amphibolite facies equilibrium mineral assemblages of various protolith rock types consist of: Basalt ortho-amphibolite; hornblende/actinolite +/- albite +/- biotite +/- quartz +/- accessories; often remnant greenschist facies assemblages including, notably, chlorite High-magnesia basalts; as ortho-amphibolite, but may contain anthophyllite, a Mg-rich amphibole Ultramafic rocks; tremolite, asbestiform amphibole, talc, pyroxene, wollastonite, prograde metamorphic olivine (rarely)Sedimentary para-amphibolite; hornblende/actinolite +/- albite +/- biotite +/- quartz +/- garnet (calcite +/- wollastonite)Pelites; quartz, orthoclase +/- albite, +/- biotite +/- actinolite +/- garnet +/- staurolite +/- sillimanite Amphibolite facies is usually a product of Barrovian Facies Sequence or advanced Abukuma Facies Sequence metamorphic trajectories. Amphibolite facies is a result of continuing burial and thermal heating after greenschist facies is exceeded. 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. In dry rocks, however, additional heat (and burial) may result in granulite facies conditions. Uralite [ edit]Uralites are particular hydrothermally altered pyroxenites; during autogenic hydrothermal circulation their primary mineralogy of pyroxene and plagioclase, etc. has altered to actinolite and saussurite ( albite + epidote ). The texture is distinctive, the pyroxene altered to fuzzy, radially arranged actinolite pseudomorphically after pyroxene, and saussuritised plagioclase. Epidiorite [ edit]The archaic term epidiorite is sometimes used to refer to a metamorphosed ortho-amphibolite with a protolith of diorite, gabbro or other mafic intrusive rock. In epidiorite the original clinopyroxene (most often augite) has been replaced by the fibrous amphibole uralite. Uses [ edit]Amphibolite was a favourite material for the production of adzes ( shoe-last-celts) in the central European early Neolithic ( Linearbandkeramic and Rössen cultures). [ citation needed]Amphibolite is a common dimension stone used in construction, paving, facing of buildings, especially because of its attractive textures, dark color, hardness and polishability and its ready availability. [ citation needed]References [ edit]Winter, John D., 2001. An introduction to Igneous and Metamorphic Petrology, 695 pages, Prentice Hall, ISBN 0-13-240342-0This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2011) ( Learn how and when to remove this template message)Wikimedia Commons has media related to Amphibolite. [ hide]v t e Metamorphic facies Zeolite Prehnite-pumpellyite Greenschist Blueschist Eclogite Amphibolite Granulite  lithogenesis  [lithâ²Å-jenâ²Ä-sis, lith-ojâ²Ä-nÄ] Back News | Share | Printlithogenesis [lith′ō-jen′ĕ-sis, lith-oj′ĕ-nē]Type: Term Definitions 1. Formation of calculi. Stedman’s Medical Dictionary © Wolters Kluwer Health. All rights reserved.  Felsic: Definition & Composition Your next lesson will play in 10 seconds Add to Timeline Autoplay 9.3K views Create an account to start this course today Try it free for 5 days!Create An Account Recommended Lessons and Courses for You Related Lessons Related Courses Bowen's Reaction Series: Crystallization Process & Magmatic Differentiation Batholith: Definition & Formation Unconformities in Geology: Definition & Types Detrital & Chemical Sedimentary Rocks: Definition & Differences Lesson Transcript Instructor: Suzanne Rebert Suzanne has taught college economics, geography, and statistics, and has master's degrees in agricultural economics and marine affairs (marine resource management). In this lesson, you will read about felsic rocks and find out what they're made of - their name gives clues to their composition. You'll also take a quiz to test your understanding. Definition of Felsic Rocks Felsic rocks are igneous rocks that are rich in feldspar and silicon. The word 'felsic' was made up from parts of those words. Because they are made of lighter elements, they tend to be more buoyant than mafic rocks, which are rocks high in magnesium and iron, like basalt. Granite is the most common felsic rock. It may seem strange to think of a solid granite mountain as light weight, but compared to a basalt rock of the same size, it is. Composition of Felsic Rocks Feldspar, one of the key components of felsic rock, which is the name for a group of aluminum silicate minerals containing the light metallic elements potassium, sodium, or calcium. The word 'feldspar' comes from German words meaning 'field rock.' This may not sound very specific, and in fact there are many different kinds of feldspar. As a group, feldspars form about 60% of Earth's crust. Quartz is a silicate mineral that comes in a vast array of different forms, from semiprecious gemstones to common sand. After feldspar, it's the second most important crust mineral. Granite is a felsic rock containing feldspar and quartz along with mica and amphibole, which are also silicate minerals. Because there are so many forms that all these minerals can take, there are also many types of granite. The name 'granite' refers to the grainy quality of the rock. Granite is an intrusive, or plutonic, igneous rock, which means that it's formed when magma cools and hardens in spaces within the Earth's crust. Because the magma is not exposed to the open air or water, it cools slowly and has time to form the kinds of crystals seen in a typical piece of granite. Extrusive Rhyolite is a felsic rock that, like granite, is rich in silicate minerals. However, rhyolite is extrusive. It erupts from volcanoes and cools too quickly to form large crystals. Obsidian is natural volcanic glass. Like more familiar kinds of glass, it's high in silica. The explosive volcanic eruptions that produce rhyolite are also sources of obsidian. Obsidian fractures into very sharp-edged pieces, and cultures around the world have taken advantage of this fact to make beautiful cutting tools and weapons. To unlock this lesson you must be a Study.com Member. Create your account Register for a free trial Are you a student or a teacher? I am a student I am a teacher  . EENS 2110Mineralogy Tulane University Prof. Stephen A. Nelson Phyllosilicates (Micas, Chlorite, Talc, & Serpentine)This document last updated on 18-Aug-2015Phyllosilicates (Sheet Silicates)The phyllosilicates, or sheet silicates, are an important group of minerals that includes the micas, chlorite, serpentine, talc, and the clay minerals. Because of the special importance of the clay minerals as one of the primary products of chemical weathering and one of the more abundant constituents of sedimentary rocks, they will be discussed in more detail in the next lecture. The basic structure of the phyllosilicates is based on interconnected six member rings of Si O 4-4 tetrahedra that extend outward in infinite sheets. Three out of the 4 oxygens from each tetrahedra are shared with other tetrahedra. This leads to a basic structural unit of Si 2 O 5-2. Most phyllosilicates contain hydroxyl ion, OH -, with the OH located at the center of the 6 membered rings, as shown here. Thus, the group becomes Si 2 O 5 (OH) -3 . When other cations are bonded to the Si O 4 sheets, they share the apical oxygens and the (OH) ions which bond to the other cations in octahedral coordination. This forms a layer of cations, usually Fe +2 , Mg +2, or Al +3, that occur in octahedral coordination with the O and OH ions of the tetrahedral layer. As shown, here, the triangles become the faces of the octahedral groups that can bind to the tetrahedral layers. The octahedral layers take on the structure of either Brucite [Mg (OH) 3 ], if the cations are +2 ions like Mg +2 or Fe +2, or Gibbsite [Al (OH) 3 ], if the cations are +3 like Al +3 . In the brucite structure, all octahedral sites are occupied and all anions are OH -1 . In the Gibbsite structure every 3 rd cation site is unoccupied and all anions are OH -1 . This gives rise to 2 groups of sheet silicates: The trioctahedral sheet silicates where each O or OH ion is surrounded by 3 divalent cations, like Mg +2 or Fe +2. The dioctahedral sheet silicates where each O or OH ion is surrounded by 2 trivalent cations, usually Al +3. We can build the structures of the various sheet silicates by starting with the octahedral layers similar to the structures of brucite or gibbsite, as shown below. The trioctahedral phyllosilicates are based on the structure where the octahedral layers are similar to brucite, where Mg +2 occupies the cation position. The dioctahedral phyllosilicates are based on the structure where the octahedral layers are similar to gibbsite, where Al +3 occupies the cation position. The octahedral sheets in both cases are held together by weak Van der Waals bonds. If we start with the brucite and gibbsite structures shown above, and replace 2 of the OH ions with O, where the Oxygens are now the apical Oxygens of the tetrahedral sheets, then we get the structure of the serpentine mineral, Lizardite, if the octahedral layer is trioctahedral, containing Mg +2 . If the octahedral layer is dioctahedral, containing Al +3 , the structure of the clay mineral Kaolinite, is obtained. This leads to a tetrahedral - octahedral (T-O) structure, where each T-O layer is bonded to the top (or bottom) of another T-O layer by Van der Waals bonds. If 2 more of the OH ions in the octahedral layer are replaced by O, and these O become the apical Oxygens for another tetrahedral layer, the this builds the trioctahedral phyllosilicate talc or the dioctahedral pyrophyllite. This becomes a T-O-T layer that can bond to other T-O-T layers by weak Van der Waals bonds. If an Al +3 is substituted for every 4 th Si +4 in the tetrahedral layer, this causes an excess -1 charge in each T-O-T layer. To satisfy the charge, K +1 or Na +1 can be bonded between 2 T-O-T sheets in 12-fold coordination. For the trioctahedral sheet silicates this becomes Phlogopite (Mg-biotite), and for the dioctahedral sheet silicates this becomes Muscovite. This makes a T-O-T - T-O-T layer that, again can bind to another T-O-T - T-O-T layer by weak Van der Waals bonds. It is along these layers of weak bonding that the prominent {001} cleavage in the sheet silicates occurs. Replacing 2 more Si +4 ions with Al +3 ions in the tetrahedral layer results in an excess -2 charge on a T-O-T layer, which is satisfied by replacing the K +1 with Ca +2 . This results in the trioctahedral sheet silicate - Clintonite and the dioctahedral sheet silicate - Margarite. Because of the differences in charge balance between the trioctahedral and dioctahedral sheet silicates, there is little solid solution between the two groups. However, within the trioctahedral sheet silicates there is complete substitution of Fe +2 for Mg +2 and limited substitution of Mn +2 into the octahedral sites. Within the dioctahedral sheet silicates there is limited substitution of Fe +3 for Al +3 in octahedral sites. In addition, F - or Cl - can substitute for (OH) - in the hydroxyl site. As previously discussed, substitution of F -1 stabilizes the mineral to higher pressures and temperatures. Another group of phyllosilicates that is more of mixture of structural types is the chlorite group. Although chlorite is complex in that the amount of Al that can substitute Mg and Si is variable, one way of looking at the chlorite structure is shown below. Here, the chlorite structure is depicted as consisting of a brucite-like layer (with some Al) sandwiched between tetrahedral layers that are similar to phlogopite. Another important sheet silicate structure is that of vermiculite. This is similar to the talc structure, discussed above, with layers of water molecules occurring between each T-O-T layer. Similarly, insertion of layers of water molecules between the T-O-T sheets of pyrophyllite produces the structure of smectite clays. The vermiculite and smectite groups are therefore expanding type sheet silicates and as the water is incorporated into the structure the mineral increases its volume. Although we have shown that the octahedral layers fit perfectly between the tetrahedral layers, this is an oversimplification. If the tetrahedral layers were stacked perfectly so that apical oxygens were to occur vertically aligned, then the structure would have hexagonal symmetry. But, because this is not the case, most of the phyllosilicates are monoclinic. Serpentine Group The serpentine group of minerals has the formula - Mg 3 Si 2 O 5 (OH) 4 . Three varieties of serpentine are known. Antigorite and Lizardite are usually massive and fine grained, while Chrisotile is fibrous. As discussed above, the imperfect fit of the octahedral layers and the tetrahedral layers causes the crystal structure to have to bend. In Antigorite the bending of the sheets is not continuous, but occurs in sets, similar to corrugations, as shown here. In Chrisotile, the bending of the sheets is more continuous, resulting in continuous tubes that give the mineral it's fibrous habit. The Chrisotile variety is commonly referred to as asbestos. Occurrence - Serpentine is found as an alteration product of Mg-rich silicates like pyroxene and olivine. It results due to hydration. For example:2Mg 2 Si O 4 + 3H 2 O <=> Mg 3 Si 2 O 5 (OH) 4 + Mg (OH) 2 Olivine water Serpentine Brucite Thus, serpentine is commonly found pseudomorphed after olivines and pyroxenes in altered basic and ultrabasic igneous rocks, like altered peridotites, dunites, and sometimes basalts and gabbros. It is commonly associated with minerals like magnesite (Mg CO 3 ), chromite, and magnetite. If the rock is made up almost entirely of serpentine, it is called a serpentinite. Properties - Because the serpentines usually occur either as fine-grained aggregates or fibrous crystals, optical properties are difficult to determine. Most of the time, serpentine can be distinguished by its characteristic pseudomorphing of other crystals like olivines and pyroxenes. In hand specimen it generally tends to have a dark green color with a greasy luster. In thin section it is clear to pale green to pale yellow, but does not show pleochroism, shows a generally low relief compared to minerals like olivine and pyroxene with which it is associated, and show very low order interference colors due to its low birefringence. Talc Talc has the chemical formula - Mg 3 Si 4 O 10 (OH) 2 . It is probably best know for its low hardness. Although it has a micaceous structure, it is so easily deformed, that crystals are rarely seen. Occurrence - Like serpentine, talc requires an environment rich in Mg. It is therefore found in low grade metamorphic rocks that originated as ultrabasic to basic igneous rocks. Rocks composed almost entirely of talc have a greasy feel and are referred to as soapstone. Properties - Talc is most easily distinguished in hand specimen by its low hardness, greasy feel, and association with other Mg-bearing minerals. When crystals are present they show the characteristic micaceous cleavage on {001}. In thin section, talc is colorless, biaxial negative with a 2V of 0 to 30 o . Like other sheet silicates, it shows the well developed {001} cleavage. Maximum interference colors, consistent with a birefringence of 0.05 is 3 o yellow. Muscovite has a higher birefringence and higher 2V, properties which easily distinguish the 2 minerals. Mica Group The micas can be divided into the dioctahedral micas and the trioctahedral micas, as discussed above. Muscovite, Paragonite, and Margarite are the white micas, and represent the dioctahedral group, and Biotite and Clintonite (Xanthophyllite) the black or brown mica, represents the trioctahedral group. Muscovite and Biotite are the most common micas, but the Lithium- rich, pink mica, Lepidolite, K (Li,Al) 2 Al Si 3 O 10 (OH) 2 is also common, being found mostly in pegmatites. Muscovite Muscovite, KAl 3 Si 3 O 10 (OH) 2 , and Paragonite, Na Al 3 Si 3 O 10 (OH) 2 , are two potential end members of the solid solution series involving K and Na. But, there is a large miscibility gap between the two end members with Muscovite being between 65% and 100% of K-rich end member, and Paragonite showing compositions between about 80% and 100% of the Na-rich end member. Occurrence - Muscovite is common constituent of Al-rich medium grade metamorphic rocks where is found in Al-rich schists and contributes to the schistose foliation found in these rocks. Muscovite is also found in siliceous, Al-rich plutonic igneous rocks (muscovite granites), but has not been found as a constituent of volcanic rocks. In these rocks it is commonly found in association with alkali feldspar, quartz, and sometimes biotite, garnet, andalusite, sillimanite, or kyanite. Properties - Muscovite is easily identified in hand specimen by its white to sometimes light brownish color and its perfect {001} cleavage. In thin section, the {001} cleavage is easily seen and it's high birefringence is exhibited by the large change in relief on rotation of the stage and it's 2nd to 4th order interference colors. It is clear and shows no pleochroism (which distinguishes it from Biotite), and it is biaxial negative with a 2V between 28 and 50 o . One of the most diagnostic properties of the micas, including muscovite, is the mottled or birds-eye extinction exhibited by these minerals. Biotite Biotite is a solid solution between the end members Phlogopite KMg 3 Al Si 3 O 10 (OH) 2 and Annite KFe 3 Al Si 3 O 10 (OH) 2, although pure Annite does not occur in nature. In addition, small amounts of Na, Rb, Cs, and Ba may substitute for K, and like in other minerals, F can substitute for OH and increase the stability of Biotite to higher temperatures and pressures. Occurrence - Nearly pure phlogopite is found in hydrous ultrabasic rocks like kimberlite, and is also found in metamorphosed dolomites. Biotite, with more Fe-rich compositions is common in dacitic, rhyolitic, and trachytic volcanic rocks, granitic plutonic rocks, and a wide variety of metamorphic rocks. In metamorphic rocks, biotite usually shows a preferred orientation with its {001} forms parallel to the schistose foliation. Properties - In hand specimen, Biotite is brown to black and shows the perfect {001} micaceous cleavage. In thin section, it shows the perfect cleavage and mottled extinction typical of all micas. It's most characteristic property is its pleochroism, showing yellow to brown to green colors. Hornblende shows similar pleochroic colors, but is distinguished from biotite by the differences in cleavage of the 2 minerals. Biotite is biaxial negative with a low 2V of 0 o to 25 o. Chlorite Group As discussed above, the Chlorite group has a structure that consists of phlogopite T-O-T layers sandwiching brucite-like octahedral layer. There is substantial substitution of Mg for Fe, and Al can substitute for (Mg, Fe) in both the octahedral sites, as well as for Si in the tetrahedral sites. Thus, chlorite can have a rather complicated formula - (Mg,Fe,Al) 3 (Si,Al) 4 O 10 (OH) 6 . Occurrence- Chlorite is a common mineral in low grade metamorphic rocks, where it occurs in association with minerals like actinolite, epidote, and biotite. It also forms as an alteration product of pyroxenes, amphiboles, biotite, and garnet in igneous as well a metamorphic rocks. Properties - In hand specimen, chlorite is recognized by its green color, micaceous habit and cleavage, and association with other minerals like actinolite and epidote. In thin section, Chlorite shows low relief and low birefringence, with a characteristic midnight blue to black anomalous interference color. It shows some pleochroism in the range of green to pale yellow. It is easily distinguished from biotite by its lower relief and anomalous interference color. Examples of questions on this material that could be asked on an exam (note that properties that distinguish different minerals will be included in the laboratory exam)What is the difference between the dioctahedral and trioctahedral sheet silicates? What is the difference between antigorite and chrysotile? State whether each of the following minerals would be most commonly found in igneous rocks, metamorphic rocks, or both igneous and metamorphic rocks: (a) Chlorite, (b) biotite, (c) muscovite, (d) talc, (e) serpentine,Return to EENS 2110 Page  lithology lithology (redirected from petrology) Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia. Related to petrology: igneous petrology, sedimentary petrologylithology (lĭth-ŏl′ō-jē) [″ + logos, word, reason]The science dealing with calculi. Medical Dictionary, © 2009 Farlex and Partners Want to thank TFD for its existence? Tell a friend about us, add a link to this page, or visit the webmaster's page for free fun content . Link to this page:<a href="https://medical-dictionary.thefreedictionary.com/petrology">lithology</a>Facebook Twitter  Large igneous province From Wikipedia, the free encyclopedianavigation search Only a few of the largest large igneous provinces appear (coloured dark purple) on this geological map, which depicts crustal geologic provinces as seen in seismic refraction data. In geology, a large igneous province (LIP) is an extremely large accumulation of igneous rocks, including plutonic rocks ( intrusive) or volcanic rock formations ( extrusive ), arising when hot magma extrudes from inside the Earth and flows out. The source of many or all LIPs is variously attributed to mantle plumes or to processes associated with plate tectonics. [1] Types of LIPs can include large volcanic provinces (LVP), created through flood basalt, and large plutonic provinces (LPP). [2] Michael Rampino and Richard Stothers (1988) cited eleven distinct flood-basalt episodes - occurring in the past 250 million years - which created volcanic provinces and plateaus and coincided with mass extinctions. [3] However, more flood basalts have been recognized, such as the large Ontong Java Plateau, [4] and the medium-sized Chilcotin Group, though the latter may be linked to the Columbia River Basalt Group. Formation depends on a range of factors, such as continental configuration, latitude, volume, rate, duration of eruption, style and setting (continental vs. oceanic), the pre-existing climate state, and the biota resilience to change. [5]Contents [ hide ]1 Definition1.1 Types2 Motivations for study of LIPs3 Large igneous province formation3.1 Formation characteristics3.2 Formation theories3.2.1 Plume formation of LIPs3.2.2 Plate-related stress formation of LIPs3.2.3 Early formed reservoir outpourings3.2.4 Meteorite-induced formation4 Classification5 Correlations with LIP formation5.1 Correlation with hot-spots5.2 Relationship to extinction events5.3 Ore deposits6 Examples6.1 Large rhyolitic provinces (LRPs)6.2 Large Andesitic Provinces (LAPs)6.3 Large basaltic provinces (LBPs)6.3.1 Continental flood basalts6.3.2 Oceanic flood basalts/ oceanic plateaus6.4 Large basaltic–rhyolitic provinces (LBRPs)6.5 Large plutonic provinces (LPP)6.5.1 Large granitic provinces (LGP)6.5.2 Other large plutonic provinces6.6 Related structures6.6.1 Volcanic rifted margins6.6.2 Dike swarms6.6.3 Sills7 See also8 References9 Related reading10 External links Definition [ edit]In 1992 researchers first used the term large igneous province to describe very large accumulations—areas greater than 100,000 square kilometers (approximately the area of Iceland)—of mafic igneous rocks that were erupted or emplaced at depth within an extremely short geological time interval: a few million years or less. [6] Mafic, basalt sea floors and other geological products of 'normal' plate tectonics were not included in the definition. [7]Types [ edit]The definition of LIP has been expanded and refined, and is still a work in progress. LIP is now frequently also used to describe voluminous areas of, not just mafic, but all types of igneous rocks. Sub-categorization of LIPs into large volcanic provinces (LVP) and large plutonic provinces (LPP), and including rocks produced by normal plate tectonic processes, has been proposed. [2]Some LIPs are now intact, such the basaltic Deccan Traps in India, while others have been dismembered by plate tectonic motion, like the basaltic Central Atlantic Magmatic Province (CAMP)—parts of which are found in Brazil, eastern North America, and north-western Africa. Motivations for study of LIPs [ edit]Map showing the recognized continental large igneous provinces. Large igneous provinces (LIPs) are created during short-lived igneous events resulting in relatively rapid and high-volume accumulations of volcanic and intrusive igneous rock. These events warrant study because: The study of LIPs has economic implications. Some workers associate them with trapped hydrocarbons. [ citation needed] They are associated with economic concentrations of copper–nickel and iron. [8] They are also associated with formation of major mineral provinces including Platinum-Group Element (PGE) Deposits, and in the Silicic LIPs, silver and gold deposits. [7] Titanium and vanadium deposits are also found in association with LIPs. [9]Future LIP events may pose a hazard to human civilization. LIPs in the geological record have marked major changes in the hydrosphere and atmosphere, leading to major climate shifts and maybe mass extinctions of species. [7]Plate tectonic theory explains topography using interactions between the tectonic plates, as influenced by viscous stresses created by flow within the underlying mantle. Since the mantle is extremely viscous, the mantle flow rate varies in pulses which are reflected in the lithosphere by small amplitude, long wavelength undulations. Understanding how the interaction between mantle flow and lithosphere elevation influences formation of LIPs is important to gaining insights into past mantle dynamics. [10]LIPs have played a major role in continental breakup, continental formation, new crustal additions from the upper mantle, and supercontinent cycles. [10]Large igneous province formation [ edit]Three Devil's grade in Moses Coulee, Washington is part of the Columbia River Basalt Group LIP. Earth has an outer shell made of a number of discrete, moving tectonic plates floating on a solid convective mantle above a liquid core. The mantle's flow is driven by the descent of cold tectonic plates during subduction and the complementary ascent of plumes of hot material from lower levels. The surface of the Earth reflects stretching, thickening and bending of the tectonic plates as they interact. [11]Ocean-plate creation at upwellings, spreading and subduction are well accepted fundamentals of plate tectonics, with the upwelling of hot mantle materials and the sinking of the cooler ocean plates driving the mantle convection. In this model, tectonic plates diverge at mid-ocean ridges, where hot mantle rock flows upward to fill the space. Plate-tectonic processes account for the vast majority of Earth's volcanism. [12]Beyond the effects of convectively driven motion, deep processes have other influences on the surface topography. The convective circulation drives up-wellings and down-wellings in Earth's mantle that are reflected in local surface levels. Hot mantle materials rising up in a plume can spread out radially beneath the tectonic plate causing regions of uplift. [11] These ascending plumes play an important role in LIP formation. Formation characteristics [ edit]When created, LIPs often have an areal extent of a few million km² and volumes on the order of 1 million km³. In most cases, the majority of a basaltic LIP's volume is emplaced in less than 1 million years. One of the conundra of such LIPs' origins is to understand how enormous volumes of basaltic magma are formed and erupted over such short time scales, with effusion rates up to an order of magnitude greater than mid-ocean ridge basalts. Formation theories [ edit]The source of many or all LIPs are variously attributed to mantle plumes, to processes associated with plate tectonics or to meteorite impacts. Plume formation of LIPs [ edit]Although most of volcanic activity on Earth is associated with subduction zones or mid-oceanic ridges, there are significant regions of long-lived, extensive volcanism, known as hot spots, which are only indirectly related to plate tectonics. The Emperor Sea Mount chain, located on the Pacific plate, is one example, tracing millions of years of relative motion as the plate moves over the Hawaiian hot spot. Numerous hot spots of varying size and age have been identified across the world. These hot spots move slowly with respect to one another, but move an order of magnitude more quickly with respect to tectonic plates, providing evidence that they are not directly linked to tectonic plates. [12]The origin of hotspots remains controversial. Hotspots that reach the Earth’s surface may have three distinct origins. The deepest probably originate from the boundary between the lower mantle and the core; roughly 15–20% have characteristics such as presence of a linear chain of sea mounts with increasing ages, LIPs at the point of origin of the track, low shear wave velocity indicating high temperatures below the current location of the track, and ratios of He 3 to He 4 which are judged consistent with a deep origin. Others such as the Pitcairn, Samoan and Tahitian hotspots appear to originate at the top of large, transient, hot lava domes (termed superswells) in the mantle. The remainder appear to originate in the upper mantle and have been suggested to result from the breakup of subducting lithosphere. [13]Recent imaging of the region below known hot spots (e.g., Yellowstone and Hawaii) using seismic-wave tomography has produced mounting evidence that supports relatively narrow, deep-origin, convective plumes that are limited in region compared to the large-scale plate tectonic circulation in which they are imbedded. Images reveal continuous, but torturous vertical paths with varying quantities of elevated temperature material, particularly at elevations where crystallographic transformations are predicted to occur. [14]Plate-related stress formation of LIPs [ edit]A major alternative to the plume model is a model in which ruptures are caused by plate-related stresses that fractured the lithosphere, allowing melt to reach the surface from shallow heterogeneous sources. The high volumes of molten material that form the LIPs is postulated to be caused by convection in the upper mantle, which is secondary to the convection driving tectonic plate motion. [15]Early formed reservoir outpourings [ edit]It has been proposed that geochemical evidence supports an early-formed reservoir that survived in the Earth's mantle for about 4.5 billion years. Molten material is postulated to have originated from this reservoir, contributing the Baffin Island flood basalt ~60 million years ago. Basalts from the Ontong Java plateau show similar isotopic and trace element signatures proposed for the early-Earth reservoir. [16]Meteorite-induced formation [ edit]Seven pairs of hotspots and LIPs located on opposite sides of the earth have been noted; analyses indicate this coincident antipodal location is highly unlikely to be random. The hotspot pairs include a large igneous province with continental volcanism opposite an oceanic hotspot. Oceanic impacts of large meteorites are expected to have high efficiency in converting energy into seismic waves. These waves would propagate around the world and reconverge close to the antipodal position; small variations are expected as the seismic velocity varies depending upon the route characteristics along which the waves propagate. As the waves focus on the antipodal position, they put the crust at the focal point under significant stress and are proposed to rupture it, creating antipodal pairs. When the meteorite impacts a continent, the lower efficiency of kinetic energy conversion into seismic energy is not expected to create an antipodal hotspot. [15]A second impact-related model of hotspot and LIP formation has been suggested in which minor hotspot volcanism was generated at large-body impact sites and flood basalt volcanism was triggered antipodally by focused seismic energy [13,14]. This model has been challenged because impacts are generally considered seismically too inefficient [15], and the Deccan Traps of India were not antipodal to, and began erupting several Myr before, the end-Cretaceous Chicxulub impact in Mexico. In addition, no clear example of impact-induced volcanism, unrelated to melt sheets, has been confirmed at any known terrestrial crater. [15]Classification [ edit]In 1992, Coffin and Eldholm initially defined the term "large igneous province" (LIP) as representing a variety of mafic igneous provinces with areal extent >1 x 10 5 km 2 that represented "massive crustal emplacements of predominantly mafic (Mg- and Fe-rich) extrusive and intrusive rock, and originated via processes other than 'normal' seafloor spreading." [17] [18] [19] That original definition included continental flood basalts, oceanic plateaus, large dike swarms (the eroded roots of a volcanic province), and volcanic rifted margins. Most of these LIPs consist of basalt, but some contain large volumes of associated rhyolite (e.g. the Columbia River Basalt Group in the western United States); the rhyolite is typically very dry compared to island arc rhyolites, with much higher eruption temperatures (850 °C to 1000 °C) than normal rhyolites. Since 1992 the definition of 'LIP' has been expanded and refined, and remains a work in progress. Some new definitions of the term 'LIP' include large granitic provinces such as those found in the Andes Mountains of South America and in western North America. Comprehensive taxonomies have been developed to focus technical discussions. In 2008, Bryan and Ernst refined the definition to narrow it somewhat: "Large Igneous Provinces are magmatic provinces with areal extents >1 x 10 5 km 2, igneous volumes >1 x 10 5 km 3 and maximum lifespans of ∼50 Myr that have intraplate tectonic settings or geochemical affinities, and are characterised by igneous pulse (s) of short duration (∼1–5 Myr), during which a large proportion (>75%) of the total igneous volume has been emplaced. They are dominantly mafic, but also can have significant ultramafic and silicic components, and some are dominated by silicic magmatism." This definition places emphasis on the high magma emplacement rate characteristics of the LIP event and excludes seamounts, seamount groups, submarine ridges and anomalous seafloor crust. [20]'LIP' is now frequently used to also describe voluminous areas of, not just mafic, but all types of igneous rocks. Sub-categorization of LIPs into Large Volcanic Provinces (LVP) and Large Plutonic Provinces (LPP), and including rocks produced by 'normal' plate tectonic processes, has been proposed. Further, the threshold to be included as a LIP has been lowered to >5x10 4 km 2. [2] The working taxonomy, focused heavily on geochemistry, which will be used to structure examples below, is: Large igneous provinces (LIP)Large volcanic provinces (LVP)Large rhyolitic provinces (LRPs)Large andesitic provinces (LAPs)Large basaltic provinces (LBPs): oceanic, or continental flood basalts Large basaltic–rhyolitic provinces (LBRPs)Large plutonic provinces (LPP)Large granitic provinces (LGP)Large mafic plutonic provinces Illustration showing a vertical dike and a horizontal sill. Aerally extensive dike swarms, sill provinces, and large layered ultramafic intrusions are indicators of LIPs, even when other evidence is not now observable. The upper basalt layers of older LIPs may have been removed by erosion or deformed by tectonic plate collisions occurring after the layer is formed. This is especially likely for earlier periods such as the Paleozoic and Proterozoic. [20]Giant dyke swarms having lengths >300 km [21] are a common record of severely eroded LIPs. Both radial and linear dyke swarm configurations exist. Radial swarms with an areal extent >2000 km and linear swarms extending >1000 km are known. The linear dyke swarms often have a high proportion of dykes relative to country rocks, particularly when the width of the linear field is less than 100 km. The dykes have a typical width of 20–100 meters, although ultramafic dykes with widths greater than 1000 meters have been reported. [20]Dykes are typically sub-vertical to vertical. When upward flowing (dyke-forming) magma encounters horizontal boundaries or weaknesses, such as between layers in a sedimentary deposit, the magma can flow horizontally creating a sill. Some sill provinces have areal extents >1000 km. [20]Correlations with LIP formation [ edit]Correlation with hot-spots [ edit]The early volcanic activity of major hotspots, postulated to result from deep mantle plumes, is frequently accompanied by flood basalts. These flood basalt eruptions have resulted in large accumulations of basaltic lavas emplaced at a rate greatly exceeding that seen in contemporary volcanic processes. Continental rifting commonly follows flood basalt volcanism. Flood basalt provinces may also occur as a consequence of the initial hot-spot activity in ocean basins as well as on continents. It is possible to track the hot spot back to the flood basalts of a large igneous province; the table below correlates large igneous provinces with the track of a specific hot spot. [22] [23]Province Region Hotspot Reference Columbia River Basalt Northwestern USA Yellowstone hotspot [22] [24]Ethiopia-Yemen Flood Basalts Ethiopia, Yemen [22]North Atlantic Igneous Province Northern Canada, Greenland, the Faeroe Islands, Norway, Ireland and Scotland Iceland hotspot [22]Deccan Traps India & southern Pakistan Réunion hotspot [22]Rahjamal Traps Eastern India Ninety East Ridge [25] [26]Kerguelen Plateau Indian Ocean Kerguelen hotspot [25]Ontong-Java Plateau Pacific Ocean Louisville hotspot [22] [23]Paraná and Etendeka traps Brazil – Namibia Tristan hotspot [22]Karoo-Ferrar Province South Africa, Antarctica, Australia & New Zealand Marion Island [22]Caribbean large igneous province Caribbean-Colombian oceanic plateau Galápagos hotspot [27] [28]Mackenzie Large Igneous Province Canadian Shield Mackenzie hotspot [29]Relationship to extinction events [ edit]Eruptions or emplacements of LIPs appear to have, in some cases, occurred simultaneously with oceanic anoxic events and extinction events. The most important examples are the Deccan Traps ( Cretaceous–Paleogene extinction event ), the Karoo-Ferrar ( Pliensbachian-Toarcian extinction ), the Central Atlantic Magmatic Province ( Triassic-Jurassic extinction event ), and the Siberian traps ( Permian-Triassic extinction event ). Several mechanisms are proposed to explain the association of LIPs with extinction events. The eruption of basaltic LIPs onto the earth's surface releases large volumes of sulfate gas, which forms sulfuric acid in the atmosphere; this absorbs heat and causes substantial cooling (e.g., the Laki eruption in Iceland, 1783). Oceanic LIPs can reduce oxygen in seawater by either direct oxidation reactions with metals in hydrothermal fluids or by causing algal blooms that consume large amounts of oxygen. [30]Ore deposits [ edit]Large igneous provinces are associated with a handful of ore deposit types including: Ni – Cu PGEs Porphyries Iron oxide copper gold (IOCG)Kimberlites Examples [ edit]See also: World's largest eruptions There are a number of well documented examples of large igneous provinces identified by geological research. Province Region Age ( Ma)Area (10 6 km 2Volume (10 6 km 3Also known as or includes Reference Agulhas Plateau Southwest Indian Ocean, South Atlantic Ocean, Southern Ocean 140-95 0.3 1.2 Southeast African LIP Mozambique Ridge, Northeast Georgia Rise, Maud Rise, Astrid Ridge [31]Columbia River Basalt Northwestern US 17–6 0.16 0.175 [24] [32]Ethiopia-Yemen Flood Basalts Yemen, Ethiopia 31–25 0.6 0.35 Ethiopia [32]North Atlantic Igneous Province Northern Canada, Greenland, the Faeroe Islands, Norway, Ireland, and Scotland 62–55 1.3 6.6 High Arctic Large Igneous Province Jameson Land Thulean Plateau [32]Deccan Traps India, southern Pakistan 66 0.5–0.8 0.5–1.0 [32]Madagascar 88 [33]Rajmahal Traps 116 [25] [26]Ontong-Java Plateau Pacific Ocean ~122 1.86 8.4 Manihiki Plateau and Hikurangi Plateau [32]Paraná and Etendeka traps Brazil, Namibia 134–129 1.5 >1 Equatorial Atlantic Magmatic Province Brazilian Highlands [32]Karoo-Ferrar Province South Africa, Antarctica, Australia, and New Zealand 183–180 0.15–2 0.3 [32]Central Atlantic magmatic province Northern South America, Northwest Africa, Iberia, Eastern North America 199–197 11 2.5 (2.0 – 3.0) [34] [35]Siberian Traps Russia 250 1.5–3.9 0.9–2.0 [32]Emeishan Traps Southwestern China 253–250 0.25 ~0.3 [32]Warakurna large igneous province Australia 1078–1073 1.5Eastern Pilbara [36]Large rhyolitic provinces (LRPs) [ edit]These LIPs are composed dominantly of felsic materials. Examples include: Whitsunday Sierra Madre Occidental (Mexico)Malani Chon Aike (Argentina)Gawler (Australia)Large Andesitic Provinces (LAPs) [ edit]These LIPs are comprised dominantly of andesitic materials. Examples include: Island arcs such as Indonesia and Japan Active continental margins such as the Andes and the Cascades Continental collision zones such as the Anatolia-Iran zone Large basaltic provinces (LBPs) [ edit]This subcategory includes most of the provinces included in the original LIP classifications. It is composed of continental flood basalts, oceanic flood basalts, and diffuse provinces. Continental flood basalts [ edit]Ethiopia-Yemen Continental Flood Basalts Columbia River Basalt Group Deccan Traps (India)Coppermine River Group (Canadian Shield)Equatorial Atlantic Magmatic Province ( Maranhão, Brazil-Ghana)Midcontinent Rift System, Great Lakes Region, North America Paraná and Etendeka traps ( Paraná, Brazil–NE Namibia)Brazilian Highlands Río de la Plata Craton (Uruguay)Karoo-Ferrar (South Africa–Antarctica)Siberian Traps (Russia)Emeishan Traps (western China)Central Atlantic Magmatic Province (eastern United States and Canada, northern South America, northwest Africa)North Atlantic Igneous Province (includes basalts in Greenland, Iceland, Ireland, Scotland, and Faroes)High Arctic Large Igneous Province (includes the Ellesmere Island Volcanics, Strand Fiord Formation, Alpha Ridge, Franz Josef Land, and Svalbard)Oceanic flood basalts/ oceanic plateaus [ edit]Wrangellia Terrane (Alaska and Canada)Caribbean large igneous province (Caribbean Sea)Kerguelen Plateau (Indian Ocean)Ontong Java Plateau, Manihiki Plateau and Hikurangi Plateau (southwest Pacific Ocean)Jameson Land Large basaltic–rhyolitic provinces (LBRPs) [ edit]Snake River Plain – Oregon High Lava Plains Dongargarh (Ethiopia)Large plutonic provinces (LPP) [ edit]Large granitic provinces (LGP) [ edit]Patagonia Peru–Chile Batholith Coast Range Batholith (NW US)Other large plutonic provinces [ edit]Parts of Central Atlantic Magmatic Province (eastern United States and Canada, northern South America, northwest Africa)Related structures [ edit]Volcanic rifted margins [ edit]Extension thins the crust. Magma reaches the surface through radiating sills and dikes, forming basalt flows, as well as deep and shallow magma chambers below the surface. The crust gradually thins due to thermal subsidence, and originally horizontal basalt flows are rotated to become seaward dipping reflectors. Volcanic rifted margins are found on the boundary of large igneous provinces. Volcanic margins form when rifting is accompanied by significant mantle melting, with volcanism occurring before and/or during continental breakup. Volcanic rifted margins are characterized by: a transitional crust composed of basaltic igneous rocks, including lava flows, sills, dikes, and gabbros, high volume basalt flows, seaward-dipping reflector sequences (SDRS) of basalt flows that were rotated during the early stages of breakup, limited passive-margin subsidence during and after breakup, and the presence of a lower crust with anomalously high seismic P-wave velocities in lower crustal bodies (LCBs), indicative of lower temperature, dense media. Example of volcanic margins include: The Yemen margin The East Australian margin The West Indian margin The Hatton–Rockal margin The US East Coast The mid-Norwegian margin The Brazilian margins The Namibian margin Dike swarms [ edit]Map of the Mackenzie dike swarm in Canada A dike swarm is a large geological structure consisting of a major group of parallel, linear, or radially oriented dikes intruded within continental crust. They consist of several to hundreds of dikes emplaced more or less contemporaneously during a single intrusive event, and are magmatic and stratigraphic. Such dike swarms are the roots of a volcanic province. Examples include: Mackenzie dike swarm (Canadian Shield)Long Range dikes (Newfoundland and Labrador, Canada)Mistassini dike swarm (western Quebec, Canada)Matachewan dike swarm (northern Ontario, Canada)Sorachi Plateau and Belt (Hokkaido, Japan)Uralian dike swarm (Russia) [37]Sills [ edit]A series of related sills that were formed essentially contemporaneously (within several million years) from related dikes comprise a LIP if their area is sufficiently large. Examples include: Winagami sill complex (northwestern Alberta, Canada)Bushveld Igneous Complex (South Africa) with an area of over 66,000 km 2 (25,000 sq mi), and a thickness reaching 9 kilometres (5.6 mi) thick. 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Marsh, JS; Hooper, PR; Rehacek, J; Duncan, RA; Duncan, AR (1997). "Stratigraphy and age of Karoo basalts of Lesotho and implications for correlations within the Karoo igneous province". In Mahoney JJ and Coffin MF. Large Igneous Provinces: continental, oceanic, and planetary flood volcanism. Geophysical Monograph. 100. Washington, DC: American Geophysical Union. pp. 247–272. ISBN 0-87590-082-8. Peate, DW (1997). Mahoney JJ and Coffin MF, eds. "Large Igneous Provinces: continental, oceanic, and planetary flood volcanism". Geophysical Monograph. 100. Washington, DC: American Geophysical Union: 247–272. ISBN 0-87590-082-8. |chapter= ignored ( help)Ratajeski, K. (25 November 2005). "The Cretaceous Superplume". Ritsema, J.; van Heijst, H. J.; Woodhouse, J. H. (1999). "Complex shear wave velocity structure imaged beneath Africa and Iceland". Science. 286 (5446): 1925–1928. doi: 10.1126/science.286.5446.1925. PMID 10583949. Saunders, AD (December 2005). "Large igneous provinces: origin and environmental consequences". Elements. 1 (5): 259–263. doi: 10.2113/gselements.1.5.259. Segev, A (2002). "Flood basalts, continental breakup and the dispersal of Gondwana: evidence for periodic migration of upwelling mantle flows (plumes)" (PDF). EGU Stephan Mueller Special Publication Series. 2: 171–191. doi: 10.5194/smsps-2-171-2002. Retrieved 5 August 2010. Wignall, P (December 2005). "The link between large igneous provinces eruptions and mass extinctions". Elements. 1 (5): 293–297. doi: 10.2113/gselements.1.5.293. External links [ edit]Large Igneous Provinces Commissionwww. Mantle Plumes.org [ hide]v t e Large igneous provinces Agulhas Plateau ( Northeast Georgia Rise, Maud Rise) Brazilian Highlands Caribbean Central Atlantic Circum-Superior Columbia River Deccan Emeishan Ethiopian and Yemen Highlands Franklin ( Franklin dike swarm) High Arctic ( Sverdrup Basin) Karoo-Ferrar Kerguelen ( Broken Ridge) Marathon Keweenawan Long Range Mackenzie ( Coppermine River Mackenzie dike swarm) Matachewan Mistassini North Atlantic Ontong Java - Manihiki - Hikurangi Panjal Paraná and Etendeka Shatsky Siberian Skagerrak Ungava Winagami Categories: Igneous rocks Petrology Volcanology Flood basalts Geological hazards Supervolcanoes Large igneous provinces Geomorphology Orogeny Climate forcing agents 