{{Short description|Geological processes that underlie the formation of mountains}} {{For|the mountain-building process that takes place at a convergent plate margin|Orogeny}}
[[File:Mountain by reverse fault.gif|thumb|Thrust and reverse fault movement are an important component of mountain formation.]] [[File:Lewis overthrust fault nh10f.jpg|thumb|Illustration of mountains that developed on a fold that thrusted.]]
'''Mountain formation''' occurs due to a variety of geological processes associated with large-scale movements of Earth's crust (tectonic plates).<ref name="Stanley">{{cite book |title=Earth system history |author=Steven M. Stanley |chapter-url=https://books.google.com/books?id=jd01mugCR7EC&pg=PA207 |page=207 |chapter=Mountain building |isbn=978-0-7167-3907-4 |date=2004 |edition=2nd |publisher=Macmillan}}</ref> Folding, faulting, volcanic activity, igneous intrusion and metamorphism can all be parts of the orogenic process of mountain building.<ref name="Twiss">{{cite book |title=Structural Geology |author=Robert J. Twiss |author2=Eldridge M. Moores |chapter=Plate tectonic models of orogenic core zones |page=[https://archive.org/details/structuralgeolog0000twis/page/493 493] |isbn=978-0-7167-2252-6 |date=1992 |edition=2nd |publisher=Macmillan |chapter-url=https://books.google.com/books?id=14fn03iJ2r8C&pg=PA493 |url=https://archive.org/details/structuralgeolog0000twis/page/493 }}</ref> The formation of mountains is not necessarily related to the geological structures found on it.<ref>{{cite book |last1=Ollier |first1=Cliff|last2=Pain |first2=Colin |date=2000|author-link1=Cliff Ollier |title=The Origin of Mountains |url=https://archive.org/details/originmountains00olli|url-access=limited |publisher=Routledge |page=[https://archive.org/details/originmountains00olli/page/n22 1] |isbn=978-0-415-19890-5}}</ref>
From the late 18th century until its replacement by plate tectonics in the 1960s, geosyncline theory was used to explain much mountain-building.<ref>{{cite web |url=https://publish.illinois.edu/platetectonics/geosynclinal-theory/ |title=Geosynclinal Theory |website=publish.illinois.edu |publisher=University of Illinois at Urbana-Champaign |access-date=March 8, 2018|quote=The major mountain-building idea that was supported from the 19th century and into the 20th is the geosynclinal theory.}}</ref> The understanding of specific landscape features in terms of the underlying tectonic processes is called ''tectonic geomorphology'', and the study of geologically young or ongoing processes is called ''neotectonics''.<ref name=Stuwe>{{cite book |title=Geodynamics of the lithosphere: an introduction |author= Kurt Stüwe |chapter=§4.5 Geomorphology |chapter-url=https://books.google.com/books?id=gwYcuMSUnxEC&pg=PA178 |page=178 |isbn=978-3-540-71236-7 |date=2007 |publisher=Springer |edition=2nd}}</ref>{{clarify|date=January 2017}}
==Types of mountains== {{See also|List of mountain types}} There are five main types of mountains: '''volcanic''', '''fold''', '''plateau''', '''fault-block''', and '''dome'''. A more detailed classification useful on a local scale predates plate tectonics and adds to these categories.<ref name=Goudie>{{cite book |author=Andrew Goudie |title=Encyclopedia of geomorphology; Volume 2 |url=https://books.google.com/books?id=UHRU_6nUSR4C&pg=PA701 |page=701 |isbn=978-0-415-32738-1 |date=2004 |publisher=Routledge}}</ref>
===Volcanic mountains=== {{See also|Guyot}} [[File:ISS-38 Kliuchevskoi Volcano on Kamchatka.jpg|thumb|right|400px|Annotated view includes Ushkovsky, Tolbachik, Bezymianny, Zimina, and Udina stratovolcanoes of Kamchatka, Russia. Oblique view taken on November 12, 2013, from ISS.<ref>[http://earthobservatory.nasa.gov/IOTD/view.php?id=82471 NASA - Activity at Kliuchevskoi]</ref>]]
Movements of tectonic plates create volcanoes along the plate boundaries, which erupt and form mountains. A ''volcanic arc system'' is a series of volcanoes that form near a subduction zone where the crust of a sinking oceanic plate melts and drags water down with the subducting crust.<ref name=Butz>{{cite book |title=Science of Earth Systems |author=Stephen D Butz |chapter-url=https://books.google.com/books?id=JB4ArbvXXDEC&pg=PA136 |page=[https://archive.org/details/isbn_9780766833913/page/136 136] |chapter=Chapter 8: Plate tectonics |isbn=978-0-7668-3391-3 |date=2004 |publisher=Thompson/Delmar Learning |url=https://archive.org/details/isbn_9780766833913/page/136 }}</ref> [[File:Sofia-vitosha-kempinski.jpg|right|300px|thumb|The Dome of Vitosha mountain next to Sofia]] Most volcanoes occur in a band encircling the Pacific Ocean (the Pacific Ring of Fire), and in another that extends from the Mediterranean across Asia to join the Pacific band in the Indonesian Archipelago. The most important types of volcanic mountain are ''composite cones'' or ''stratovolcanoes'' and ''shield volcanoes''.<ref name=Gerrard1>{{cite book |title=Mountain environments: an examination of the physical geography of mountains |chapter=Types of volcano |page=[https://archive.org/details/mountainenvironm0000gerr/page/194 194] |chapter-url=https://books.google.com/books?id=jHnrVEyMhkQC&pg=PA194 |isbn=978-0-262-07128-4 |date=1990 |publisher=MIT Press |author=John Gerrard |url=https://archive.org/details/mountainenvironm0000gerr/page/194 }}</ref><ref name=Decker>{{cite book |title=Volcanoes |author= Robert Wayne Decker |author2=Barbara Decker |chapter-url=https://books.google.com/books?id=BilBFXIW5c4C&pg=PA113 |chapter=Chapter 8: Hot spots |isbn=978-0-7167-8929-1 |edition=4th |date=2005 |publisher=Macmillan |page=113 ''ff''}} </ref>
A shield volcano has a gently sloping cone because of the low viscosity of the emitted material, primarily basalt. Mauna Loa is the classic example, with a slope of 4°-6°. (The relation between slope and viscosity falls under the topic of angle of repose.<ref name=Holmes&Duff>{{cite book |title=Holmes Principles of Physical Geology |publisher=Taylor & Francis |date=2004 |edition=4th |author=Arthur Holmes |author-link = Arthur Holmes|author2=Donald Duff |author-link2 = Donald Duff (geologist and author)|url=https://books.google.com/books?id=E6vknq9SfIIC&pg=PT226 |page=209 |isbn=978-0-7487-4381-0 }}</ref>) A composite volcano or stratovolcano has a more steeply rising cone (33°-40°),<ref name=transactions>{{cite book |title=Transactions of the American Society of Civil Engineers, Volume 39 |url=https://books.google.com/books?id=ZlNDAAAAYAAJ&pg=PA62 |page=62 |date=1898 |publisher=American Society of Civil Engineers}}</ref> because of the higher viscosity of the emitted material, and eruptions are more violent and less frequent than for shield volcanoes. Examples include Vesuvius, Kilimanjaro, Mount Fuji, Mount Shasta, Mount Hood and Mount Rainier.<ref name=Todd>{{cite book |title=An Introduction to Physical Science |author=James Shipman |author2=Jerry D. Wilson |author3=Aaron Todd |chapter-url=https://books.google.com/books?id=1LvMLoaN0HQC&pg=PT670 |page=650 |chapter=Minerals, rocks and volcanoes |isbn=978-0-618-93596-3 |date=2007 |publisher=Cengage Learning |edition =12th}}</ref>
===Fold mountains=== {{See also|Fold mountain|Fold and thrust belt}} [[File:Kolunchin Zardkuh.JPG|thumb|Zard-Kuh, a fold mountain in the central Zagros range of Iran.]] When plates collide or undergo subduction (that is, ride one over another), the plates tend to buckle and fold, forming mountains. While volcanic arcs form at oceanic-continental plate boundaries, folding occurs at continental-continental plate boundaries. Most of the major continental mountain ranges are associated with thrusting and folding or orogenesis. Examples are the Balkan Mountains, the Jura and the Zagros mountains.<ref name=Hatcher>{{cite book |title=4-D framework of continental crust |editor=Robert D Hatcher Jr. |editor2=MP Carlson | editor3=JH McBride & JR Martinez Catalán |author=Michael P Searle |page=41 ''ff'' |chapter-url=https://books.google.com/books?id=jD-zXhTfJuMC&pg=PA41 |chapter=Diagnostic features and processes in the construction and evolution of Oman-, Zagros-, Himalayan-, Karakoram-, and Tibetan type orogenic belts |isbn=978-0-8137-1200-0 |publisher=Geological Society of America |date=2007}}</ref>
===Block mountains=== thumb|Fault-block mountain of the tilted type.<ref name=Park>{{cite book |title=The environment: principles and applications |author=Chris C. Park |chapter=Figure 6.11 |page=160 |chapter-url=https://books.google.com/books?id=Ew3MBjbw4OAC&pg=PA160 |date=2001 |edition=2nd |publisher=Routledge|isbn=9780415217705 }}</ref> [[File:Sierra Nevada Mountains.JPG|thumb|Sierra Nevada Mountains (formed by delamination) as seen from the International Space Station.]] When a fault block is raised or tilted, a block mountain can result.<ref name=Ryan>{{cite book |title=CliffsQuickReview Earth Science |chapter-url=https://books.google.com/books?id=PV_BabxTTkcC&pg=PA94 |chapter=Figure 13-1 |author=Scott Ryan |isbn=978-0-471-78937-6 |date=2006 |publisher=Wiley |url=https://archive.org/details/cliffsquickrevie0000ryan }}</ref> Higher blocks are called ''horsts,'' and troughs are called ''grabens''. A spreading apart of the surface causes tensional forces. When the tensional forces are strong enough to cause a plate to split apart, it does so such that a center block drops down relative to its flanking blocks.
An example is the Sierra Nevada range, where delamination created a block 650 km long and 80 km wide that consists of many individual portions tipped gently west, with east facing slips rising abruptly to produce the highest mountain front in the continental United States.<ref name=Gerrard2>{{cite book |title=Reference cited |url=https://books.google.com/books?id=jHnrVEyMhkQC&pg=PA9 |page=9 |author=John Gerrard |isbn=978-0-262-07128-4 |date=1990-04-12 }}</ref><ref name="delamination_lee">{{cite journal|doi=10.1126/science.289.5486.1912|pmid=10988067|title=Osmium Isotopic Evidence for Mesozoic Removal of Lithospheric Mantle Beneath the Sierra Nevada, California|first5=SB|last5=Jacobsen|first4=JT|last4=Chesley|first3=RL|last3=Rudnick|first2=Q|date=2000|last2=Yin|last1=Lee|first1=C.-T.|journal=Science|volume=289|issue=5486|pages=1912–6|url=http://www.geol.umd.edu/~rudnick/Webpage/Lee_2000_Science.pdf|bibcode=2000Sci...289.1912L|url-status=dead|archive-url=https://web.archive.org/web/20110615170551/http://www.geol.umd.edu/~rudnick/Webpage/Lee_2000_Science.pdf|archive-date=2011-06-15}}</ref>
Another example is the Rila–Rhodope massif in Bulgaria, including the well defined horsts of Belasitsa (linear horst), Rila mountain (vaulted domed shaped horst) and Pirin mountain—a horst forming a massive anticline situated between the complex graben valleys of the Struma and Mesta rivers.<ref name="Geographic Dictionary of Bulgaria 368">{{cite book | ref={{harvid|Geographic Dictionary of Bulgaria|1980}} | script-title =bg: Географски речник на България | trans-title = Geographic Dictionary of Bulgaria | last1 = Мичев (Michev) | first1 = Николай (Nikolay) | last2 = Михайлов (Mihaylov) | first2 = Цветко (Tsvetko) | last3 = Вапцаров (Vaptsarov) | first3 = Иван (Ivan) | last4 = Кираджиев (Kiradzhiev) | first4 = Светлин (Svetlin) | year = 1980 | language = bg | publisher = Наука и култура (Nauka i kultura) | location = Sofia |page=368}}</ref><ref name="dimitrova53">{{cite book | ref={{harvid|Dimitrova et al.|2004}} | trans-title = Pirin National Park. Management Plan | script-title= bg:Национален парк "Пирин". План за управление | last1 = Димитрова (Dimitrova) | first1 = Людмила (Lyudmila) | others = и колектив | year = 2004 | language = bg | publisher = Ministry of Environment and Water, Bulgarian Foundation "Biodiversity" | location = Sofia |page=53 }}</ref><ref>{{cite book | ref={{harvid|Donchev|Karakashev|2004}} | script-title=bg: Теми по физическа и социално-икономическа география на България | trans-title=Topics on Physical and Social-Economic Geography of Bulgaria | last1 = Дончев (Donchev) | first1 = Дончо (Doncho) | last2 = Каракашев (Karakashev) | first2 = Христо (Hristo) | year = 2004 | language = bg | publisher = Ciela | location = Sofia | isbn = 954-649-717-7 |pages=128–129}}</ref>
===Uplifted passive margins=== Unlike orogenic mountains there is no widely accepted geophysical model that explains elevated passive continental margins such as the Scandinavian Mountains, eastern Greenland, the Brazilian Highlands, or Australia's Great Dividing Range.<ref>{{cite web |url=http://www.geografitorget.se/gn/nr/2009/bil/1-03.pdf |title=atlantens kustberg och högslätter – gamla eller unga? |last1=Bonow |first1=Johan M. |date=2009 |website=www.geografitorget.se |publisher=Geografilärarnas Riksförening |language=sv}}</ref><ref name=Greenetal2013>{{cite journal |last1=Green |first1=Paul F. |last2=Lidmar-Bergström |first2=Karna |last4=Bonow |first4=Johan M. |last3=Japsen |first3=Peter |last5=Chalmers |first5=James A. |author-link2=Karna Lidmar-Bergström |date=2013 |title=Stratigraphic landscape analysis, thermochronology and the episodic development of elevated, passive continental margins |journal=Geological Survey of Denmark and Greenland Bulletin |volume=30 |pages=18 |doi=10.34194/geusb.v30.4673 |doi-access=free }}</ref> Different elevated passive continental margins most likely share the same mechanism of uplift. This mechanism is possibly related to far-field stresses in Earth's lithosphere. According to this view elevated passive margins can be likened to giant anticlinal lithospheric folds, where folding is caused by horizontal compression acting on a thin to thick crust transition zone (as are all passive margins).<ref>{{cite journal|author-last=Japsen |author-first=Peter |author-last2=Chalmers|author-first2=James A. |author-last3=Green|author-first3=Paul F.|author-last4=Bonow|author-first4=Johan M. |date=2012|title=Elevated, passive continental margins: Not rift shoulders, but expressions of episodic, post-rift burial and exhumation|journal=Global and Planetary Change|volume=90-91|pages=73–86|bibcode=2012GPC....90...73J|doi=10.1016/j.gloplacha.2011.05.004}}</ref><ref>Løseth and Hendriksen 2005</ref>
==Models== {{See also|Extensional tectonics|Rift valley|Rift|Prediction of volcanic activity|Geomorphology}}
===Hotspot volcanoes=== Hotspots are supplied by a magma source in the Earth's mantle called a mantle plume. Although originally attributed to a melting of subducted oceanic crust, recent evidence belies this connection.<ref name=Stoffers>{{cite book |title=Oceanic hotspots: intraplate submarine magmatism and tectonism |author=Y Niu |author2=MJ O'Hara |name-list-style=amp |chapter=Chapter 7: Mantle plumes are NOT from ancient oceanic crust |chapter-url=https://books.google.com/books?id=K7L34ffaODwC&pg=PA239 |page=239 ''ff'' |editor=Roger Hékinian |editor2=Peter Stoffers | editor3=Jean-Louis Cheminée |isbn=978-3-540-40859-8 |date=2004 |publisher=Springer}}</ref> The mechanism for plume formation remains a research topic.
===Fault blocks=== Several movements of Earth's crust that lead to mountains are associated with faults. These movements actually are amenable to analysis that can predict, for example, the height of a raised block and the width of an intervening rift between blocks using the rheology of the layers and the forces of isostasy. Early bent plate models predicting fractures and fault movements have evolved into today's kinematic and flexural models.<ref name=Watts>{{cite book |author=AB Watts |title=Isostasy and flexure of the lithosphere |page=295 |chapter=§7.2 Extensional tectonics and rifting |chapter-url=https://books.google.com/books?id=CNkiZU7enWUC&pg=PA295 |isbn=978-0-521-00600-2 |publisher=Cambridge University Press |date=2001}}</ref><ref name=Weissel>{{cite book |title=Continental tectonics |chapter-url=https://books.google.com/books?id=gpIY2unrObEC&pg=PA271 |author=GD Karner |author2=NW Driscoll |name-list-style=amp |editor=Conall Mac Niocaill |editor2=Paul Desmond Ryan |page=280 |chapter=Style, timing and distribution of tectonic deformation across the Exmouth Plateau, northwest Australia, determined from stratal architecture and quantitative basin modelling |isbn=978-1-86239-051-5 |date=1999 |publisher=Geological society}}</ref>
==See also== *{{annotated link|3D fold evolution}} *{{annotated link|Continental collision}} *{{annotated link|Cycle of erosion}} *{{annotated link|Inselberg}} *{{annotated link|Seamount}}
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==References== {{reflist|33em}}
==External links== *[http://science.gsfc.nasa.gov/698 NASA Goddard Planetary Geodynamics Laboratory] *[https://web.archive.org/web/19961209085431/http://denali.gsfc.nasa.gov/research/volcanology.html NASA Goddard Planetary Geodynamics Laboratory: Volcanology Research] *[https://web.archive.org/web/20100210000748/http://projects.crustal.ucsb.edu/understanding/globe/globe.html Rotating globe showing areas of earthquake activity]
{{earthsinterior}} {{Tectonic plates}}
. . Category:Geological processes Category:Plate tectonics