Orogenic belt

An '''orogenic belt''', '''orogen''', or '''mobile belt'''{{efn|The term ''mobile belt'' is sometimes preferred for orogenic belts to which plate-tectonic models cannot be applied as easily due to their age.<ref>{{Cite web |title=mobile belt |url=https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/mobile-belt |access-date=2022-12-26 |website=www.encyclopedia.com |publisher=Oxford University Press}}</ref>}} is a zone of Earth's crust affected by orogeny.<ref>{{Cite web|title=Orogenic belt {{!}} geology|url=https://www.britannica.com/science/orogenic-belt|access-date=2021-04-29|website=Encyclopedia Britannica|language=en}}</ref> An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collectively called ''orogenesis''.<ref name="Waltham">{{cite book|author=Tony Waltham|url=https://books.google.com/books?id=JGtIHJTXaI4C&pg=PA20|title=Foundations of Engineering Geology|date=2009|publisher=Taylor & Francis|isbn=978-0-415-46959-3|edition=3rd|page=20 |doi=10.1201/9781315273488 }}</ref><ref name="Vine">{{cite book|author=Philip Kearey|title=Global Tectonics|author2=Keith A. Klepeis|author3=Frederick J. Vine|date=2009|publisher=Wiley-Blackwell|isbn=978-1-4051-0777-8|edition=3rd|page=287|chapter=Chapter 10: Orogenic belts|chapter-url=https://books.google.com/books?id=HYqZntfg25UC&pg=PA287}}</ref> == Overview == Orogeny typically produces ''orogenic belts'', which are elongated regions of deformation bordering continental cratons. Young orogenic belts, in which subduction is still taking place, are characterized by frequent volcanic activity and earthquakes. Older orogenic belts are typically deeply eroded to expose displaced and deformed strata. These are often highly metamorphosed and include vast bodies of intrusive igneous rock called batholiths.<ref name=":0">{{cite book |last1=Donaldson |first1=Colin H. |last2=Reavy |first2=R.John |last3=O'Mahony |first3=Michael John |title=Encyclopedia of Physical Science and Technology |chapter=Plutonic Geology |date=2003 |pages=491–508 |doi=10.1016/B0-12-227410-5/00588-3 |isbn=978-0-12-227410-7 }}</ref> <gallery widths="250" heights="250" mode="nolines"> File:Active Margin.svg|Subduction of an oceanic plate beneath a continental plate to form an accretionary orogen. (example: the Andes) File:Continental-continental convergence Fig21contcont.gif|Continental collision of two continental plates to form a collisional orogen. Typically, continental crust is subducted to lithospheric depths for blueschist to eclogite facies metamorphism, and then exhumed along the same subduction channel. (example: the Himalayas)

</gallery> Orogenic belts are associated with subduction zones, which consume crust, thicken lithosphere, produce earthquake and volcanoes, and often build island arcs. These island arcs may be added to a continental margin during an accretionary orogeny. The orogeny may culminate with continental crust from the opposite side of the subducting oceanic plate arriving at the subduction zone. This ends subduction and transforms the accretional orogeny into a collisional orogeny. The collisional orogeny may produce extremely high mountains, as has been taking place in the Himalayas for the last 65 million years.<ref name=":0" />{{clarify |reason=65 million does not appear at least in the online part of the cited source (though I don't know about its offline part). And our Himalayas article says the collision began 40 to 50 million years ago, not 65 million. And 65 million, especially if incorrect, may misleadingly suggest to some readers some sort of connection to the extinction of the dinosaurs around that time.|date=March 2022}}

<gallery widths="240" heights="240" mode="nolines"> File:Pacific Ring of Fire.png|Circum-Pacific orogenic belt<br> (Pacific Ring of Fire) File:Alpiner Gebirgsgürtel.png|Alpine-Himalayan orogenic belt </gallery>

Prominent orogenic belts on the Earth are the circum-Pacific orogenic belt (the Pacific Ring of Fire) and the Alpine-Himalayan orogenic belt.<ref name=":0" /> Since these orogenic belts are young, they form large mountain ranges; crustal activity is active and accompanied by volcanic belts and seismic belts.<ref>{{Cite web|title=Ring of Fire {{!}} Definition, Map, & Facts|url=https://www.britannica.com/place/Ring-of-Fire|access-date=2021-04-29|website=Encyclopedia Britannica|language=en}}</ref>

== Notes == {{notelist}}

== References == <references />

==External links== {{Commons category-inline}}

Category:Belt regions * Category:Plate tectonics Category:Mountain geomorphology Category:Effects of gravity