# Ridge > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Ridge > Markdown URL: https://mediated.wiki/source/Ridge.md > Source: https://en.wikipedia.org/wiki/Ridge > Source revision: 1356633485 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Long, narrow, elevated landform}} {{about|the geography and geology concept}} {{redirect|Ridgeline}} [[File:中橫公路眺望梨山及雪山南稜2.jpg|thumb|The southern ridge of the [Mt Sylvia Range](/source/Xueshan_Range), a ridge composed of several peaks, viewed from the [Lishan](/source/Tri-Mountain_National_Scenic_Area) area of [Taiwan](/source/Taiwan)]] [[File:Tsubakurodake from Otenshodake 2002-8-22.jpg|thumb|A mountain ridge from [Mount Otensho](/source/%3Aja%3A%E5%A4%A7%E5%A4%A9%E4%BA%95%E5%B2%B3) to [Mount Tsubakuro](/source/Mount_Tsubakuro) in Japan]] [[File:The Table1.jpg|thumb|The edges of [tuya](/source/tuya)s can form ridges.]] [[File:Vihren Pirin IMG 0859.jpg|thumb|[Pirin](/source/Pirin) Mountain main ridge – view from [Koncheto](/source/Koncheto) [knife-edge ridge](/source/Ar%C3%AAte) towards the [pyramidal peak](/source/pyramidal_peak)s [Vihren](/source/Vihren) and [Kutelo](/source/Kutelo)]] A '''ridge''' is a long, narrow, [elevated](/source/elevation) [geomorphologic](/source/geomorphology) [landform](/source/landform), [structural feature](/source/Structural_geology), or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the '''crest''' or '''ridgecrest''', with the terrain dropping down on either side. The crest, if narrow, is also called a '''ridgeline'''. Limitations on the dimensions of a ridge are lacking. Its height above the surrounding terrain can vary from less than a meter to hundreds of meters. A ridge can be either [depositional](/source/Deposition_(geology)), [erosion](/source/erosion)al, [tectonic](/source/Tectonics), or a combination of these in origin and can consist of either [bedrock](/source/bedrock), loose [sediment](/source/sediment), [lava](/source/lava), or ice depending on its origin. A ridge can occur as either an isolated, independent feature or part of a larger geomorphological and/or structural feature. Frequently, a ridge can be further subdivided into smaller geomorphic or structural elements.{{cite book | editor-last1=Nystuen | editor-first1=J.P. | title= Rules and recommendations for naming geological units in Norway, Norsk Geologisk Tidsskrift 69, supplement 2 | location= Oslo, Norway | page= 111 | isbn= }}{{cite book | title= Fundamentals of geomorphology |last1=Huggett | first1=R.J. | year=2011 | publisher=Routledge | location=New York, New York | page=516 | isbn=978-0203860083 | edition=3rd |url= |oclc= }}{{cite book | title=Glossary of Geology | publisher=American Geological Institute | editor-last1=Neuendorf | editor-first1=K.K.E. | editor-last2=Mehl | editor-first2=J.P. Jr. | editor-last3=Jackson | editor-first3=J.A. | year=2005 | location=Alexandria, Virginia | page=554 | isbn=978-0922152896| edition=5th }} == Classification == As in the case of landforms in general, there is a lack of any commonly agreed classification or typology of ridges. They can be defined and classified on the basis of a variety of factors including either genesis, morphology, composition, statistical analysis of [remote sensing](/source/remote_sensing) data, or some combinations of these factors. An example of ridge classification is that of Schoeneberger and Wysocki,{{cite web | last1=Schoeneberge | first1=P.J. | last2= Wysocki | first2=D.A. | title=Geomorphic Description System, version 5.0 | publisher=[USDA](/source/USDA) [Natural Resources Conservation Service](/source/Natural_Resources_Conservation_Service) | location=National Soil Survey Center, Lincoln, Nebraska | url=https://www.nrcs.usda.gov/sites/default/files/2022-10/GDS_v5.pdf | pages=25–52 | date=2017 }} which provides a relatively simple and straightforward system that is used by the USA National Cooperative Soil Survey Program to classify ridges and other landforms. This system uses the dominant geomorphic process or setting to classify different groups of landforms into two major groups, ''Geomorphic Environments'' and ''Other Groupings'' with a total of 16 subgroups. The groups and their subgroups are not mutually exclusive; landforms, including ridges, can belong to multiple subgroups. In this classification, ridges are found in the Aeolian, Coastal Marine and Estuarine, Lacustrine, Glacial, Volcanic and Hydrothermal, Tectonic and Structural, Slope, and Erosional subgroups. === Aeolian ridge === ;Aeolian dune ridge: An [aeolian dune ridge](/source/dune) is a ridge of sand piled up by the wind. A sand dune can be either a hill or ridge of sand piled up by the wind. A single sand dune can range in length from less than one meter to several tens of kilometers, their height can vary from a few tens of centimeters to a 150 meters. ''Megadunes'' or ''draas'' are very large dunes, which can have smaller dunes superimposed on them.{{cite book|last1=Pye. |first1=K. |last2=Tsoar. |first2=H. |title= Sand and Sand Dunes |date=2008 |publisher=Springer-Verlag |location=Berlin, Germany |isbn=978-3-540-85909-3 |page=458 |url= |oclc= }} === Coastal ridges === ;Beach ridge: A [beach ridge](/source/beach_ridge) is a low, essentially continuous ridge of beach or beach-and-dune sediments piled up by the action of waves and currents on a shoreline beyond the present limit of storm waves and the reach of ordinary tides. They occur singly or as one of a series of ridges that are roughly parallel to the shoreline. === Erosional ridges === ;[Dendritic](/source/Dendritic_drainage) ridge: In typical [dissected plateau](/source/dissected_plateau) terrain, the stream drainage valleys will leave intervening ridges. These are by far the most common ridges. These ridges usually represent slightly more [erosion](/source/erosion) resistant rock, but not always – they often remain because there were more [joints](/source/Joint_(geology)) where the valleys formed or other chance occurrences. This type of ridge is generally somewhat random in orientation, often changing direction frequently, often with knobs at intervals on the ridge top. thumb|A strike ridge within the Appalachian Mountains ;Strike ridge: A [strike ridge](/source/strike_ridge) is an asymmetric ridge created by the differential erosion of a hard, erosion-resistant, [dipping](/source/Strike_and_dip) layer of rock sandwiched between layers of weaker, more easily eroded rock. A strike ridge has a distinctly gentler sloping side (dip slope), that roughly parallels the inclined layer of erosion-resistant rock. The opposite side of a strike ridge is relatively short, steep or cliff-like slope (scarp slope) that cuts across the tilted layers of rocks. In foldbelts such as the [Ridge-and-Valley Appalachians](/source/Ridge-and-Valley_Appalachians), they form series of long, parallel, straight to arcuate ridges. Strike ridges are subdivided into [cuesta](/source/cuesta)s, [flatirons](/source/Flatiron_(geomorphology)), [homoclinal ridge](/source/homoclinal_ridge)s, and [hogbacks](/source/Hogback_(geology)). ;Reef: A term applied by early explorers and settlers in the western United States to ridges that formed a rocky barrier to land travel, by analogy with ocean [reefs](/source/reefs) as barriers to sea travel. Examples include [Capitol Reef National Park](/source/Capitol_Reef_National_Park){{cite web |url=https://www.nps.gov/care/learn/nature/geology.htm |title=Capitol Reef National Park – Geology |access-date=January 17, 2009 |year=2007 |work=Capitol Reef National Park web site |publisher=U.S. National Park Service }} and the [San Rafael Reef](/source/San_Rafael_Reef). The usage may have originated with sailors during the [Australian gold rushes](/source/Australian_gold_rushes) to describe the gold-bearing ridges of [Bendigo, Australia](/source/Bendigo%2C_Australia).{{cite book |last1=Van Cott |first1=John W. |title=Utah place names : a comprehensive guide to the origins of geographic names : a compilation |date=1990 |publisher=University of Utah Press |location=Salt Lake City, Utah |isbn=9780874803457 |page=65 |url=https://books.google.com/books?id=z3Pqk9tazU4C&q=Reef&pg=PA65 |access-date=2 June 2022}} {{anchor|Reef (geomorphology)}} === Glacial ridges === ;Moraines and eskers: [Glacial](/source/Glacier) activity may leave ridges in the form of [moraine](/source/moraine)s and [esker](/source/esker)s. An [arête](/source/ar%C3%AAte) is a thin ridge of rock that is formed by glacial erosion. ;[Pressure ridge (ice)](/source/Pressure_ridge_(ice)): An ice pressure ridge is a ridge of deformed ice along the boundaries of individual ice floes when the ice floes on a lake or ocean collide and compress their edges. The average height of a sea ice pressure ridge is between 5 and 30 meters.{{cite journal |last1 = Timco |first1 = G.W. |last2 = Burden |first2 = R.P. |title = An analysis of the shapes of sea ice ridges |journal = Cold Regions Science and Technology |volume = 25 |issue = 1|pages = 65–77 |year = 1997 |doi = 10.1016/S0165-232X(96)00017-1|pmid = |pmc = |bibcode = 1997CRST...25...65T }} === Tectonic and Structural ridges === ;[Oceanic spreading ridge](/source/Mid_ocean_ridge): In [tectonic](/source/tectonic) spreading zones around the world, such as at the [Mid-Atlantic Ridge](/source/Mid-Atlantic_Ridge), the volcanic activity forms new land between tectonic boundaries creating volcanic ridges at the spreading zone. [Isostatic](/source/Isostasy) settling and erosion gradually reduces the elevations moving away from the zone. ;[Impact Crater ridge](/source/Impact_crater): Large [asteroid](/source/asteroid) strikes typically form large [impact crater](/source/impact_crater)s bordered by rim(s) that are circular ridge(s).{{cite book |last=French |first=Bevan M |year=1998 |title=[Traces of Catastrophe](/source/Traces_of_Catastrophe): A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures |publisher=[Lunar and Planetary Institute](/source/Lunar_and_Planetary_Institute) |location=Houston, Texas |isbn= |page=120 |url= |oclc=40770730 }} ;Shutter ridge: A [shutter ridge](/source/shutter_ridge) is a ridge that has moved along a fault line, blocking or diverting drainage. Typically, a shutter ridge creates a valley corresponding to the alignment of the fault that produces it. === Volcanic and hydrothermal ridges === ;[Pressure ridge (lava)](/source/Pressure_ridge_(lava)): A specific case of [pressure ridge](/source/pressure_ridge), also known as a ''tumulus'', usually develops in lava flows, especially when slow-moving lava beneath a solidified crust wells upward. The brittle crust usually buckles to accommodate the inflating core of the flow, thus creating a central crack along the length of the tumulus.{{cite book |last1=Schmincke |first1=Hans-Ulrich |title=Volcanism |date=2003 |publisher=Springer |location=Berlin, Germany |isbn=9783540436508 |pages=13–20 |url= |oclc= }} ;Volcanic crater/caldera ridges: Large [volcano](/source/volcano)es often have a central [crater](/source/volcanic_crater) or [caldera](/source/caldera) or both, bordered by rims that form circular ridges. ;Volcanic subglacial ridges: [Subglacial volcanic eruptions](/source/Subglacial_volcano) can create volcanic ridges, known as ''[tindar](/source/Tindar_(landform))s'', that vary from tens of meters up to 250 meters in height. Tindars are a piles of volcanic ash that have been generated by explosive subaqueous eruptions in a glacial meltwater-filled vault or lake within a glacier or ice sheet.{{cite book | editor-last1=Elias | editor-first1=S.A. | editor-last2=Mock | editor-first2=C.J. |year=2013 |section=Quaternary Vulcanism: Subglacial Landforms |author=Smellie, J.L. |title=Encyclopedia of Quaternary Science |publisher=Elsevier |location=New York, New York |pages=780–802 |isbn=978-0-444-53643-3 | edition=2nd |url= |oclc= }} == See also == {{Commons category|Ridges}} * {{annotated link|Drumlin}} * {{annotated link|Fall line (topography)}} * {{annotated link|Hill chain}} * {{annotated link|Interlocking spur}} * {{annotated link|Mountain chain}} * {{annotated link|Mountain range}} * {{annotated link|Tectonic uplift}} == References == {{Reflist}} Category:Ridges Category:Montane ecology Category:Erosion landforms Category:Slope landforms Ridges Category:Oronyms --- Adapted from the Wikipedia article [Ridge](https://en.wikipedia.org/wiki/Ridge) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Ridge?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.