Ridge 714908 218947617 2008-06-12T21:57:19Z 85.235.223.49 {{otheruses4|the use of the term in geography and physical geology|other meanings}} [[image:Bristol tenn ridgelines2.jpg|300px|thumb|right|Stratigraphic ridge found in Northeastern [[Tennessee]]]] A '''ridge''' is a geological feature that features a continuous elevational crest for some distance. Ridges are usually termed [[hill]]s or [[mountain]]s as well, depending on size. There are several main types of ridges: *Dendritic ridge: In a typical plateau terrain, the stream drainage valleys will leave intervening ridges. These are by far the most common ridges. These ridges usually represent slightly harder rock, but not always -- they are often simply because there were larger joint spaces 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. *Stratigraphic ridge: In places such as the [[Ridge-and-valley Appalachians]], very long, very even, very straight ridges are formed due to the fact that they're the uneroded remaining edges of the more resistant strata that were folded laterally. Similar ridges have formed in places such as the [[Black Hills]], where the ridges form concentric circles around the [[igneous]] core. Sometimes these ridges are called "hogback ridges". *Oceanic spreading ridge: In [[tectonic]] spreading zones around the world, such as at the [[Mid-Atlantic Ridge]], the volcanic activity forming new plate boundary forms volcanic ridges at the spreading zone. Isostatic settling and erosion gradually reduce the elevations moving away from the zone. *Crater ridges: Large [[meteorite]] strikes typically form large [[impact crater]]s bordered by circular ridges. *Volcanic caldera ridges: Large [[volcano]]es often leave collapsed central [[caldera]]s that are bordered by circular ridges. *Thrust fault ridges: [[Thrust fault]]s often form [[escarpment]]s. Sometimes the tops of the escarpments form not plateaus, but slope back so that the edges of the escarpments form ridges. *Dune ridges: In areas of large-scale [[dune]] activity, certain types of dunes result in [[sand]] ridges. *Moraines and eskers: [[Glacier|Glacial]] activity may leave ridges in the form of [[moraine]]s and [[esker]]s. An arête is a thin ridge of rock that is formed by glaciers. *Volcanic subglacial ridges: Many [[subglacial volcano]]es create ridge-like formations when lava erupts through a thick [[glacier]] or [[ice sheet]]. ==See also== *[[Tectonic uplift]] ==External links== *[http://interridge.org InterRidge] An initiative for international cooperation in ridge-crest studies [[Category:Ridges| ]] [[cs:Hřbet (geomorfologie)]] [[de:Gebirgskamm]] [[fr:Crête]] [[nl:Bergkam]] [[ja:尾根]] [[pl:Grzbiet górski]] [[pt:Tergo]] [[ru:Кряж]] [[sr:Гребен]] [[fi:Selänne]] [[zh-yue:山脊]] [[zh:山脊]]