Editing Mountain chain

{{Short description|Row of high mountain summits}}
[[File:Zell-Pfarre Peiner Kobla 01.jpg|thumb|upright=1.2|The [[Karawanks]], a single, long mountain chain. This is the [[Koschuta]] ridge near Zell, [[Carinthia]]]]
A '''mountain chain''' is a row of high [[mountain summit]]s, a linear sequence of interconnected or related mountains,<ref>Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, p 87. {{ISBN|0-14-051094-X}}.</ref> or a contiguous ridge of mountains within a larger [[mountain range]]. The term is also used for elongated [[fold mountain]]s with several parallel chains ("chain mountains").

While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of [[hill]]s tends to be referred to a [[ridge]] or [[hill chain]].

Elongated mountain chains occur most frequently in the [[orogeny]] of fold mountains, (that are folded by lateral pressure), and [[nappe]] belts (where a sheetlike body of rock has been pushed over another rock mass). Other types of range such as [[horst (geology)|horst ranges]], [[fault block]] mountain or [[truncated upland]]s rarely form parallel mountain chains. However, if a truncated upland is eroded into a high [[table land]], the incision of valleys can lead to the formations of mountain or hill chains.

== Formation of parallel mountain chains ==
[[File:Satellitenaufnahme der Alpen.jpg|thumb|upright=1.2|In this satellite image of the [[Alps]], the snow limit picks out the individual mountain chains]]
[[File:Централен Балкан.jpg|thumb|260px|A view of the [[Balkan Mountains]] chain]]

The chain-like arrangement of summits and the formation of long, jagged [[mountain crest]]s – known in Spanish as [[wikt:sierra#Spanish|sierras]] ("saws") – is a consequence of their collective formation by [[orogeny|mountain building forces]]. The often linear structure is linked to the direction of these thrust forces and the resulting [[folding (geology)|mountain folding]] which in turn relates to the [[fault line]]s in the upper part of the [[Earth's crust]], that run between the individual mountain chains. In these [[fault zone]]s, the rock, which has sometimes been pulverised, is easily eroded, so that large [[river]] valleys are carved out. These, so called [[longitudinal valley]]s reinforce the trend, during the early mountain building phase, towards the formation of parallel chains of mountains.

The tendency, especially of fold mountains (e.&nbsp;g. the [[Cordilleras]]) to produce roughly parallel chains is due to their rock structure and the propulsive forces of [[plate tectonics]]. The uplifted rock masses are either magmatic [[plutonic rock]]s, easily shaped because of their higher temperature, or [[sediment]]s or [[metamorphic rock]]s, which have a less robust structure, that are deposited in the [[syncline]]s. As a result of orogenic movements, strata of folded rock are formed that are crumpled out of their original horizontal plane and thrust against one another. The longitudinal stretching of the folds takes place at right angles to the direction of the lateral thrusting. The [[overthrust]] folds of a [[nappe]] belt (e.g. the [[Central Alps]]) are formed in a similar way.

Although the fold mountains, chain mountains and nappe belts around the world were formed at different times in the Earth's history, all during their initial mountain building phases, they are nevertheless morphologically similar. Harder rock forms continuous [[arête]]s or ridges that follow the [[strike (geology)|strike]] of the beds and folds. The mountain chains or ridges therefore run approximately parallel to one another. They are only interrupted by short, usually narrow, [[transverse valley]]s, which often form [[water gap]]s. During the course of Earth history, [[erosion (geology)|erosion]] by water, ice and wind carried away the highest points of the mountain crests and carved out individual summits or [[double summit|summit chains]]. Between them, notches were formed that, depending on [[altitudinal zonation|altitude]] and rock-type, form knife-edged [[col]]s or gentler [[mountain pass]]es and [[saddle (geology)|saddles]].

== Dominant rocks and mountain forms ==
[[File:Vedauwoo Rocks in winter.jpg|thumb|upright=1.2|The remains of an old mountain chain in the [[Laramie Mountains]], Colorado]]
Nappe or fold mountains, with their roughly parallel mountain chains, generally have a common [[geological]] age, but may consist of various types of [[Rock (geology)|rock]]. For example, in the Central Alps, [[granite|granitic]] rocks, [[gneiss]]es and metamorphic [[slate]] are found, while to the north and south, are the [[Limestone Alps]]. The [[Northern Limestone Alps]] are, in turn, followed by soft [[flysch]] mountains and the [[molasse]] zone. <!--see Disk. Many mountain chains also have rocks that were deposited later e.g. [[limestone]] from [[coral reef]]s - such as in the [[Dachstein massif]], the [[Leitha Mountains]] or the [[Westerwald]].-->

The type of rock influences the appearance of the mountain ranges very markedly, because [[erosion (geology)|erosion]] leads to very different topography depending on the [[hardness]] of the rock and its [[petrological]] structure. In addition to height and climate, other factors are the [[strata|layering]] of the rock, its [[gradient]] and [[aspect (geography)|aspect]], the types of [[waterbody]] and the lines of [[dislocation]]. For hard rock massifs, rugged rock faces (e.g. in the [[Dolomites]]) and mighty [[scree]] slopes are typical. By contrast, flysch or slate forms gentler mountain shapes and ''[[kuppen]]'' or domed mountaintops, because the rock is not porous, but easily shaped.

== See also ==
* [[Orogeny]]
* [[Tectonics]]
* [[List of highest mountains on Earth]]
* [[List of mountain ranges]]

== References ==
{{Reflist}}

== Literature ==
* ''Wissen heute: Geologie''. Kaiser-Verlag, Florence/Klagenfurt, 1995
* ''Der geologische Aufbau Österreichs''. Geologische Bundesanstalt, Springer-Verlag Vienna/ New York
* PanGeo, ''Erdwissenschaften in Österreich''. Conference proceedings, 200 pp., Sessions on the Neogene, TRANSALP I and II. Univ. Salzburg, 2005
* ''Fischer-Lexikon Geographie'', pp.&nbsp;101–129, Frankfurt, 1959
* ''Großer Weltatlas, Enzyklopädischer Teil'' (mountain building, folds and faults, the rock cycle). Publ. ÖAMTC, Vienna, ~1980
* André Cailleux: ''Der unbekannte Planet: Anatomie der Erde''. Kindlers Universitätsbibliothek, Munich, 1968, Chapters 1 and 3
* ''[http://www.zeno.org/Lueger-1904/A/Gebirge Gebirge]'', in: Lueger, Otto: ''Lexikon der gesamten Technik und ihrer Hilfswissenschaften'', Vol. 4 Stuttgart, Leipzig, 1906, pp. [http://www.zeno.org/Lueger-1904/K/lueger-1904-041-0316 316]-[http://www.zeno.org/Lueger-1904/K/lueger-1904-041-0317 317].

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[[Category:Landforms]]
[[Category:Mountains|!]]
[[Category:Mountain ranges|!]]