A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains,Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, p 87. . or a contiguous ridge of mountains within a larger

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...

. The term is also used for elongated

fold mountain Fold mountains are formed by the effects of folding on layers within the upper part of the Earth's crust. Before the development of the theory of plate tectonics and before the internal architecture of thrust belts became well understood, the te ...

s with several parallel chains ("chain mountains"). While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct Summit (topography), summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally con ...

s tends to be referred to a

ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

hill chain A hill chain, sometimes also hill ridge, is an elongated line of hills that usually includes a succession of more or less prominent hilltops, domed summits or ''kuppen'', hill ridges and saddles and which, together with its associated lateral ri ...

. Elongated mountain chains occur most frequently in the

orogeny Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

of fold mountains, (that are folded by lateral pressure), and

nappe In geology, a nappe or thrust sheet is a large sheetlike body of rock (geology), rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision z ...

belts (where a sheetlike body of rock has been pushed over another rock mass). Other types of range such as horst ranges,

fault block Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust. Large areas of bedrock are broken up into blocks by faults. Blocks are characterized by rela ...

mountain or truncated uplands rarely form parallel mountain chains. However, if a truncated upland is eroded into a high

table land A table or tableland is a butte, flank of a mountain, or mountain, that has a flat top. This kind of landform has numerous names, including: * Butte * Mesa * * Potrero * Tepui * Terrace * Tuya A tuya is a flat-topped, steep-sided vo ...

, the incision of valleys can lead to the formations of mountain or hill chains.

Formation of parallel mountain chains

The chain-like arrangement of summits and the formation of long, jagged

mountain crest A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

s – known in Spanish as sierras ("saws") – is a consequence of their collective formation by mountain building forces. The often linear structure is linked to the direction of these thrust forces and the resulting mountain folding which in turn relates to the

fault line In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

s in the upper part of the

earth's crust Earth's crust is Earth's thin outer shell of rock, referring to less than 1% of Earth's radius and volume. It is the top component of the lithosphere, a division of Earth's layers that includes the crust and the upper part of the mantle. The ...

, that run between the individual mountain chains. In these

fault zone In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

s, the rock, which has sometimes been pulverised, is easily eroded, so that large

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

valleys are carved out. These, so called

longitudinal valley A longitudinal valley is an elongated valley found between two almost-parallel mountain chains in geologically young fold mountains, such as the Alps, Carpathians, Andes, or the highlands of Central Asia. They are often occupied and shaped by a ...

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. g. the

Cordilleras A cordillera is an extensive chain and/or network system of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly us ...

) to produce roughly parallel chains is due to their rock structure and the propulsive forces of

plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...

. The uplifted rock masses are either magmatic

plutonic rock Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March ...

s, easily shaped because of their higher temperature, or

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

s or

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...

s, which have a less robust structure, that are deposited in the

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

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 A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If ...

folds of a

belt (e.g. the

Central Alps The Alps form a large mountain range dominating Central Europe, including parts of Italy, France, Switzerland, Liechtenstein, Austria, Slovenia, Germany and possibly Hungary (if one includes the Kőszeg Mountains). This article describes the del ...

) 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 An arête ( ) is a narrow ridge of rock which separates two valleys. It is typically formed when two glaciers erode parallel U-shaped valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequen ...

s or ridges that follow the

strike Strike may refer to: People * Strike (surname) Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm *Airstrike, military strike by air forces on either a suspected ...

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 A transverse valley is a valley which cuts at right angles across a ridgeWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 548. . or, in mountainous terrain a valley that generally runs at right angles to the li ...

s, which often form

water gap A water gap is a gap that flowing water has carved through a mountain range or mountain ridge and that still carries water today. Such gaps that no longer carry water currents are called wind gaps. Water gaps and wind gaps often offer a prac ...

s. During the course of earth history,

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

by water, ice and wind carried away the highest points of the mountain crests and carved out individual summits or summit chains. Between them, notches were formed that, depending on

altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...

and rock-type, form knife-edged cols or gentler

mountain pass A mountain pass is a navigable route through a mountain range or over a ridge. Since many of the world's mountain ranges have presented formidable barriers to travel, passes have played a key role in trade, war, and both Human migration, human a ...

es and saddles.

Dominant rocks and mountain forms

Nappe or fold mountains, with their roughly parallel mountain chains, generally have a common

geological Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Eart ...

age, but may consist of various types of

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

. For example, in the Central Alps,

granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quart ...

rocks,

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

es and metamorphic

slate Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. ...

are found, while to the north and south, are the

Limestone Alps The Limestone Alps (german: Kalkalpen) are a mountain ranges system of the Alps in Central Europe. They are of economic importance, including as a watershed source of drinking water. They have many accessible dripstone and ice caves. Geography T ...

. The

Northern Limestone Alps The Northern Limestone Alps (german: Nördliche Kalkalpen), also called the Northern Calcareous Alps, are the ranges of the Eastern Alps north of the Central Eastern Alps located in Austria and the adjacent Bavarian lands of southeastern Germany. ...

are, in turn, followed by soft

flysch Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building ep ...

mountains and the

molasse __NOTOC__ The term "molasse" () refers to sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flys ...

zone. The type of rock influences the appearance of the mountain ranges very markedly, because

leads to very different topography depending on the

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of the rock and its

petrological Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...

structure. In addition to height and climate, other factors are the

layering Layering has evolved as a common means of vegetative propagation of numerous species in natural environments. Layering is also utilized by horticulturists to propagate desirable plants. Natural layering typically occurs when a branch touches ...

of the rock, its

gradient In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gradi ...

and

aspect Aspect or Aspects may refer to: Entertainment * ''Aspect magazine'', a biannual DVD magazine showcasing new media art * Aspect Co., a Japanese video game company * Aspects (band), a hip hop group from Bristol, England * ''Aspects'' (Benny Carter ...

, the types of

waterbody A body of water or waterbody (often spelled water body) is any significant accumulation of water on the surface of Earth or another planet. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as p ...

and the lines of

dislocation In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to sl ...

. For hard rock massifs, rugged rock faces (e.g. in the

Dolomites The Dolomites ( it, Dolomiti ; Ladin: ''Dolomites''; german: Dolomiten ; vec, Dołomiti : fur, Dolomitis), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range located in northeastern Italy. They form par ...

) and mighty

scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically ha ...

slopes are typical. By contrast, flysch or slate forms gentler mountain shapes and ''

kuppen A ''Kuppe'' is the term used in German-speaking central Europe for a mountain or hill with a rounded summit that has no rock formation, such as a tor, on it. A range of such hills is called a ''Kuppengebirge''. In geology the term also refers ...

'' or domed mountaintops, because the rock is not porous, but easily shaped.

References

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. 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 *
Gebirge
', in: Lueger, Otto: ''Lexikon der gesamten Technik und ihrer Hilfswissenschaften'', Vol. 4 Stuttgart, Leipzig, 1906, pp
316317
{{Authority control Landforms ! !

Formation of parallel mountain chains

Dominant rocks and mountain forms

See also

References

Literature