Home  ›  Mountain

Mountain

Highest mountain: K2 , Karakoram to the Sino-Pakistan second behind the top of Everest
Mountain landscape in the foreground and Augstmatthorn (2137 m) in the background (canton of Bern, Switzerland)

A mountain is a form topographic to highlight positive on the surface of terrestrial planets (like Mars or satellites like the Moon ) and being part of a package - a mountain - or forming an isolated terrain. The name "mountain" is a term generally used as a place name (sometimes even in volumes close to those of a hill), as energetic relief (defined by the altitude and energy, and we reserve the terms of hill or of plateau landforms at lower energy and other development) or as a structured form by tectonics. There is indeed a great variety of geological structures called "mountain" in a common language (folding, volcanoes active or extinct, seamounts, etc.).. To define a mountainous terrain, according to his energy and age, people commonly speak, respectively small, medium and high mountains or mountain young or old.

Terms such as top , peak , Mount , hand , etc.. are used as synonyms.

The highest mountain known to the solar system is Olympus Mons , shield volcano on the planet in March , with an elevation of 27 km. On Earth , the highest mountain is the Mount Everest with 8,848 meters if we consider the difference between the top and the level of the sea or the volcano Mauna Kea to 10,230 meters with reference to the difference between his Summit and its submarine base, or the Chimborazo considering the distance from the center of the Earth.

Summary

Characteristics and Training

The altitude of a mountain land is the height of its peak relative to sea level. The importance of a mountain can also be measured by the difference in altitude between the summit and surrounding lands.

The mountainous terrain covers 54% of Asia , 36% of North America , 26% of Europe , 22% of South America , 17% of Australia , and 3% of Africa. In all, 24% of continental landscapes are mountainous. 10% of humanity lives in mountainous regions. Most rivers in the world are fed by mountain springs, and over half of humanity depends on this water .

A mountain is formed of a summit, but also a base and a root due to the folding of geological strata: this database and this root are more impressive than the top, the depth of the root can be estimated by the anomaly Gravitational it generates (up to several tens of kilometers deep).

A mountain is always formed due to forces that affect the balance gravity ( geoid , or fields of equal weight) moving (or adding) rocks upwards. The resulting imbalance causes a positive relief, and isostatic compensation (the flotation crust on the mantle ) thickening of the crust (which can pass from a usual thickness of 30 km over 60 km). Two main mechanisms used to find a steady state (no relief):

  • expansion observed in the Alps , the Basin and Range of the western United States , in the Andes , in Tibet , in the Hercynian belt ...
  • the erosion - sedimentation : uprooting of rock material by mechanical action ( freeze , unlike thermal action of glaciers, wind, etc.) or by chemical weathering (dissolution of inorganic compounds in water as in karst landscapes ) and then transporting those it by simple gravitational action (falling rocks), glacial ( moraine ) or river ( thrust ).

Both mechanisms cause crustal thinning, and generally cause a decrease in relief (absolute and relative).

There are other mechanisms like the mountains are volcanoes (explosion from the summit like that of Mount St. Helens in 1980 ), magmatic processes, earthquakes of high magnitude that can redefine the landscape.

Orogeny

Main articles: orogeny and continental collision.

The orogeny (literally "birth of relief") may have several causes but the principal is due to movements tectonic. The subduction of an oceanic plate under a continental or oceanic plate forms a mountain range (the Andes , the Rocky Mountains ). The collision of two continental plates can track and create a chain of collisions (the Alps , the Caucasus , the Himalayas ). The crust is thickened by faults and folds speaking at all scales (from the continental scale to the microscopic scale).

The presence of a thermal anomaly may also cause the formation of a relief through the provision of equipment ( volcano ) and / or by changing the density (and hence buoyancy) of the crust or lithosphere (warmer / less dense). The continental crust is lighter than the mantle lithosphere underlying most of the crustal thickening is absorbed at the interface crust / mantle (the Moho is deeper). This thickening causes an increase in relief and usually a local increase erosion. Erosion can also be responsible for creating embossed isostatic response.

A mountain range can also be created on a border of transforming plate ( slip ) or extensively (along rift , the terrain is created by thermal effect)

Morphology of the mountains

Main article: List of mountain types.
The Matterhorn ( Cervin ), emblematic peak in Switzerland (4478 m)

The morphology of a mountain depends on various factors:

  • strain rate (vertical and horizontal movements of rocks) - tectonics;
  • the nature of the rock (soft rock reliefs give softer than the hard rock) - lithology;
  • climate, and especially the intensity, nature and distribution of precipitation, such as the presence or absence of ice.

A tectonically active mountain usually has steep slopes and sharp shapes, while a mountain inactive generally has milder forms. This classification is simplistic, however, more relevant.

The highest mountain on Earth is Mount Everest in the Himalayas (8,848 meters above sea level), or the volcano Mauna Kea in Hawaii that emerges from 4,206 meters above sea with base 5500 meters below sea level (almost 10 000 m of relief). The highest mountain in Europe is Mount Elbrus in the Caucasus (the Mont Blanc is the highest peak in Western Europe). The highest mountain known to date in the solar system is the Olympus Mons on March , volcano 26 km high with a diameter of 600 km.

Some famous mountains: the K2 , the Annapurna , the Matterhorn , Ben Nevis , the Kilimanjaro , the Mount McKinley , Mount Rose , Mount Whitney.

Erosion in the mountains

Simplified sketch of a glacial landscape in mountains

Across a mountain range, erosion is a powerful agent for mass distribution, in particular, the isostatic response to erosion causes a vertical movement up the rocks, and possibly an uprising of vertices ( if the ratio between the erosion of the peaks and valleys of erosion permits ).

  • The action of snow and frost occurs on the high slopes.
  • The action of glaciers: A glacial valley is a valley that was carved by a glacier. Under the effect of its own weight, sliding glacier moves (up to a meter per day for the Bossons glacier ) and use the rock. The field of plasticity of ice is particularly wide, the mass of ice from a glacier flows slowly by gravity. She brings with it moraines front or side. The origin of the moraines is debate among scholars: the ultraglacialistes feel they are produced by erosion of the glacier. The antiglacialistes think they are only carried by the glacier . After the withdrawal of the glacier, there are only some of the beads coated with the forest.
Click on a thumbnail to enlarge

With the end of the last ice age glaciers retreated and have shaped glacial valleys (valley or "U").
The gel is able to cut blocks into cracks in the rock. Appalachia gave their name to a type of relief, appalachian , which means the remains of an ancient mountain high leveled. Long corridors run parallel to straight backs. The gorges Appalachian form narrow passages through the links of the mountain.
The streams carry and produce blocks, pebbles, gravel (size between 4 mm and 4 cm) of sand or coarse, fine sands.

Landforms in the mountains:

History of study of mountain

The first recorded exploration of the mountain (the Greek Herodotus or Anaximander or Italian Petrarch ) are made of scholars motivated by the desire for knowledge and self .

The medieval geographies (such as Arab Christian authors, like the geographer Ibn Hawqal ) designs the mountains as the work of God who wanted to get the Earth a "frame." Avicenna gives two geological causes to the mountains, earthquakes that raise soil and to a lesser extent the erosion that leaves intact the harshest relief . Restoro Arezzo also emits a theory about the origin of mountains: it is a form of attraction from the star .

For the authors of the Renaissance , the mountains are either the result of erosion ( Leonardo da Vinci , Agricola , Palissy ) or reliefs which are in existence for the creation of the Earth .

The natural history of seventeenth and eighteenth century ushered in the scientific approach: various authors' theories of the Earth "write about it. The naturalist Jean-Louis Giraud-Soulavie described in 1780 the mountain climate in the Natural History of Southern France, Philippe Buache Mapping mountains from around the world test of physical geography in 1752. Alexander von Humboldt provides the major contribution: Young love with the mountains he climbed several peaks outstanding (including Chimborazo ). It determines including "tables of heights' for plant associations and causalities than previous linear naturalists to the mountain environments that are not seeking to study in its regional specificity, but according to the principles of general geography .

The geography Vidalian nineteenth century focused studies on interactions between people and natural environments.

Geographers of the twentieth century, as the authors of the Treaties of general physical geography (Martoni, 1909, Pech and Herve Pierre Regnault, 1994) and geographers of the French School ( Jules Blache , 1933; Deffontaines Pierre , 1947) consider Now the mountain like a combination of processes and factors that become the objects of the same scientific research.

The mountain has been a research topic that involves the international scientific community. The International Biological Program (en) of the 1970 deals with the modeling of natural processes and the Man and Biosphere entitled "Study of the impact of human activities on mountain" mobilized experts from geographical areas very different to attempt a comparative analysis of mountaineers. In the 1990s, thanks to the Rio Conference and the Agenda 21 , the mountain has been identified as a fragile ecosystem, becomes the object of attention of the international scientific community, NGOs and institutions . Moreover, many scientists are calling to start a "montologie" , .

Mountain Ranges (not exhaustive)

System Tethyan

The mountains of this system are from the closure, from the Cretaceous , ocean, Tethys , mostly by colliding plates African and Indian with Eurasia since the Eocene.

Alpine Channels

The opening of different ocean basins in the Mediterranean ( Ligurian Sea between Corsica and Provence ; Tyrrhenian Sea between Corsica , Sicily , Sardinia and Italy ; Alboran Sea between Spain and Morocco ; Aegean Sea between Greece and Turkey , etc..) complicates geology and geographical distribution of these channels.

Chain of the Pyrenees

The Pyrenees are a mountain range between the Mediterranean Sea ( Cap de Creus ) and the Atlantic Ocean ( Gulf of Biscay ), separating France and Spain and home to the Principality of Andorra. The main exception to this rule is formed by the Val d'Aran , which depends on Spain but lies on the northern slopes of the massif and the Spanish enclave village Llvia located in the Pyrenees-Orientales near Bourg Lady in Cerdanya. By orography, including anomalies, the fall is included Cerdanya located on the south side of the chain (The Segre and Carol), but shared between France and Spain as the Garonne from the glacier Aneto in Aragon and springs in Val d'Aran.

The Pyrenees crosses 6 French departments east to west are: Eastern Pyrenees , the Aude , the Arige , the Haute-Garonne , the Hautes-Pyrenees and Pyrenees-Atlantiques , which are part of three regions Aquitaine , Midi-Pyrenees , Languedoc-Roussillon. It crosses the Spanish autonomous communities of Catalonia , of Aragon , of Navarre and Euskadi (Basque Country in Spain).

Channels Middle East

Channels peri-Himalayan

System of the American Cordillera

American Cordillera is the result of subduction since the Cretaceous of the Pacific plate beneath the North American Plate (Rocky Mountains and coastal ranges of the Pacific, the Alaska to Mexico ) and South America ( Andes , the Equator in the South of Chile ).

Rocky Mountains

The Rockies stretch from Canada to the United States of America.

Channels Pacific coastal

The Pacific coastal ranges extend from the Alaska to Mexico

Andes

The Andes spans several countries in South America : Chile , Peru , Ecuador , Argentina , Colombia , Bolivia and Venezuela.

Other systems peri-Pacific

System Hercynian

Flora and fauna
Main article: Tiering.
This section is empty, insufficiently detailed or incomplete. Your help is welcome!

Economy mountain

The mountain is the site of numerous primary sector economic activities and livelihoods as the pastoral transhumance of bringing sheep , cattle , goats , llamas , alpacas , vicuna or yak to pastures during the summer pastures for the production of cheese , of milk , for meat and wool (as the famous cashmere ). Pastoralism is generally established in the alpine zone , where biotopes as the alpine grass , the puna or pramo. Livestock in the mountains stood in these stages due to an environment too dry , too cold, too little sun or too steep to make agriculture possible or profitable.

However mountain cultures have also an important traditional agriculture, centered on the potato , the barley and buckwheat can be grown at altitudes up to 4 000 to 4 500 m . Some plants originating in tropical climates such as rice , the coffee or tea for their part of the cultures located in areas of medium altitude (up to about 2000 m).

Mountain environments are also known to be an area of exploitation of timber and mineral deposits , such as the iron in the Belledonne in the Dauphin , to the middle of last century.

Mountaineering

Winter

Summer

oronyms

Main article: oronyms.

In onomastics , a oronyms is name of a mountain. However oronyms are sometimes used for simple heights.

Mountains in the Solar System

The Earth is not the only star to have the mountains because it is part of the family of stars like LBS, who have a hard crust, and therefore can have mountain ranges. These are the terrestrial planets ( Venus , March ), and satellites as the Moon or Io. The highest mountain known to the solar system is Olympus Mons , shield volcano in March , with an elevation of 26 km.

References

  1. (en) International Year of Freshwater 2003 . Retrieved on 2006-12-07.
  2. (en) The Mountain Institute . Retrieved on 2006-12-07.
  3. Molnar , P., and England , P., 1990, Late Cenozoic uplift of mountain ranges and global climate change: Chicken or egg?: Nature, v. 346, p. 29-34, doi: 10.1038/346029a0.
  4. John Riser, erosion and natural landscapes, page 33
  5. Bernard Debarbieux The makers of mountain and imaginary political territoriality: XVIII - XXI century, CNRS, June 24, 2010, 374 p. ( ISBN 978-2-271-06985-6 )
  6. Andr Miquel, Human geography of the Muslim world until the mid 11th century, EHESS, 1980.
  7. Gohau Gabriel, A History of Geology, 1990, Editions du Seuil, p. 32
  8. History of Science, collective, headed by Rene Taton , PUF, 4 volumes, 1995, p.111
  9. Numa Broc, The mountains seen by geographers and naturalists of the French language in the eighteenth century, CTHS, 1969.
  10. Martin Price, Global change in the Mountains, Parthenon Publishing, 1999.
  11. Veyret Yvette (ed.), Mountains: address and geographical issues, SEDES, 2001
  12. Bruno Messerli and Jack Ives, Mountains of the world: a global priority, Parthenon, 1997
  13. Fausto Sarmiento, The challenges of mountain research in terminology and knowledge, Revue de Gographie Alpine, Grenoble, No. 2, 2001, pp 73-77
  14. Sacareau Isabelle, The mountain: a geographical approach, Belin Sup, 2003, p.123
  15. Isabelle Sacareau, op. cit., p.119

Bibliography

  • Henri Rougier, Gabriel Wackermann, Grard Mottet, Mountain Geography, ed. Ellipses, Paris, 2001, ( ISBN 2729808051 )
  • Yvette Veyret (ed.), Mountains: address and geographical issues, ed. SEDES, Paris, 2001
  • Atlas of the most beautiful mountain Glant, Grenoble, 2007, ( ISBN 9782723461191 )
  • E. Bordessoule Mountains, Editions du Temps
  • Isabelle Sacareau, The mountain: a geographical approach, ed. Belin Sup, Paris, 2003
  • B. Messerli JDIves, The mountains in the world, Ed Glnat, 1999
  • G. Wackermann Mountains and mountain cultures, ed. Ellipses, Paris, 2001

See also

The Earth : internal structure Hydrosphere Relief Atmosphere
Hill Dune mountains Beach Plain Plateau


Leave a Reply


Frequently Asked Questions

1 vote, average: 4.00 out of 51 vote, average: 4.00 out of 51 vote, average: 4.00 out of 51 vote, average: 4.00 out of 51 vote, average: 4.00 out of 5 (1 votes, average: 4.00 out of 5, rated)
Loading ... Loading ...
Help us improve the wiki Send Your Comments