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Geography of the Alps

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93-469: The Alps form a large mountain range dominating Central Europe , including parts of Italy , France , Switzerland , Liechtenstein , Austria , Slovenia , Germany and Hungary . This article describes the delimitation of the Alps as a whole and of subdivisions of the range, follows the course of the main chain of the Alps and discusses the lakes and glaciers found in the region. In some areas, such as

186-611: A crescent shaped geographic feature of central Europe that ranges in an 800 km (500 mi) arc (curved line) from east to west and is 200 km (120 mi) in width. The mean height of the mountain peaks is 2.5 km (1.6 mi). The range stretches from the Mediterranean Sea north above the Po basin, extending through France from Grenoble , and stretching eastward through mid and southern Switzerland. The range continues onward toward Vienna , Austria, and southeast to

279-506: A delamination of the orogenic root beneath them. Mount Rundle on the Trans-Canada Highway between Banff and Canmore provides a classic example of a mountain cut in dipping-layered rocks. Millions of years ago a collision caused an orogeny, forcing horizontal layers of an ancient ocean crust to be thrust up at an angle of 50–60°. That left Rundle with one sweeping, tree-lined smooth face, and one sharp, steep face where

372-743: A major commercial and military road between Western Europe and Italy. The pass was crossed by many troops on their way to the Italian peninsula. From Constantine I , Pepin the Short and Charlemagne to Henry IV , Napoléon and more recently the German Gebirgsjägers during World War II . Now the pass has been supplanted by the Fréjus Highway Tunnel (opened 1980) and Rail Tunnel (opened 1871). The Saint Gotthard Pass crosses from Central Switzerland to Ticino ; in 1882

465-589: A major continent-continent collision, is called an accretionary orogen. The North American Cordillera and the Lachlan Orogen of southeast Australia are examples of accretionary orogens. The orogeny may culminate with continental crust from the opposite side of the subducting oceanic plate arriving at the subduction zone. This ends subduction and transforms the accretional orogen into a Himalayan -type collisional orogen. The collisional orogeny may produce extremely high mountains, as has been taking place in

558-657: A man was in 1788; the first ascent by a woman was in 1808. By the mid-1850s Swiss mountaineers had ascended most of the peaks and were eagerly sought as mountain guides. Edward Whymper reached the top of the Matterhorn in 1865 (after seven attempts), and in 1938 the last of the six great north faces of the Alps was climbed with the first ascent of the Eiger Nordwand (north face of the Eiger). Important geological concepts were established as naturalists began studying

651-412: A noncollisional orogenic belt, and such belts are sometimes called Andean-type orogens . As subduction continues, island arcs , continental fragments , and oceanic material may gradually accrete onto the continental margin. This is one of the main mechanisms by which continents have grown. An orogen built of crustal fragments ( terranes ) accreted over a long period of time, without any indication of

744-525: A permanent laboratory exists inside a glacier under the Jungfraujoch , devoted exclusively to the study of Alpine glaciers. Orogeny Orogeny ( / ɒ ˈ r ɒ dʒ ə n i / ) is a mountain - building process 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 to form one or more mountain ranges . This involves

837-442: A pronounced linear structure resulting in terranes or blocks of deformed rocks, separated generally by suture zones or dipping thrust faults . These thrust faults carry relatively thin slices of rock (which are called nappes or thrust sheets, and differ from tectonic plates ) from the core of the shortening orogen out toward the margins, and are intimately associated with folds and the development of metamorphism . Before

930-469: A series of geological processes collectively called orogenesis . These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism . Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere ( crust and uppermost mantle ). A synorogenic (or synkinematic ) process or event

1023-604: A tunnel 1.6 km (1 mi) long was built along the route of the pass in the mid-19th century. With a summit of 2,469 m (8,100 ft), the Great St Bernard Pass is one of the highest in the Alps, crossing the Italian-Swiss border east of the Pennine Alps along the flanks of Mont Blanc. The pass was used by Napoleon Bonaparte to cross 40,000 troops in 1800. The Mont Cenis pass has been

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1116-646: Is sedimentary rock formed during mountain building. The Alpine orogeny occurred in ongoing cycles through to the Paleogene causing differences in folded structures, with a late-stage orogeny causing the development of the Jura Mountains . A series of tectonic events in the Triassic, Jurassic and Cretaceous periods caused different paleogeographic regions. The Alps are subdivided by different lithology (rock composition) and nappe structures according to

1209-446: Is initiated along one or both of the continental margins of the ocean basin, producing a volcanic arc and possibly an Andean-type orogen along that continental margin. This produces deformation of the continental margins and possibly crustal thickening and mountain building. Mountain formation in orogens is largely a result of crustal thickening. The compressive forces produced by plate convergence result in pervasive deformation of

1302-547: Is not possible to define the Alps geologically, since the same orogenous events that created the Alps also created neighbouring ranges such as the Carpathians (see also geology of the Alps ). The Alps are a distinct physiographic province of the larger Alpine System physiographic division, but the Alps are composed of three distinct physiographic sections, the Eastern, Western and Southern Alps. While smaller groups within

1395-503: Is of continental European origin, above which are stacked marine sediment nappes, topped off by nappes derived from the African plate. The Matterhorn is an example of the ongoing orogeny and shows evidence of great folding. The tip of the mountain consists of gneisses from the African plate; the base of the peak, below the glaciated area, consists of European basement rock. The sequence of Tethyan marine sediments and their oceanic basement

1488-458: Is one that occurs during an orogeny. The word orogeny comes from Ancient Greek ὄρος ( óros )  'mountain' and γένεσις ( génesis )  'creation, origin'. Although it was used before him, the American geologist G. K. Gilbert used the term in 1890 to mean the process of mountain-building, as distinguished from epeirogeny . Orogeny takes place on

1581-624: Is sandwiched between rock derived from the African and European plates. The core regions of the Alpine orogenic belt have been folded and fractured in such a manner that erosion produced the characteristic steep vertical peaks of the Swiss Alps that rise seemingly straight out of the foreland areas. Peaks such as Mont Blanc, the Matterhorn, and high peaks in the Pennine Alps, the Briançonnais, and Hohe Tauern consist of layers of rock from

1674-422: Is still in use today, though commonly investigated by geochronology using radiometric dating. Based on available observations from the metamorphic differences in orogenic belts of Europe and North America, H. J. Zwart (1967) proposed three types of orogens in relationship to tectonic setting and style: Cordillerotype, Alpinotype, and Hercynotype. His proposal was revised by W. S. Pitcher in 1979 in terms of

1767-491: Is still taking place, are characterized by frequent volcanic activity and earthquakes . Older orogenic belts are typically deeply eroded to expose displaced and deformed strata . These are often highly metamorphosed and include vast bodies of intrusive igneous rock called batholiths . Subduction zones consume oceanic crust , thicken lithosphere, and produce earthquakes and volcanoes. Not all subduction zones produce orogenic belts; mountain building takes place only when

1860-480: Is taking place today in the Southern Alps of New Zealand). Orogens have a characteristic structure, though this shows considerable variation. A foreland basin forms ahead of the orogen due mainly to loading and resulting flexure of the lithosphere by the developing mountain belt. A typical foreland basin is subdivided into a wedge-top basin above the active orogenic wedge, the foredeep immediately beyond

1953-783: Is the Periadriatic Seam . The Northern Limestone Alps are separated from the Central Eastern Alps by the Grauwacken Zone . However, the geologic subdivision, based on tectonics , suggests a different system: The Western Alps are commonly subdivided into the following: Within the Eastern Alps, the most widely used subdivision is the Alpine Club's 1984 classification , which divides the region into about seventy small areas. The "main chain of

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2046-604: Is usually taken to be the Colle di Cadibona , at 435 m above sea level, above Savona on the Italian coast. The Rhône forms a clear boundary between the tectonically -formed Alps and the largely volcanically -formed Massif Central. Moving upstream, the Rhône turns to the east near Lyon , and passes to the south of the Jura range before reaching Lake Geneva . An area of flat ground reaches from there to Lake Neuchâtel , continuing

2139-534: The Adriatic Sea and Slovenia . To the south it dips into northern Italy and to the north extends to the southern border of Bavaria in Germany. In areas like Chiasso , Switzerland, and Allgäu , Bavaria, the demarcation between the mountain range and the flatlands are clear; in other places such as Geneva , the demarcation is less clear. The Alps are found in the following countries: Austria (28.7% of

2232-453: The Alpine type orogenic belt , typified by a flysch and molasse geometry to the sediments; ophiolite sequences, tholeiitic basalts, and a nappe style fold structure. In terms of recognising orogeny as an event , Leopold von Buch (1855) recognised that orogenies could be placed in time by bracketing between the youngest deformed rock and the oldest undeformed rock, a principle which

2325-864: The Colle della Maddalena , to the north. Upon reaching the Swiss border, the line of the main chain heads approximately east-northeast, a heading it follows until its end near Vienna. The northeast end of the Alpine arc, directly on the Danube , which flows into the Black Sea, is the Leopoldsberg near Vienna. In contrast, the southeastern part of the Alps ends on the Adriatic Sea in the area around Trieste towards Duino and Barcola . The Alps have been crossed for war and commerce, and by pilgrims, students and tourists. Crossing routes by road, train, or foot are known as passes , and usually consist of depressions in

2418-511: The Gotthard Base Tunnel , was opened, which connects Erstfeld in canton of Uri with Bodio in canton of Ticino by two single tubes of 57.1 km (35.5 mi). It is the first tunnel that traverses the Alps on a flat route. From 11 December 2016, it has been part of the regular railway timetable and used hourly as standard ride between Basel / Lucerne / Zürich and Bellinzona / Lugano / Milan . The highest pass in

2511-640: The Himalayas for the last 65 million years. The processes of orogeny can take tens of millions of years and build mountains from what were once sedimentary basins . Activity along an orogenic belt can be extremely long-lived. For example, much of the basement underlying the United States belongs to the Transcontinental Proterozoic Provinces, which accreted to Laurentia (the ancient heart of North America) over

2604-588: The Julian Alps (the last being shared with Italy). The town of Idrija may be taken as marking the dividing line between the Alps to the north and the karst plateau to the south, which then leads on to the mountains of the Balkan Peninsula. The remainder of the southern edge of the Alps is clearly delimited by the basin of the Po . This delimitation of the Alps is, however, largely subjective and open to argument. In particular, some people restrict

2697-607: The Oxford English Dictionary , the Latin Alpes might derive from a pre-Indo-European word * alb "hill"; "Albania" is a related derivation. Albania, a name not native to the region known as the country of Albania , has been used as a name for several mountainous areas across Europe. In Roman times , "Albania" was a name for the eastern Caucasus , while in the English languages "Albania" (or "Albany")

2790-708: The Pangaean supercontinent consisted of a single tectonic plate ; it broke into separate plates during the Mesozoic Era and the Tethys sea developed between Laurasia and Gondwana during the Jurassic Period. The Tethys was later squeezed between colliding plates causing the formation of mountain ranges called the Alpide belt , from Gibraltar through the Himalayas to Indonesia —a process that began at

2883-466: The Romanticists , followed by the golden age of alpinism as mountaineers began to ascend the peaks of the Alps. The Alpine region has a strong cultural identity. Traditional practices such as farming, cheesemaking, and woodworking still thrive in Alpine villages. However, the tourist industry began to grow early in the 20th century and expanded significantly after World War II, eventually becoming

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2976-691: The San Andreas Fault , restraining bends result in regions of localized crustal shortening and mountain building without a plate-margin-wide orogeny. Hotspot volcanism results in the formation of isolated mountains and mountain chains that look as if they are not necessarily on present tectonic-plate boundaries, but they are essentially the product of plate tectonism. Likewise, uplift and erosion related to epeirogenesis (large-scale vertical motions of portions of continents without much associated folding, metamorphism, or deformation) can create local topographic highs. Eventually, seafloor spreading in

3069-736: The Simplon Pass , and the Stelvio Pass . Crossing the Italian-Austrian border, the Brenner Pass separates the Ötztal Alps and Zillertal Alps and has been in use as a trading route since the 14th century. The lowest of the Alpine passes at 985 m (3,232 ft), the Semmering crosses from Lower Austria to Styria ; since the 12th century when a hospice was built there, it has seen continuous use. A railroad with

3162-498: The convergent margins of continents. The convergence may take the form of subduction (where a continent rides forcefully over an oceanic plate to form a noncollisional orogeny) or continental collision (convergence of two or more continents to form a collisional orogeny). Orogeny typically produces orogenic belts or orogens , which are elongated regions of deformation bordering continental cratons (the stable interiors of continents). Young orogenic belts, in which subduction

3255-647: The late Devonian (about 380 million years ago) with the Antler orogeny and continuing with the Sonoma orogeny and Sevier orogeny and culminating with the Laramide orogeny . The Laramide orogeny alone lasted 40 million years, from 75 million to 35 million years ago. Orogens show a great range of characteristics, but they may be broadly divided into collisional orogens and noncollisional orogens (Andean-type orogens). Collisional orogens can be further divided by whether

3348-670: The "Swabian-Bavarian pre-Alps"). In Austria, the Danube runs to the north of the Alps, separating it from the majority of the Bohemian Forest, although some small areas, such as the Dunkelsteiner Wald south of the Wachau , belong geologically to the Bohemian Forest despite being south of the Danube . The Vienna Woods near Vienna forms the north-eastern corner of the Alps, and here the Danube passes at its closest to

3441-615: The 15 km-long (9.3 mi) Saint Gotthard Railway Tunnel was opened connecting Lucerne in Switzerland, with Milan in Italy. 98 years later followed Gotthard Road Tunnel (16.9 km (10.5 mi) long) connecting the A2 motorway in Göschenen on the north side with Airolo on the south side, exactly like the railway tunnel. On 1 June 2016 the world's longest railway tunnel,

3534-664: The 20th century Robert Parker wrote a well-known work about the rock crystals of the Swiss Alps; at the same period a commission was established to control and standardize the naming of Alpine minerals. In the Miocene Epoch the mountains underwent severe erosion because of glaciation, which was noted in the mid-19th century by naturalist Louis Agassiz who presented a paper proclaiming the Alps were covered in ice at various intervals—a theory he formed when studying rocks near his Neuchâtel home which he believed originated to

3627-691: The 29 "four-thousanders" with at least 300 m (984 ft) of prominence. While Mont Blanc was first climbed in 1786 and the Jungfrau in 1811, most of the Alpine four-thousanders were climbed during the second half of the 19th century, notably Piz Bernina (1850), the Dom (1858), the Grand Combin (1859), the Weisshorn (1861) and the Barre des Écrins (1864); the ascent of the Matterhorn in 1865 marked

3720-486: The Alpine region. The cinnabar deposits in Slovenia are a notable source of cinnabar pigments. Alpine crystals have been studied and collected for hundreds of years and began to be classified in the 18th century. Leonhard Euler studied the shapes of crystals, and by the 19th-century crystal hunting was common in Alpine regions. David Friedrich Wiser amassed a collection of 8000 crystals that he studied and documented. In

3813-721: The Alps (see Viennese Basin ). East of Vienna, only the Marchfeld , a 30-km wide flood plain separates the easternmost Alps from the Lesser Carpathians . After Vienna, the Pannonian Basin , a large area of steppe , meets the edge of the Alps, clearly delimiting the eastern limit of the Alps. The south-easternmost extension of the Alps is to be found in Slovenia , including Pohorje , the Kamnik Alps and

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3906-708: The Alps are difficult to quantify and likely to vary significantly in space and time. The Alps are a source of minerals that have been mined for thousands of years. In the 8th to 6th centuries, BC during the Hallstatt culture , Celtic tribes mined copper; later the Romans mined gold for coins in the Bad Gastein area. Erzberg in Styria furnishes high-quality iron ore for the steel industry. Crystals, such as cinnabar , amethyst , and quartz , are found throughout much of

3999-771: The Alps goes back to the Palaeolithic era. A mummified man ("Ötzi") , determined to be 5,000 years old, was discovered on a glacier at the Austrian–Italian border in 1991. By the 6th century BC, the Celtic La Tène culture was well established. Hannibal notably crossed the Alps with a herd of elephants, and the Romans had settlements in the region. In 1800, Napoleon crossed one of the mountain passes with an army of 40,000. The 18th and 19th centuries saw an influx of naturalists, writers, and artists, in particular,

4092-600: The Alps include the Var , Adige and Piave . The triple watershed Rhine-Rhone-Po is south of Furka Pass near the summit of the Witenwasserenstock , at 46°31′N 8°27′E  /  46.517°N 8.450°E  / 46.517; 8.450 ; the triple watershed Rhine-Po-Danube is at Lunghin Pass , Grisons ( 46°25′N 9°39′E  /  46.417°N 9.650°E  / 46.417; 9.650 , 2645 m);

4185-759: The Alps may be easily defined by the passes on either side, defining larger units can be problematic. A traditional divide exists between the Western Alps and the Eastern Alps , which uses the Splügen Pass ( Italian : Passo dello Spluga ) on the Swiss-Italian border, together with the Rhine to the north and Lake Como in the south as the defining features. While the Splügen Pass is neither

4278-399: The Alps" follows the watershed from the Mediterranean to the Wienerwald , passing over many of the highest and most famous peaks in the Alps. The most important passes and peaks which it crosses are given below (mountains are indented, passes unindented). From the Colle di Cadibona to Col de Tende it runs westwards, before turning to the north-west and then, near the Colle de la Maddalena, to

4371-488: The Alps, the longest of which is the aletsch Glacier in the Bernese Alps . They may be found in all of the higher groups of mountains from the Dauphiné Alps in France to the Hohe Tauern in central Austria, and the main ascent routes on many of the highest mountains pass over glaciers. Very few large lakes are found within the body of the Alps, but a number are situated around the edge, particularly in areas formerly covered by glacier tongues. These include Lake Geneva on

4464-434: The Austroalpine peaks underwent an event in the Cretaceous Period, the two areas show distinct differences in nappe formations. Flysch deposits in the Southern Alps of Lombardy probably occurred in the Cretaceous or later. Peaks in France, Italy and Switzerland lie in the "Houillière zone", which consists of basement with sediments from the Mesozoic Era. High "massifs" with external sedimentary cover are more common in

4557-402: The Eastern and South-Western Alps. The underlying mechanisms that jointly drive the present-day uplift pattern are the isostatic rebound due to the melting of the last glacial maximum ice-cap or long-term erosion, detachment of the Western Alpine subducting slab, mantle convection as well as ongoing horizontal convergence between Africa and Europe, but their relative contributions to the uplift of

4650-592: The French–Italian border, and at 4,809 m (15,778 ft) is the highest mountain in the Alps. The Alpine region area contains 128 peaks higher than 4,000 m (13,000 ft) . The altitude and size of the range affect the climate in Europe; in the mountains, precipitation levels vary greatly and climatic conditions consist of distinct zones. Wildlife such as ibex live in the higher peaks to elevations of 3,400 m (11,155 ft), and plants such as edelweiss grow in rocky areas in lower elevations as well as in higher elevations. Evidence of human habitation in

4743-462: The Greek goddess Alphito , whose name is related to alphita , the "white flour"; alphos , a dull white leprosy; and finally the Proto-Indo-European word *albʰós . Similarly, the river god Alpheus is also supposed to derive from the Greek alphos and means whitish. In his commentary on the Aeneid of Virgil , the late fourth-century grammarian Maurus Servius Honoratus says that all high mountains are called Alpes by Celts. According to

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4836-481: The Western Alps and were affected by Neogene Period thin-skinned thrusting whereas the Eastern Alps have comparatively few high peaked massifs. Similarly the peaks in eastern Switzerland extending to western Austria (Helvetic nappes) consist of thin-skinned sedimentary folding that detached from former basement rock. In simple terms, the structure of the Alps consists of layers of rock of European, African, and oceanic (Tethyan) origin. The bottom nappe structure

4929-497: The acceptance of plate tectonics , geologists had found evidence within many orogens of repeated cycles of deposition, deformation, crustal thickening and mountain building, and crustal thinning to form new depositional basins. These were named orogenic cycles , and various theories were proposed to explain them. Canadian geologist Tuzo Wilson first put forward a plate tectonic interpretation of orogenic cycles, now known as Wilson cycles. Wilson proposed that orogenic cycles represented

5022-414: The active front, a forebulge high of flexural origin and a back-bulge area beyond, although not all of these are present in all foreland-basin systems. The basin migrates with the orogenic front and early deposited foreland basin sediments become progressively involved in folding and thrusting. Sediments deposited in the foreland basin are mainly derived from the erosion of the actively uplifting rocks of

5115-525: The alps is the Col de l'Iseran in Savoy (France) at 2,770 m (9,088 ft), followed by the Stelvio Pass in northern Italy at 2,756 m (9,042 ft); the road was built in the 1820s. The Union Internationale des Associations d'Alpinisme (UIAA) has defined a list of 82 "official" Alpine summits that reach at least 4,000 m (13,123 ft). The list includes not only mountains, but also subpeaks with little prominence that are considered important mountaineering objectives. Below are listed

5208-415: The border, with the Jura to the north-west and the Alps to the south east. From Lake Neuchâtel to its confluence with the Rhine , the Aare forms the border. The Black Forest is separated from the Alps by the Rhine and Lake Constance , but exact delimitation is difficult in southern Germany, where the land gently slopes up to meet the mountains (known in German as the Schwäbisch-Bayerisches Alpenvorland ,

5301-744: The central and western portions. The variances in nomenclature in the region spanned by the Alps make classification of the mountains and subregions difficult, but a general classification is that of the Eastern Alps and Western Alps with the divide between the two occurring in eastern Switzerland according to geologist Stefan Schmid, near the Splügen Pass . The highest peaks of the Western Alps and Eastern Alps, respectively, are Mont Blanc, at 4,810 m (15,780 ft), and Piz Bernina , at 4,049 m (13,284 ft). The second-highest major peaks are Monte Rosa , at 4,634 m (15,203 ft), and Ortler , at 3,905 m (12,810 ft), respectively. A series of lower mountain ranges run parallel to

5394-584: The collision is with a second continent or a continental fragment or island arc. Repeated collisions of the later type, with no evidence of collision with a major continent or closure of an ocean basin, result in an accretionary orogen. Examples of orogens arising from collision of an island arc with a continent include Taiwan and the collision of Australia with the Banda arc. Orogens arising from continent-continent collisions can be divided into those involving ocean closure (Himalayan-type orogens) and those involving glancing collisions with no ocean basin closure (as

5487-420: The course of 200 million years in the Paleoproterozoic . The Yavapai and Mazatzal orogenies were peaks of orogenic activity during this time. These were part of an extended period of orogenic activity that included the Picuris orogeny and culminated in the Grenville orogeny , lasting at least 600 million years. A similar sequence of orogenies has taken place on the west coast of North America, beginning in

5580-427: The crust of the continental margin ( thrust tectonics ). This takes the form of folding of the ductile deeper crust and thrust faulting in the upper brittle crust. Crustal thickening raises mountains through the principle of isostasy . Isostacy is the balance of the downward gravitational force upon an upthrust mountain range (composed of light, continental crust material) and the buoyant upward forces exerted by

5673-454: The dense underlying mantle . Portions of orogens can also experience uplift as a result of delamination of the orogenic lithosphere , in which an unstable portion of cold lithospheric root drips down into the asthenospheric mantle, decreasing the density of the lithosphere and causing buoyant uplift. An example is the Sierra Nevada in California. This range of fault-block mountains experienced renewed uplift and abundant magmatism after

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5766-581: The development of geologic concepts during the 19th century, the presence of marine fossils in mountains was explained in Christian contexts as a result of the Biblical Deluge . This was an extension of Neoplatonic thought, which influenced early Christian writers . The 13th-century Dominican scholar Albert the Great posited that, as erosion was known to occur, there must be some process whereby new mountains and other land-forms were thrust up, or else there would eventually be no land; he suggested that marine fossils in mountainsides must once have been at

5859-424: The dominant industry by the end of the century. The Winter Olympic Games have been hosted in the Swiss, French, Italian, Austrian and German Alps. As of 2010, the region is home to 14 million people and has 120 million annual visitors. The English word Alps comes from the Latin Alpes . The Latin word Alpes could possibly come from the adjective albus ("white"), or could possibly come from

5952-406: The edge of the Po Basin , the edge of the Alps is unambiguous, but where the Alps border on other mountainous or hilly regions, the border may be harder to place. These neighbouring ranges include the Apennines , the Massif Central , the Jura , the Black Forest , the Bohemian Forest , the Carpathians , and the mountains of the Balkan Peninsula . The boundary between the Apennines and the Alps

6045-453: The edge of the uplifted layers are exposed. Although mountain building mostly takes place in orogens, a number of secondary mechanisms are capable of producing substantial mountain ranges. Areas that are rifting apart, such as mid-ocean ridges and the East African Rift , have mountains due to thermal buoyancy related to the hot mantle underneath them; this thermal buoyancy is known as dynamic topography . In strike-slip orogens, such as

6138-404: The end of the Mesozoic and continues into the present. The formation of the Alps was a segment of this orogenic process, caused by the collision between the African and the Eurasian plates that began in the late Cretaceous Period. Under extreme compressive stresses and pressure, marine sedimentary rocks were uplifted, forming characteristic recumbent folds , and thrust faults . As

6231-495: The end of the golden age of alpinism . Karl Blodig (1859–1956) was among the first to successfully climb all the major 4,000 m peaks. He completed his series of ascents in 1911. Many of the big Alpine three-thousanders were climbed in the early 19th century, notably the Grossglockner (1800) and the Ortler (1804), although some of them were climbed only much later, such at Mont Pelvoux (1848), Monte Viso (1861) and La Meije (1877). The first British Mont Blanc ascent by

6324-409: The final form of the majority of old orogenic belts is a long arcuate strip of crystalline metamorphic rocks sequentially below younger sediments which are thrust atop them and which dip away from the orogenic core. An orogen may be almost completely eroded away, and only recognizable by studying (old) rocks that bear traces of orogenesis. Orogens are usually long, thin, arcuate tracts of rock that have

6417-406: The lowest nor the most important pass in the Alps, it is approximately halfway along the main chain, and makes a convenient boundary. The Eastern Alps are commonly subdivided according to the different lithology (rock composition) of the more central parts of the Alps and the groups at its northern and southern fringes: The border between the Central Eastern Alps and the Southern Limestone Alps

6510-407: The main chain of the Alps, including the French Prealps in France and the Jura Mountains in Switzerland and France. The secondary chain of the Alps follows the watershed from the Mediterranean Sea to the Wienerwald , passing over many of the highest and most well-known peaks in the Alps. From the Colle di Cadibona to Col de Tende it runs westwards, before turning to the northwest and then, near

6603-489: The mountain range, although some sediments derive from the foreland. The fill of many such basins shows a change in time from deepwater marine ( flysch -style) through shallow water to continental ( molasse -style) sediments. While active orogens are found on the margins of present-day continents, older inactive orogenies, such as the Algoman , Penokean and Antler , are represented by deformed and metamorphosed rocks with sedimentary basins further inland. Long before

6696-821: The mountains in which a valley leads from the plains and hilly pre-mountainous zones. In the medieval period hospices were established by religious orders at the summits of many of the main passes. The most important passes are the Col de l'Iseran (the highest), the Col Agnel , the Brenner Pass , the Mont-Cenis , the Great St. Bernard Pass , the Col de Tende , the Gotthard Pass , the Semmering Pass ,

6789-399: The north. Upon reaching the Swiss border, the line of the main chain heads approximately east-north-east, a heading it follows until its end near Vienna . Some of the highest peaks in the Alps, however, fall to one side or other of the main chain. These include: For more detailed lists of passes, please see the articles about individual areas of the Alps. Several glaciers are located in

6882-684: The northern side of the alps, on the French/Swiss border, Lago Maggiore , Lake Como and Lake Garda on the southern side of the Alps in Italy/Switzerland, and the lakes of Switzerland, southern Germany and the Austrian Salzkammergut in the north. The main drainage basins of the Alps are those of the Rhine , the Rhone , the Danube and the Po . These have as main tributaries: Other important rivers draining

6975-416: The ocean basin comes to a halt, and continued subduction begins to close the ocean basin. The closure of the ocean basin ends with a continental collision and the associated Himalayan-type orogen. Erosion represents the final phase of the orogenic cycle. Erosion of overlying strata in orogenic belts, and isostatic adjustment to the removal of this overlying mass of rock, can bring deeply buried strata to

7068-831: The orogenic events that affected them. The geological subdivision differentiates the Western, Eastern Alps, and Southern Alps: the Helveticum in the north, the Penninicum and Austroalpine system in the centre and, south of the Periadriatic Seam, the Southern Alpine system . According to geologist Stefan Schmid, because the Western Alps underwent a metamorphic event in the Cenozoic Era while

7161-416: The periodic opening and closing of an ocean basin, with each stage of the process leaving its characteristic record on the rocks of the orogen. The Wilson cycle begins when previously stable continental crust comes under tension from a shift in mantle convection . Continental rifting takes place, which thins the crust and creates basins in which sediments accumulate. As the basins deepen, the ocean invades

7254-678: The range's area), Italy (27.2%), France (21.4%), Switzerland (13.2%), Germany (5.8%), Slovenia (3.6%), Liechtenstein (0.08%) and Monaco (0.001%). The highest portion of the range is divided by the glacial trough of the Rhône valley, from Mont Blanc to the Matterhorn and Monte Rosa on the southern side, and the Bernese Alps on the northern. The peaks in the easterly portion of the range, in Austria and Slovenia, are smaller than those in

7347-441: The rift zone, and as the continental crust rifts completely apart, shallow marine sedimentation gives way to deep marine sedimentation on the thinned marginal crust of the two continents. As the two continents rift apart, seafloor spreading commences along the axis of a new ocean basin. Deep marine sediments continue to accumulate along the thinned continental margins, which are now passive margins . At some point, subduction

7440-413: The rising peaks underwent erosion, a layer of marine flysch sediments was deposited in the foreland basin , and the sediments became involved in younger folds as the orogeny progressed. Coarse sediments from the continual uplift and erosion were later deposited in foreland areas north of the Alps. These regions in Switzerland and Bavaria are well-developed, containing classic examples of flysch , which

7533-470: The rock formations of the Alps in the 18th century. In the mid-19th century, the now-defunct idea of geosynclines was used to explain the presence of "folded" mountain chains. This theory was replaced in the mid-20th century by the theory of plate tectonics . The formation of the Alps (the Alpine orogeny ) was an episodic process that began about 300 million years ago. In the Paleozoic Era

7626-491: The sea-floor. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as orogenic in terms of the creation of mountain elevations, as the term mountain building was still used to describe the processes. Elie de Beaumont (1852) used the evocative "Jaws of a Vise" theory to explain orogeny, but was more concerned with the height rather than the implicit structures created by and contained in orogenic belts. His theory essentially held that mountains were created by

7719-414: The squeezing of certain rocks. Eduard Suess (1875) recognised the importance of horizontal movement of rocks. The concept of a precursor geosyncline or initial downward warping of the solid earth (Hall, 1859) prompted James Dwight Dana (1873) to include the concept of compression in the theories surrounding mountain-building. With hindsight, we can discount Dana's conjecture that this contraction

7812-423: The subduction produces compression in the overriding plate. Whether subduction produces compression depends on such factors as the rate of plate convergence and the degree of coupling between the two plates, while the degree of coupling may in turn rely on such factors as the angle of subduction and rate of sedimentation in the oceanic trench associated with the subduction zone. The Andes Mountains are an example of

7905-752: The summer months and where huts and hay barns can be found, sometimes constituting tiny hamlets. Therefore, the term "the Alps", as a reference to the mountains, is a misnomer. The term for the mountain peaks varies by nation and language: words such as Horn , Kogel , Kopf , Gipfel , Spitze , Stock , and Berg are used in German-speaking regions; Mont , Pic , Tête , Pointe , Dent , Roche , and Aiguille in French-speaking regions; and Monte , Picco , Corno , Punta , Pizzo , or Cima in Italian-speaking regions. The Alps are

7998-460: The surface. The erosional process is called unroofing . Erosion inevitably removes much of the mountains, exposing the core or mountain roots ( metamorphic rocks brought to the surface from a depth of several kilometres). Isostatic movements may help such unroofing by balancing out the buoyancy of the evolving orogen. Scholars debate about the extent to which erosion modifies the patterns of tectonic deformation (see erosion and tectonics ). Thus,

8091-656: The triple watershed Po-Danube-Adige is at the Swiss-Italian border, near the summit of Monte Forcola south of Val Müstair , at 46°34′N 10°22′E  /  46.567°N 10.367°E  / 46.567; 10.367 . Alps The Alps ( / æ l p s / ) are one of the highest and most extensive mountain ranges in Europe , stretching approximately 1,200 km (750 mi) across eight Alpine countries (from west to east): Monaco , France , Switzerland , Italy , Liechtenstein , Germany , Austria and Slovenia . The Alpine arch extends from Nice on

8184-464: The use of the term "Alps" to the higher mountains in the centre of the range, relegating the surrounding hills and mountains to the status of "pre-Alps" or foothills . This can sometimes lead to conflicting definitions, such as Mont Ventoux being considered to lie outside the Alps (there are no comparably sized mountains around it, and it is at a considerable distance from the main chain of the Alps). It

8277-539: The various orogenies including exposures of basement rock. Due to the ever-present geologic instability, earthquakes continue in the Alps to this day. Typically, the largest earthquakes in the alps have been between magnitude 6 and 7 on the Richter scale. Geodetic measurements show ongoing topographic uplift at rates of up to about 2.5 mm per year in the North, Western and Central Alps, and at ~1 mm per year in

8370-548: The west in the Bernese Oberland. Because of his work he came to be known as the "father of the ice-age concept" although other naturalists before him put forth similar ideas. Agassiz studied glacier movement in the 1840s at the Unteraar Glacier where he found the glacier moved 100 m (328 ft) per year, more rapidly in the middle than at the edges. His work was continued by other scientists and now

8463-484: The western Mediterranean to Trieste on the Adriatic and Vienna at the beginning of the Pannonian Basin . The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn . Mont Blanc spans

8556-451: Was due to the cooling of the Earth (aka the cooling Earth theory). The cooling Earth theory was the chief paradigm for most geologists until the 1960s. It was, in the context of orogeny, fiercely contested by proponents of vertical movements in the crust, or convection within the asthenosphere or mantle . Gustav Steinmann (1906) recognised different classes of orogenic belts, including

8649-484: Was occasionally used as a name for Scotland , although it is more likely derived from the Latin word albus , the colour white. In modern languages the term alp , alm , albe or alpe refers to a grazing pastures in the alpine regions below the glaciers, not the peaks. An alp refers to a high mountain pasture, typically near or above the tree line , where cows and other livestock are taken to be grazed during

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