| Alpide belt | |
|---|---|
| Alpine-Himalayan orogenic belt | |
 Approximate extent of the Alpide orogenic system | |
| Highest point | |
| Peak | Mount Everest |
| Elevation | 8,848.86 m (29,031.7 ft) |
| Dimensions | |
| Length | 15,000 km (9,300 mi) E–W in the west, N–S in the east |
| Naming | |
| Etymology | Derived fromAlps |
| Geography | |
 | |
| Mesozoic oceanic platform | Southern Eurasia, northern Africa, central Asian subcontinent, southeast Asia |
| Geology | |
| Formed by | compressive forces at aligned convergent plate boundaries |
| Orogenies | Alpine (in west),Himalayan (in east) |
| Mountain type | Folded mountain ranges |
TheAlpide belt orAlpine-Himalayan orogenic belt orAlpine-Persia–Tibet–Burma orogeny,[1] or more recently and rarelythe Tethyan orogenic belt, is aseismic andorogenic belt that includes an array ofmountain ranges extending for more than 15,000 kilometres (9,300 mi) along the southern margin ofEurasia, stretching fromJava andSumatra, through theIndochinese Peninsula, theHimalayas andTranshimalayas, themountains of Iran,Caucasus,Anatolia, theMediterranean, and out into theAtlantic.[2]
It includes, from west to east, the major ranges of theAtlas Mountains, theAlps, theCaucasus Mountains,Alborz,Hindu Kush,Karakoram, and theHimalayas. It is the second most seismically active region in the world, after the circum-Pacific belt (theRing of Fire), with 17% of the world's largest earthquakes.[2]
The belt is the result ofMesozoic-to-Cenozoic-to-recent closure of theTethys Ocean and process of collision between the northward-movingAfrican,Arabian, andIndian plates with theEurasian plate.[1] Each collision results in aconvergent boundary, a topic covered inplate tectonics. The approximate alignment of so many convergent boundaries trending east to west, first noticed by the Austrian geologistEduard Suess, suggests thatonce many plates were one plate, and the collision formed one subduction zone, which was oceanic, subducting the floor of Tethys.[citation needed]
Suess called the single continentGondwana, after some rock formations in India, then part of the supercontinent of Gondwana, which had earlier divided from another supercontinent,Laurasia, and was now pushing its way back. Eurasia descends from Laurasia, the Laurentia part having split away to the west as a consequence of the formation of the North Atlantic Ocean. As Tethys closed, Gondwana pushed up mountain ranges on the southern margin of Eurasia.
The Alpide belt is a concept from modernhistorical geology, the study in geologic time of the events that shaped the surface of the Earth.[3] The topic began suddenly in the mid-19th century with the evolutionary biologists. The early historical geologists, such asCharles Darwin andCharles Lyell, arranged fossils and layers of sedimentary rock containing them into time periods, of which the framework remains.[4]
The late 19th century was a period of synthesis, in which geologists attempted to combine all the detail into the big picture. The first of his type,Eduard Suess, used the term "comparative orography" to refer to his method of comparing mountain ranges, parallel to "comparative anatomy" and "comparative philology.[4]
His work preceded plate tectonics and continental drift. This pre-tectonic phase lasted until about 1950, when the drift theory won the field just as suddenly as had the evolutionist. The concepts and language of the comparative graphists were kept with some modification, but were explained in new ways.
The author of the concept of a trans-Eurasian zone ofsubsidence, which he calledTethys, wasEduard Suess. He knew it had been a subsidence because it expressed deposits of theMesozoic, now indurated into layers and raised into highlands by compressional force.[5] Suess had discovered the zone during his early work on theAlps. He spent the better part of his career following the zone in detail, which he assembled in one ongoing work,das Antlitz der Erde, "The Face of the Earth." Like a human face, the Earth's face haslineaments. Suess's topic was the definition and classification of the lineaments of this zone, which he traced from one end of Eurasia to the other, ending on the east with theMalay Peninsula.
Suess looked, as did all geologists, at the strata and content ofsedimentary rock, deposited as sediment in the oceanic basins, indurated under the pressure of the depths, and raised later under horizontal pressure into folds of mountain chains. What he added to the field is the study of what he called the "trend-lines" or directions of mountains chains. These were to be discovered by examining theirstrikes, or intersections with the surface. He soon discovered what are known today as convergent plate borders, which are chains of mountains raised by the compression or subduction of one plate under another, but knowledge was not in such a state that he could recognize them as that. He concerned himself instead with the patterns.
Indonesia lies between the PacificRing of Fire along the northeastern islands adjacent to and includingNew Guinea and the Alpide belt along the south and west fromSumatra,Java and theLesser Sunda Islands (Bali,Flores, andTimor). The2004 Indian Ocean earthquake just off the coast of Sumatra was located within the Alpide belt.
The wordAlpide is a term first coined in German by Austrian geologistEduard Suess in his 1883 magnum opusDas Antlitz der Erde[6] and later popularized in English-language scientific literature by Turkish geologist and historianA. M. Celâl Şengör in a 1984 paper on the topic.[7] The term adds the suffix-ides, derived from the Ancient Greek patronymic/familial suffix-ίδης (-ídēs), to theAlps, suggesting a "family" of related orogens. The termbelt refers to the fact that the Alpides form a long, mostly unbroken chain of orogens running west to east along the southern edge of Eurasia.
If "Alpide" is taken in Kober's sense to mean the last and current of a collective group of contemporaneous ridges over the entire Tethyan region, then "Alpine orogeny" is used collectively of all the orogenies required to create the Alpides, a definition that is far from the original meanings of Alpide and Alpine, representing a specialized geologic usage.
Die zweite Aenderung besteht darin, dass nun die Ketten, welche jünger sind als das Ober-Carbon oder Perm, sich räumlich scharf abtrennen. Sie liegen fast ganz innerhalb von Senkungen der Altaiden, umrahmt von Linien, die nicht selten das Streichen der Altaiden durchschneiden. Man kann diese umrahmten Ketten als posthume Altaiden ansehen. Die alpinen Ketten (Alpiden) sind ihr wichtigstes Glied. DieAlpiden besitzen einen tertiären Saum. Im variscischen Aussenrande, z. B. ausserhalb der belgischen Kohlenfelder, sieht man nichts Aehnliches. Ueberhaupt ist jüngere Faltung in den Horsten der europäischen Altaiden nur gar selten und in geringem Maasse sichtbar. Es ist, als wäre der Rahmen erstarrt, und die Faltung vom Ober-Carbon an auf die gesenkten Räume eingeschränkt.[In the next place those chains of the Altaides which are younger than the upper Carboniferous and the Permian are separated sharply in space. They lie almost wholly within subsided areas of the Altaides, framed in by lines which frequently cut across the strike of these mountains. We may regard the chains thus framed in as posthumous Altaides. The Alpine chains (Alpides) are their most important member. TheAlpides are bordered by a Tertiary zone. Nothing analogous to this is to be seen in the outer margin of the Variscan arc, i.e. outside the Belgian coal-fields. Indeed the younger folding occurs but seldom in the horsts of the European Altaides, and is then only feebly developed. It is as though the frame had become rigid, and the folding, from the upper Carboniferous onwards, had been confined to the downthrown areas. (translated by Hertha B. C. Sollas, under the direction of W. C. Sollas, 1909)]
Figure 7 shows the present extent of the orogenic system related to the obliteration of Paleo-Tethys as compared with that generated during the closure of Neo-Tethys. I call the former the Cimmerides (Figure 7B, I); the latter I define to constitute theAlpides (Figure 7B, II). The Cimmerides and theAlpides may be defined to form the Tethysides, for they both descended from Tethys s.l. (Figure 7A). The Alpine-Himalayan mountain belt therefore consists of two mutually independent, but largely superimposed orogenic complexes (Figure 7A).
