Mountain range

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The Himalayas, the highest mountain range on Earth, seen from space Himalayas.jpg
The Himalayas, the highest mountain range on Earth, seen from space
Tatra mountain range Tatra mountain range Poland.jpg
Tatra mountain range

A mountain range or hill range is a series of mountains or hills ranged 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 arisen from the same cause, usually an orogeny. [1] Mountain ranges are formed by a variety of geological processes, but most of the significant ones on Earth are the result of plate tectonics. Mountain ranges are also found on many planetary mass objects in the Solar System and are likely a feature of most terrestrial planets.

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Mountain ranges are usually segmented by highlands or mountain passes and valleys. Individual mountains within the same mountain range do not necessarily have the same geologic structure or petrology. They may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, fold mountains, and volcanic landforms resulting in a variety of rock types.

Major ranges

An 1865 lithograph showing the High Tatras mountain range in Slovakia and Poland by Karel Koristka appearing in a book by August Heinrich Petermann. Vysoke Tatry4b. Gotha, 1865.jpg
An 1865 lithograph showing the High Tatras mountain range in Slovakia and Poland by Karel Kořistka appearing in a book by August Heinrich Petermann.

Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or the Alpide Belt. The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera along the Pacific Coast, the Aleutian Range, on through Kamchatka, Japan, Taiwan, the Philippines, Papua New Guinea, to New Zealand. [2] The Andes is 7,000 kilometres (4,350 mi) long and is often considered the world's longest mountain system. [3]

The Alpide belt includes Indonesia and Southeast Asia, through the Himalaya, Caucasus Mountains, Balkan Mountains fold mountain range, the Alps, and ends in the Spanish mountains and the Atlas Mountains. [4] The belt also includes other European and Asian mountain ranges. The Himalayas contain the highest mountains in the world, including Mount Everest, which is 8,848 metres (29,029 ft) high and traverses the border between China and Nepal. [5]

The Ocean Ridge, the world's longest mountain range (chain) World Distribution of Mid-Oceanic Ridges.gif
The Ocean Ridge, the world's longest mountain range (chain)

Mountain ranges outside these two systems include the Arctic Cordillera, the Urals, the Appalachians, the Scandinavian Mountains, the Great Dividing Range, the Altai Mountains and the Hijaz Mountains. If the definition of a mountain range is stretched to include underwater mountains, then the Ocean Ridges form the longest continuous mountain system on Earth, with a length of 65,000 kilometres (40,400 mi). [6]

Divisions and categories

The mountain systems of the earth are characterized by a tree structure, where mountain ranges can contain sub-ranges. The sub-range relationship is often expressed as a parent-child relationship. For example, the White Mountains of New Hampshire and the Blue Ridge Mountains are sub-ranges of the Appalachian Mountains. Equivalently, the Appalachians are the parent of the White Mountains and Blue Ridge Mountains, and the White Mountains and the Blue Ridge Mountains are children of the Appalachians.

The parent-child expression extends to the sub-ranges themselves: the Sandwich Range and the Presidential Range are children of the White Mountains, while the Presidential Range is a parent to the Northern Presidential Range and Southern Presidential Range.

Climate

The Andes, the world's longest mountain range on the surface of a continent, seen from the air Aerial photo of the Andes.jpg
The Andes, the world's longest mountain range on the surface of a continent, seen from the air

The position of mountains influences climate, such as rain or snow. When air masses move up and over mountains, the air cools producing orographic precipitation (rain or snow). As the air descends on the leeward side, it warms again (in accordance with the adiabatic lapse rate) and is drier, having been stripped of much of its moisture. Often, a rain shadow will affect the leeward side of a range. [7]

Erosion

Mountain ranges are constantly subjected to erosional forces which work to tear them down. The basins adjacent to an eroding mountain range are then filled with sediments which are buried and turned into sedimentary rock. Erosion is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains.

The early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet (3,000 m) of mostly Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to the east. [8] This mass of rock was removed as the range was actively undergoing uplift. The removal of such a mass from the core of the range most likely caused further uplift as the region adjusted isostatically in response to the removed weight.

Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment. Computer simulation has shown that as mountain belts change from tectonically active to inactive, the rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. [9]

Extraterrestrial "Montes"

Hillary and Tenzing Montes on Pluto (14 July 2015) NH-Pluto-SputnikPlanum-HillaryMontes-NorgayMontes-20150714.jpg
Hillary and Tenzing Montes on Pluto (14 July 2015)
Montes Apenninus on the Moon was formed by an impact event. Montes Apenninus AS15-M-1423.jpg
Montes Apenninus on the Moon was formed by an impact event.

Mountains on other planets and natural satellites of the Solar System are often isolated and formed mainly by processes such as impacts, though there are examples of mountain ranges (or "Montes") somewhat similar to those on Earth. Saturn's moon Titan [10] and Pluto, [11] in particular exhibit large mountain ranges in chains composed mainly of ices rather than rock. Examples include the Mithrim Montes and Doom Mons on Titan, and Tenzing Montes and Hillary Montes on Pluto. Some terrestrial planets other than Earth also exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth [12] and Tartarus Montes on Mars, [13] Jupiter's moon Io has mountain ranges formed from tectonic processes including Boösaule Montes, Dorian Montes, Hi'iaka Montes and Euboea Montes. [14]

See also

Related Research Articles

Orogeny The formation of mountain ranges

An orogeny is an event that leads to both structural deformation and compositional differentiation of the Earth's lithosphere at convergent plate margins. An orogen or orogenic belt develops when a continental plate crumples and is pushed upwards to form one or more mountain ranges; this involves a series of geological processes collectively called orogenesis.

Ophiolite Uplifted and exposed oceanic crust

An ophiolite is a section of the Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks.

Island arc Arc-shaped archipelago formed by intense seismic activity of long chains of active volcanoes

Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction zone. They are the principal way by which continental growth is achieved.

Rift valley Linear lowland created by a tectonic rift or fault

A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion. When the tensional forces are strong enough to cause the plate to split apart, a center block drops between the two blocks at its flanks, forming a graben. The drop of the center creates the nearly parallel steeply dipping walls of a rift valley when it is new. That feature is the beginning of the rift valley, but as the process continues, the valley widens, until it becomes a large basin that fills with sediment from the rift walls and the surrounding area. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.

Alpine orogeny orogeny

The Alpine orogeny or Alpide orogeny is an orogenic phase in the Late Mesozoic (Eoalpine) and the current Cenozoic that has formed the mountain ranges of the Alpide belt. These mountains include the Atlas, the Rif, the Baetic Cordillera, the Cantabrian Mountains, the Pyrenees, the Alps, the Apennine Mountains, the Dinaric Alps, the Pindus (Hellenides), the Carpathians, the Balkanides - Balkan Mountains and Rila-Rhodope massifs, the Pontic Mountains, the Taurus, the Armenian Highlands, the Caucasus, the Alborz, the Zagros, the Hindu Kush, the Pamir, the Karakoram, and the Himalayas. Sometimes other names occur to describe the formation of separate mountain ranges: for example Carpathian orogeny for the Carpathians, Hellenic orogeny for the Pindus, Altai orogeny for Altai Mountains or the Himalayan orogeny for the Himalayas.

Cryovolcano A type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock

A cryovolcano is a type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock. Collectively referred to as cryomagma, cryolava or ice-volcanic melt, these substances are usually liquids and can form plumes, but can also be in vapour form. After eruption, cryomagma is expected to condense to a solid form when exposed to the very low surrounding temperature. Cryovolcanoes may potentially form on icy moons and other objects with abundant water past the Solar System's snow line. A number of features have been identified as possible cryovolcanoes on Pluto, Titan and Ceres, and a subset of domes on Europa may have cryovolcanic origins. In addition, although they are not known to form volcanoes, ice geysers have been observed on Enceladus and potentially Triton.

Alpide belt mountain

The Alpide belt or Alpine-Himalayan orogenic belt is a seismic belt and orogenic belt that includes an array of mountain ranges extending for more than 15,000 km along the southern margin of Eurasia, stretching from Java and Sumatra, through the Indochinese Peninsula, the Himalayas and Transhimalayas, the mountains of Iran, Caucasus, Anatolia, the Mediterranean, and out into the Atlantic. It includes, from west to east, the major ranges of the Atlas Mountains, the Alps, the Caucasus Mountains, Alborz, Hindu Kush, Karakoram, and the majestic Himalayas. It is the second most seismically active region in the world, after the circum-Pacific belt, with 17% of the world's largest earthquakes.

Erosion and tectonics

The interaction between erosion and tectonics has been a topic of debate since the early 1990s. While the tectonic effects on surface processes such as erosion have long been recognized, the opposite has only recently been addressed. The primary questions surrounding this topic are what types of interactions exist between erosion and tectonics and what are the implications of these interactions. While this is still a matter of debate, one thing is clear, the Earth's landscape is a product of two factors: tectonics, which can create topography and maintain relief through surface and rock uplift, and climate, which mediates the erosional processes that wear away upland areas over time. The interaction of these processes can form, modify, or destroy geomorphic features on the Earth's surface.

The Maria fold and thrust belt (MFTB) is a portion of the North American Cordillera orogen in which geological structures accommodate roughly north–south to northwest-southeast vergent Mesozoic age crustal shortening. This lies in contrast to the remainder of the Cordillera, in which shortening is predominantly east–west. Structures associated with the Maria Fold and Thrust Belt are exposed in a series of mountain ranges in southeastern California and western Arizona. Many of the deep structures of the MFTB have been exposed due to east–west to northeast-southwest Cenozoic age extension and unroofing.

Nazca Ridge A submarine ridge on the Nazca Plate off the west coast of South America

The Nazca Ridge is a submarine ridge, located on the Nazca Plate off the west coast of South America. This plate and ridge are currently subducting under the South American Plate at a convergent boundary known as the Peru-Chile Trench at approximately 7.7 cm (3.0 in) per year. The Nazca Ridge began subducting obliquely to the collision margin at 11°S, approximately 11.2 Ma, and the current subduction location is 15°S. The ridge is composed of abnormally thick basaltic ocean crust, averaging 18 ±3 km thick. This crust is buoyant, resulting in flat slab subduction under Peru. This flat slab subduction has been associated with the uplift of Pisco Basin and the cessation of Andes volcanism and the uplift of the Fitzcarrald Arch on the South American continent approximately 4 Ma.

Andean orogeny Ongoing mountain-forming process in South America

The Andean orogeny is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system along the western margin of South America. On a continental scale the Cretaceous and Oligocene were periods of re-arrangements in the orogeny. Locally the details of the nature of the orogeny varies depending on the segment and the geological period considered.

Geology of North America regional geology of North America

The geology of North America is a subject of regional geology and covers the North American continent, third-largest in the world. Geologic units and processes are investigated on a large scale to reach a synthesized picture of the geological development of the continent.

Doom Mons mountain on Titan

Doom Mons is the name of a mountain range and its eponymous peak on Titan, the largest moon of Saturn. A putative cryovolcano, it is the largest mountain range on Titan by volume, and its 1.45 km-high peak one of the highest. It was discovered by the Cassini–Huygens probe in 2005 and officially named in 2012.

Mons (planetary nomenclature) mountain on a celestial body

Mons is a mountain on a celestial body. The term is used in planetary nomenclature: it is a part of the international names of such features. It is capitalized and usually stands after the proper given name, but stands before it in the case of lunar mountains.

In geology, the term exhumation refers to the process by which a parcel of rock, approaches Earth's surface.

River incision narrow erosion caused by a river or stream

River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected plateau. River Incision is the natural process by which a river cuts downward into its bed, deepening the active channel. Though it is a natural process, it can be accelerated rapidly by human factors including land use changes such as timber harvest, mining, agriculture, and road and dam construction. The rate of incision is a function of basal shear-stress. Shear stress is increased by factors such as sediment in the water, which increase its density. Shear stress is proportional to water mass, gravity, and Sw, where t= Shear Stress (N/m2), g= Weight Density of Water, D = Average water depth, and Sw = Water Surface slope. Increases in slope, depth, or density of water increase the water's potential to cause erosion.

Heat-pipe tectonics is a cooling mode of terrestrial planets in which the main heat transport mechanism in the planet is volcanism through the outer hard shell, also called the lithosphere. Heat-pipe tectonics initiates when volcanism becomes the dominant surface heat transfer process. Melted rocks and other more volatile planetary materials are transferred from the mantle to surface via localised vents. Melts cool down and solidify forming layers of cool volcanic materials. Newly erupted materials deposit on top of and bury older layers. The accumulation of volcanic layers on the shell and the corresponding evacuation of materials at depth cause the downward transfer of superficial materials such that the shell materials continuously descend toward the planet's interior.

Paleogeography of the India–Asia collision system Geological and geomorphological evolution of India and Asia

The paleogeography of the India–Asia collision system is the reconstructed geological and geomorphological evolution within the collision zone of the Himalayan orogenic belt. The continental collision between the Indian and Eurasian plate is one of the world's most renowned and most studied convergent systems. However, many mechanisms remain controversial. Some of the highly debated issues include the onset timing of continental collision, the time at which the Tibetan plateau reached its present elevation and how tectonic processes interacted with other geological mechanisms. These mechanisms are crucial for the understanding of Mesozoic and Cenezoic tectonic evolution, paleoclimate and paleontology, such as the interaction between the Himalayas orogenic growth and the Asian monsoon system, as well as the dispersal and speciation of fauna. Various hypotheses have been put forward to explain how the paleogeography of the collision system could have developed. Important ideas include the synchronous collision hypothesis, the Lhasa-plano hypothesis and the southward draining of major river systems.

References

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  7. "Orographic precipitation". Encyclopedia Britannica. Retrieved 23 January 2020.
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