Mountain range

Last updated
The Himalayas, the highest mountain range on Earth, seen from space Himalayas.jpg
The Himalayas, the highest mountain range on Earth, seen from space

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.

Contents

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

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)

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]

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]

Climate

The Andes, the world's longest mountain range on the surface of the Earth, have a dramatic impact on the climate of South America Andes 70.30345W 42.99203S.jpg
The Andes, the world's longest mountain range on the surface of the Earth, have a dramatic impact on the climate of South America

The position of mountain ranges 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 (following 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] As a consequence, large mountain ranges, such as the Andes, compartmentalize continents into distinct climate regions.

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 that 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"

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, including the Moon, 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

Orogeny is the primary mechanism by which mountains are formed on continents. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. This leads to both structural deformation and compositional differentiation of the Earth's lithosphere. An orogenic belt or orogen develops as the compressed plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collectively called orogenesis. A synorogenic process or event is one that occurs during an orogeny.

Geology of the Alps The formation and structure of the European Alps

The Alps form part of a Cenozoic orogenic belt of mountain chains, called the Alpide belt, that stretches through southern Europe and Asia from the Atlantic all the way to the Himalayas. This belt of mountain chains was formed during the Alpine orogeny. A gap in these mountain chains in central Europe separates the Alps from the Carpathians to the east. Orogeny took place continuously and tectonic subsidence has produced the gaps in between.

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. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear depression may subsequently be further deepened by the forces of erosion. More generally the valley is likely to be filled with sedimentary deposits derived from the rift flanks and the surrounding areas. In many cases rift lakes are formed. 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 Formation of the Alpine mountain ranges of Europe, the Middle East and northwest Africa

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.

Cryovolcano 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 into an extreme environment at or below their freezing point, essentially reenacting the typical sort of lava volcanism seen on Earth with liquid and frozen volatiles acting as geological allegories to molten and solid rock respectively. 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 the 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.

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.

Chile Triple Junction Place where the South American, Nazca and Antarctic tectonic plates meet

The Chile Triple Junction is a geologic triple junction located on the seafloor of the Pacific Ocean off Taitao and Tres Montes Peninsula on the southern coast of Chile. Here three tectonic plates meet: the South American Plate, the Nazca Plate, and the Antarctic Plate. This triple junction is unusual in that it consists of a mid-oceanic ridge, the Chile Rise, being subducted under the South American Plate at the Peru–Chile Trench. The Chile Triple Junction is the boundary between the Chilean Rise and the Chilean margin, where the Nazca, Antarctic, and South American plates meet at the trench.

Nazca Ridge Submarine ridge off the coast of Peru

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 Russia Overview of the geology of Russia

The geology of Russia, the world's largest country, which extends over much of northern Eurasia, consists of several stable cratons and sedimentary platforms bounded by orogenic (mountain) belts.

A river anticline is a geologic structure that is formed by the focused uplift of rock caused by high erosion rates from large rivers relative to the surrounding areas. An anticline is a fold that is concave down, whose limbs are dipping away from its axis, and whose oldest units are in the middle of the fold. These features form in a number of structural settings. In the case of river anticlines, they form due to high erosion rates, usually in orogenic settings. In a mountain building setting, like that of the Himalaya or the Andes, erosion rates are high and the river anticline's fold axis will trend parallel to a major river. When river anticlines form, they have a zone of uplift between 50-80 kilometers wide along the rivers that form them.

Mons (planetary nomenclature)

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.

Transverse aeolian ridges (TARs) are visually bright features commonly found in topographic depressions on Mars. These small-scale and relict bedforms were first seen in narrow-angle images from the Mars Orbiter Camera (MOC) and were called “ridges” to preserve both dunes and ripples as formative mechanisms. While TARs are widespread on Mars, their formation, age, composition, and role in past Martian sediment cycles remain poorly constrained.

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

River incision

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 WSS:

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.

Earth system interactions across mountain belts

Earth system interactions across mountain belts are interactions between processes occurring in the different systems or "spheres" of the Earth, as these influence and respond to each other through time. Earth system interactions involve processes occurring at the atomic to planetary scale which create linear and non-linear feedback(s) involving multiple Earth systems. This complexity makes modelling Earth system interactions difficult because it can be unclear how processes of different scales within the Earth interact to produce larger scale processes which collectively represent the dynamics of the Earth as an intricate interactive adaptive system.

References

  1. "Definition of mountain system". Mindat.org. Hudson Institute of Mineralogy. Retrieved 26 August 2017.
  2. Rosenberg, Matt. "Pacific Ring of Fire". About.com.
  3. Thorpe, Edgar (2012). The Pearson General Knowledge Manual. Pearson Education India. p. A-36.
  4. Chester, Roy (2008). Furnace of Creation, Cradle of Destruction . AMACOM Div American Mgmt Assn. p.  77.
  5. "Nepal and China agree on Mount Everest's height". BBC. 8 April 2010.
  6. "The mid-ocean ridge is the longest mountain range on Earth". US National Oceanic and Atmospheric Service. 11 Jan 2013.
  7. "Orographic precipitation". Encyclopedia Britannica. Retrieved 23 January 2020.
  8. "A Guide to the Geology of Rocky Mountain National Park, Colorado". USGS. Archived from the original on 2012-10-24.
  9. Egholm, David L.; Knudsen, Mads F.; Sandiford, Mike (2013). "Lifespan of mountain ranges scaled by feedbacks between landslide and erosion by rivers". Nature. 498 (7455): 475–478. Bibcode:2013Natur.498..475E. doi:10.1038/nature12218. PMID   23803847. S2CID   4304803.
  10. Mitri, Giuseppe; Bland, Michael T.; Showman, Adam P.; Radebaugh, Jani; Stiles, Bryan; Lopes, Rosaly M. C.; Lunine, Jonathan I.; Pappalardo, Robert T. (2010). "Mountains on Titan: Modeling and observations". Journal of Geophysical Research. 115 (E10): E10002. Bibcode:2010JGRE..11510002M. doi: 10.1029/2010JE003592 . ISSN   0148-0227. S2CID   12655950.
  11. Gipson, Lillian (24 July 2015). "New Horizons Discovers Flowing Ices on Pluto". NASA . Retrieved 25 July 2015.
  12. Keep, Myra; Hansen, Vicki L. (1994). "Structural history of Maxwell Montes, Venus: Implications for Venusian mountain belt formation". Journal of Geophysical Research. 99 (E12): 26015. Bibcode:1994JGR....9926015K. doi:10.1029/94JE02636. ISSN   0148-0227. S2CID   53311663.
  13. Plescia, J.B. (2003). "Cerberus Fossae, Elysium, Mars: a source for lava and water". Icarus. 164 (1): 79–95. Bibcode:2003Icar..164...79P. doi:10.1016/S0019-1035(03)00139-8. ISSN   0019-1035.
  14. Jaeger, W. L. (2003). "Orogenic tectonism on Io". Journal of Geophysical Research. 108 (E8): 12–1–12–18. Bibcode:2003JGRE..108.5093J. doi: 10.1029/2002JE001946 . ISSN   0148-0227.