Altiplano

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Location of the Altiplano in South America Altiplano map.png
Location of the Altiplano in South America
La Paz, Bolivia, is the largest city located in the Altiplano La Paz Skyline.jpg
La Paz, Bolivia, is the largest city located in the Altiplano
Volcanoes in Sajama National Park (Parinacota and Pomerape) SajamaPark.jpg
Volcanoes in Sajama National Park (Parinacota and Pomerape)

The Altiplano (Spanish for "high plain"), Collao (Quechua and Aymara: Qullaw, meaning "place of the Qulla") or Andean Plateau, in west-central South America, is the area where the Andes are the widest. It is the most extensive area of high plateau on Earth outside Tibet. The bulk of the Altiplano lies in Bolivia, but its northern parts lie in Peru, and its southern parts lie in Chile and Argentina.

Contents

The plateau hosts several cities of these four nations, including El Alto, La Paz, Oruro, and Puno. The northeastern Altiplano is more humid than the southwestern area. The latter area has several salares, or salt flats, due to its aridity. At the Bolivia–Peru border lies Lake Titicaca, the largest lake in South America. South of that in Bolivia was Lake Poopó, which was declared dried up and defunct as of December 2015. It is unclear if this second-largest lake in Bolivia can be revitalized. [1] [2]

The Altiplano was the site of several pre-Columbian cultures, including the Chiripa, Tiawanaku and the Inca Empire. Spain conquered the region in the 16th century.

Major economic activities in the Altiplano include mining, llama and vicuña herding, and services in the cities. There is some international tourism.

Location

A map of the endorheic river basins that characterize the altiplano. In the north is Lake Titicaca and the Desaguadero River system; in the south is the Salar de Uyuni salt flat. The non-endorheic altiplano extends southward into Argentina and Chile. Mapa cuencas endorreicas meseta del collao.jpg
A map of the endorheic river basins that characterize the altiplano. In the north is Lake Titicaca and the Desaguadero River system; in the south is the Salar de Uyuni salt flat. The non-endorheic altiplano extends southward into Argentina and Chile.

The Altiplano is an area of inland drainage (endorheism) lying in the central Andes, occupying parts of northern Chile and Argentina, western Bolivia and southern Peru. Its height averages about 3,750 meters (12,300 feet), [3] slightly less than that of the Tibetan Plateau. Unlike conditions in Tibet, the Altiplano is dominated by massive active volcanoes of the Central Volcanic Zone to the west, such as Ampato (6288 m), Tutupaca (5,816 m), Parinacota (6348 m), Guallatiri (6071 m), Paruma (5,728 m), Uturunku (6,008 m) and Licancabur (5,916 m), and the Cordillera Real in the north east with Illampu (6,368 m), Huayna Potosí (6,088 m), Janq'u Uma (6,427 m) and Illimani (6,438 m). [4] The Atacama Desert, one of the driest areas on the planet, lies to the southwest of the Altiplano; to the east lies the humid Amazon rainforest.

The Altiplano is noted for hypoxic air caused by very high elevation.

History

At various times during the Pleistocene epoch, both the southern and northern Altiplano were covered by vast pluvial lakes. Remnants are Lake Titicaca, straddling the Peru–Bolivia border, and Poopó, a salt lake that extends south of Oruro, Bolivia. Salar de Uyuni , locally known as Salar de Tunupa, and Salar de Coipasa are two large dry salt flats formed after the Altiplano paleolakes dried out.

Climatic zones

The Bolivian Altiplano at about 4,250 m (14,000 feet). The snow-covered peaks of the Cordillera Real rise in the background. Altiplano.jpg
The Bolivian Altiplano at about 4,250 m (14,000 feet). The snow-covered peaks of the Cordillera Real rise in the background.

The term Altiplano is sometimes used to identify the altitude zone and the type of climate that prevails within it: it is colder than that of the tierra fría but not as cold as that of the tierra helada. Scientists classify the latter as commencing at an elevation of approximately 4,500 meters (or about 15,000 feet). Alternate names used in place of altiplano in this context include puna and páramos.

Climate

In general the climate is cool and humid to semi-arid and even arid, with mean annual temperatures that vary from 3 °C (37.4 °F) near the western mountain range to 12 °C (53.6 °F) near Lake Titicaca; and total annual rainfall that ranges between less than 200 mm to the south west to more than 800 mm near and over Lake Titicaca. The diurnal cycle of temperature is very wide, with maximum temperatures in the order of 12 to 24 °C (53.6 to 75.2 °F) and the minimum in the order of -20 to 10 °C (-4 to 50 °F).[ citation needed ]

The coldest temperatures occur in the southwestern portion of the Altiplano during the months of June and July, which correspond to the austral winter. The seasonal cycle of rainfall is marked, with the rainy season concentrated between December and March. The rest of the year tends to be very dry, cool, windy and sunny. Snowfall may happen between April and September, especially to the north, but it is not very common (between one and five times a year).

Altiplano Panorama.jpg
Panorama of Peruvian Altiplano.

Geology

A rock sculpted by wind erosion (or Aeolian processes) in the Bolivian Altiplano. Arbol de Piedra.jpg
A rock sculpted by wind erosion (or Aeolian processes) in the Bolivian Altiplano.

Several mechanisms have been put forth for the formation of the Altiplano plateau; hypotheses try to explain why the topography in the Andes incorporates this large area of low relief at high altitude (high plateau) within the orogen:

  1. Existence of weaknesses in the Earth's crust prior to tectonic shortening. Such weaknesses would cause the partition of tectonic deformation and uplift into the eastern and western cordillera, leaving the necessary space for the formation of the altiplano basin.
  2. Magmatic processes rooted in the asthenosphere might have contributed to uplift of the plateau
  3. Climate has controlled the spatial distribution of erosion and sediment deposition, controlling the lubrication along the subducting Nazca Plate and hence influencing the transmission of tectonic forces into South America.
  4. Climate also determined the formation of internal drainage (endorheism) and sediment trapping within the Andes, potentially blocking tectonic deformation in the central area between the two cordilleras, and expelling deformation towards the flanks of the orogen [5]
  5. Convective removal of the dense lower lithosphere beneath the Altiplano caused that region to isostatically 'float' higher

Communities

See also

Related Research Articles

Andes Mountain range in South America

The Andes or Andean Mountains are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The Andes also have the 2nd most elevated highest peak of any mountain range, only behind the Himalayas. The range is 7,000 km (4,300 mi) long, 200 to 700 km wide, and has an average height of about 4,000 m (13,000 ft). The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina.

Geography of Bolivia

The geography of Bolivia includes the Eastern Andes Mountain Range which bisects Bolivia roughly from north to south. To the east of that mountain chain are lowland plains of the Amazon Basin, and to the west is the Altiplano which is a highland plateau where Lake Titicaca is located. Bolivia's geography has features similar to those of Peru which abuts Bolivia's northwest border; like Bolivia, Peru is bisected from north to south by the Eastern Andes Mountains, and these two countries share Lake Titicaca which is the highest navigable lake on Earth. Unlike Peru, however, Bolivia is one of the two landlocked countries in South America, the other being Paraguay which is located along Bolivia's southeast border.

Lake Titicaca lake in Peru and Bolivia

Titicaca is a large, deep lake in the Andes on the border of Bolivia and Peru, often called the "highest navigable lake" in the world. By volume of water and by surface area, it is the largest lake in South America. Lake Maracaibo has a larger surface area, but it is a tidal bay, not a lake.

Plateau An area of a highland, usually of relatively flat terrain

In geology and physical geography, a plateau, also called a high plain or a tableland, is an area of a highland, usually consisting of relatively flat terrain, that is raised significantly above the surrounding area, often with one or more sides with deep hills. Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental.A few plateau's may have a small flat top while others have wide ones.

Lake Poopó salt lake

Lake Poopó is a large saline lake located in a shallow depression in the Altiplano Mountains in Oruro Department, Bolivia, at an altitude of approximately 3,700 m (12,100 ft). Because the lake was long and wide, it made up the eastern half of the department, known as a mining region in southwest Bolivia. The permanent part of the lake body covered approximately 1,000 square kilometres (390 sq mi) and it was the second-largest lake in the country. The lake received most of its water from the Desaguadero River, which flows from Lake Titicaca at the north end of the Altiplano. Since the lake lacked any major outlet and had a mean depth of less than 3 m (10 ft), the surface area differed greatly on a seasonal basis.

Puna grassland

The Puna grassland ecoregion, of the montane grasslands and shrublands biome, is found in the central Andes Mountains of South America. It is considered one of the eight Natural Regions in Peru, but extends south, across Bolivia, as far as northern Argentina and Chile. The term puna encompasses diverse ecosystems of the high Central Andes above 3200–3400 m.

Norte Grande

The Norte Grande is one of the five natural regions into which CORFO divided continental Chile in 1950. It borders Peru to the north, the Pacific Ocean to the west, the Altiplano, Bolivia and Argentina to the east, and the Copiapó River to the south, beyond which lies the Norte Chico natural region.

Central Andean dry puna

The Central Andean dry puna (NT1001) is an ecoregion in the Montane grasslands and shrublands biome, located in the Andean high plateau, in South America. It is a part of the Puna grassland.

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 Bolivia

The geology of Bolivia comprises a variety of different lithologies as well as tectonic and sedimentary environments. On a synoptic scale, geological units coincide with topographical units. The country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields. The Bolivian Andes is divided into three main ranges; these are from west to east: the Cordillera Occidental that makes up the border to Chile and host several active volcanoes and geothermal areas, Cordillera Central once extensively mined for silver and tin and the relatively low Cordillera Oriental that rather than being a range by its own is the eastern continuation of the Central Cordillera as a fold and thrust belt. Between the Occidental and Central Cordillera the approximately 3,750-meter-high Altiplano high plateau extends. This basin hosts several freshwater lakes, including Lake Titicaca as well as salt-covered dry lakes that bring testimony of past climate changes and lake cycles. The eastern lowlands and sub-Andean zone in Santa Cruz, Chuquisaca, and Tarija Departments was once an old Paleozoic sedimentary basin that hosts valuable hydrocarbon reserves. Further east close to the border with Brazil lies the Guaporé Shield, made up of stable Precambrian crystalline rock.

Altiplano Basin sedimentary basin within the Andes in Bolivia and Peru

The Altiplano Basin is a sedimentary basin within the Andes in Bolivia and Peru. The basin is located on the Altiplano plateau between the Cordillera Occidental and the Cordillera Oriental. Over-all the basin has evolved through time in a context of horizontal shortening of Earth's crust. The great thickness of the sediments accumulated in the basin is mostly the result of the erosion of Cordillera Oriental.

Lake Minchin

Lake Minchin is a name of an ancient lake in the Altiplano of South America. It existed where today the Salar de Uyuni, Salar de Coipasa and Lake Poopó lie. It was formerly considered the highest lake in the Altiplano but research indicated that the highest shoreline belongs to the later Lake Tauca instead.

Lake Tauca former lake in Bolivia, parts of it extended into Chile

Lake Tauca is a former lake in the Altiplano of Bolivia. It is also known as Lake Pocoyu for its constituent lakes: Lake Poopó, Salar de Coipasa and Salar de Uyuni. The lake covered large parts of the southern Altiplano between the Eastern Cordillera and the Western Cordillera, covering an estimated 48,000 to 80,000 square kilometres of the basins of present-day Lake Poopó and the Salars of Uyuni, Coipasa and adjacent basins. Water levels varied, possibly reaching 3,800 metres (12,500 ft) in altitude. The lake was saline. The lake received water from Lake Titicaca, but whether this contributed most of Tauca's water or only a small amount is controversial; the quantity was sufficient to influence the local climate and depress the underlying terrain with its weight. Diatoms, plants and animals developed in the lake, sometimes forming reef knolls.

Inca Huasi was a paleolake in the Andes. It was named by a research team in 2006.

Salinas is a lake event in the Salar de Uyuni, Bolivia.

Ouki was an ancient lake in the Bolivian Altiplano. Its existence was postulated in 2006 by a group of scientists which had subdivided the Lake Minchin lake cycle in several subcycles. The Lake Minchin cycle had been previously identified in 1904 as a now disappeared lake in the central Altiplano. Sediments attributed to Lake Minchin may be part of Ouki instead. The dating is uncertain, with radiocarbon and uranium-thorium dating yielding different dates spanning the time between 28,200 and 125,990 ± 9,580 years ago.

Sajsi is the name of an ancient lake in the Andes

Lake Mataro is an ancient lake in the Andes. It formed over the northern Altiplano at an altitude of 3,950 metres (12,960 ft) and extended over the central Altiplano. It is one of the ancient lakes of the Altiplano like Lake Minchin, Lake Ballivian and Lake Cabana. It existed between 2.8 and 1.8 million years ago.

Lake Ballivián is an ancient lake in the Altiplano of South America and is named after the Bolivian scholar Don Manuel Vicente Ballivian. It is part of a series of lakes which developed in the Titicaca basin along with Lake Mataro and Lake Cabana, reaching an altitude of 3,860 metres (12,660 ft). Lake Ballivián itself is of late Quaternary age and may have influenced the spread and development of animals in the Altiplano. In the southern Altiplano, Lake Escara may be coeval with Lake Ballivián.

References

  1. Mercado, David. "Lake Poopo Dries Up". Reuters. Archived from the original on 19 December 2015.
  2. Paskevics, Emily (19 December 2015). "Lake Poopó, Second Largest In Bolivia, Dries Up Completely". Headlines & Global News (HNGN). Archived from the original on 9 February 2016.
  3. "The Use of Solar Energy for Improving the Living Conditions in Altiplano/Argentina" (PDF). Archived from the original (PDF) on 2011-07-19. Retrieved 2009-10-10.
  4. Andes map
  5. Garcia-Castellanos, D., 2007. The role of climate during high plateau formation. Insights from numerical experiments. Earth Planet. Sci. Lett. 257, 372-390, doi : 10.1016/j.epsl.2007.02.039.

Coordinates: 16°00′13″S69°39′12″W / 16.00358°S 69.65332°W / -16.00358; -69.65332