Altiplano-Puna Plateau: Altiplano Basin (South America)

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Altiplano-Puna Plateau: Altiplano Basin (South America)

Thu, 04/04/2019 - 17:32

The Altiplano is a high plateau region in west-central South America where the Andes are the widest. The bulk of the Altiplano-Puna plateau lies in Bolivia, its northern parts in Peru, and its southern parts in Chile and Argentina. The Altiplano Basin is a sedimentary basin located on the plateau.

Altiplano-Puna Plateau

The Altiplano is a high plateau region in west-central South America where the Andes Mountains are the widest. It is the most extensive area of high plateau outside Tibet. The Altiplano is often called the Altiplano-Puna plateau, where "Puna" refers to the high-altitude grassland region covering much of the tableland.

The bulk of the Altiplano lies in Bolivia, its northern parts in Peru, and its southern parts in Chile and Argentina. It is a series of intermontane basins lying about 3,650 m (12,000 ft) above sea level.

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 Cordillera Oriental of the Bolivian Andes forms the eastern boundary of the Altiplano. Lake Titicaca occupies the northernmost part of the plateau. To the south are Lake Poopó and the Coipasa and Uyuni salt flats.

To the northeast is the Cordillera Real with Illampu (6,368 m or 20,892 ft), Huayna Potosí (6,088 m or 19,973 ft), Janq'u Uma (6,427 m or 21,086 ft) and Illimani (6,438 m or 21,122 ft). On the eastern side of the Altiplano, there is a continuous passageway of gentle gradient extending southward across Bolivia.

The Altiplano is dominated by massive active volcanoes of the Central Volcanic Zone to the west, such as Ampato (6,288 m or 20,630 ft), Tutupaca (5,816 m or 19,081 ft), Parinacota (6,348 m or 20826 ft), Guallatiri (6,071 m or 19,918 ft), Paruma (5,728 m or 18,792 ft), Uturunku (6,008 m or 19,711 ft) and Licancabur (5,916 m or 19,409 ft). The Altiplano-Puna volcanic complex is a significant caldera and silicic ignimbrite volcanic field located in the southern portion of the plateau.

The plateau hosts several cities, including El Alto, La Paz and Oruro in Bolivia and Puno in Peru. Major economic activities in the Altiplano include llama and vicuña herding (bred for wool and served as pack animals), mining, and city services. The region was the site of several pre-Columbian cultures, including the Chiripa, Tiwanaku and the Inca Empire. The dominant vegetation consists of grass and shrubs. The region's wildlife originally included the alpaca and the llama.

Map showing the location (in red) of the Altiplano-Puna plateau in South America

Map showing the location (in red) of the Altiplano Plateau in South America

Altiplano Basin

The Altiplano Basin is a sedimentary basin located on the Altiplano-Puna plateau between the Cordillera Occidental and the Cordillera Oriental with an approximate size of 154,176 s km (59,528 sq mi) that formed at varying rates over geological time.

The Cordillera Occidental overrides the northern part of the basin along the Pasani Fault. To the east, the north part of the basin was overridden by the Cordillera Oriental along the Ayaviri Fault. Further south, the basin's boundary with the Cordillera Oriental block comprises the largely buried Coniri Fault.

Overall, the basin has evolved through time in the context of the horizontal shortening of Earth's crust. The great thickness of the sediments accumulated in the basin is primarily the result of the erosion of the Cordillera Oriental.

Map depicting the approximate extent of the sedimentary basin in the Altiplano.

Map depicting the approximate extent of the sedimentary basin in the Altiplano.