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South America Geology

South America is located on the South American Plate, which also includes the ocean floor in the South Atlantic Ocean up to the rift in the Mid-Atlantic Ridge. The seabed spread here leads the plate west towards an east-sloping subduction zone off the west coast of South America, where the oncoming and faster Nazca plate sinks below the volcanically and seismically active Andes. Off the coast of southern Chile, the ridge south of the Nazca Plateau and parts of the Antarctic Plateau descend into the subduction zone; see plate tectonics.

South American Plate

The South American Plate emerged as an independent plate during the breakup of the Gondwana continent, when a Jurassic rift zone for approximately 150-200 million years ago, South America split from Africa, and seabed dispersal began. Therefore, the continental slopes have the same course in the two continents, and layer series deposited before the separation show great similarities. It originally gave rise to the theory of continental drift. During the rift stage, diamond-bearing kimberlite rocks also formed in both continents. While South America was still part of Gondwana, other Pacific ocean floor plates were lowered into the subduction zone west of South America, forming a primitive, magmatic arch in the upper plate, where material from the arch was deposited as thick turbidite sequences in front of the continent. These first volcanic “Andes” rested on the ocean floor crust. However, conditions changed for approximately 100 million years ago, when an intensified seabed dispersal in the South Atlantic increased the plate’s westward drift. Large amounts of andesitic magma thus rose from the subduction zone, volcanism increased, batholiters formed and a thick continental crust. This caused the tectonic tensions to be unleashed along the Andes’ island coast. The crust below the eastern foreland was sheared to the west, and eastward overlying cover covers developed in the Precordillas and a central folding and overhanging belt.

The rest of South America includes several sediment basins, platforms and bedrock shields. The deep basins up towards the Andes as well as the Amazon, Parnaibo and Paraná basins are filled with thick post-Triassic lava and sediment sequences. The older platform sediments from the Silurian Triassic, like the Gondwana deposits in Africa, include early Silurian and Late Carbon deposits, shales with plant fossils from the Glossopteris flora, and freshwater layers of mesosaurs. The Southern Patagonian Platform is believed to have hercynically folded foundations. The bedrock of pre-Cambrian South America, the Amazon, is exposed in the Guyana Shield, the Central Brazilian Shield, and the Atlantic Shield. Between 3200 and 550 mill. years ago at least five orogenesis.

According to Countryaah, South America has significant mineral deposits. In the Andes, gold, silver, copper, tin, zinc, coal and nitrates are mined. The sediment basins have oil and gas deposits as well as bauxite and kaolinite deposits. In the bedrock, e.g. band iron ore (BIF), gold and gemstones. Brazil was until 1840 the world’s largest diamond producer; then it became South Africa.

South America wildlife

South and Central America and the Caribbean make up the neotropic region comprising the lowlands of the Amazon, mountain forests and plateaus in the Andes, subtropical savannas, the Patagonian plains and the temperate part of the Andes with its moist coastal forests. In northern Chile and in Peru, there are coastal droughts. See Countryaah for all countries in Caribbean and Caribbean Sea.

Caribbean Sea

The wildlife of South America is far richer in species than that of Africa and Asia. There are 800 species of mammals, of which 90 are marsupials – one of many proofs that South America and Australia up to 50 million. years ago the supercontinent belonged to Gondwana. The land connection between South and North America has been interrupted several times; the current Panama Sea is only 2.5-3 million years old. During the continent’s isolation, many endemic species and groups evolved: sloths (including giant forms), armadillos, the four llamas, 50 monkey species (including marmosets, tamarins, and true western monkeys such as howler monkeys), many rodents (including guinea pigs, and the world’s largest rodent, capybara or river pig) and five cat species (including jaguar and puma). In the rivers live two species of river dolphins and two species of manatees (manatees).

2,900 of the world’s 9,000 bird species live in South America, and the bird fauna is locally very rich in species; in the Peruvian National Park Manu, for example, 450 species have been seen or heard in a single day. The tropical mountain forest contains 2,000 bird species, such as anthills, which follow the army ants, the red Peruvian rock rooster, beaked toucans, nectar-drinking hummingbirds, the quetzal and macaw parrots. Higher up is the duck condor, which has a wingspan of 3 m and feeds on carrion. In the forests, the impressive harpy eagle catches monkeys and sloths, and in open areas, ostrich-like nandus are found. The strange, leaf-eating hoatzin, found in the Amazon, are hatched with claws on the wings. In the breeding grounds of seabirds off the coast of Peru and Chile, mountains are built up of excrement (guano), which was previously used as fertilizer.

The world’s largest snake, the anaconda, lives up to 10 m in the Amazon River and weighs 500 kg. Coral snakes, boas snakes and caimans (a group of crocodiles) are widespread. The Amazon also has 1,700 of South America’s 2,700 species of freshwater fish, such as pirate fish, electric eel and the up to 3 m long arapaima. The South American insect fauna is by far the richest in the world, and it is not yet known how many species there are; some researchers estimate the number of species to be up to 40 million, a large part of which are beetles. See also Galápagos, giant sloths and shield animals.

South America – Climate

South America extends from the tropical climate zone around the equator through the subtropical zone to the temperate climate zone of the southern regions.

The precipitation pattern is characterized by the high-pressure patterns of the global flow pattern in the North and South Atlantic, where the NE and SE passages bring precipitation inland, respectively, resulting in annual precipitation between 100 and 200 cm in most of South America. However, the whole of Argentina and northern Chile gets less than 100 cm, while the western part of the Amazon and the coastal signs to the NE get more than 200 cm. The reason is the precipitation that occurs in connection with the rising air masses of the intertropical convergence zone. For example, Paramaribo on the north coast has an annual rainfall of 230 cm. Southern winds along the west coast of the continent from the high pressure area in the South Pacific are dry, resulting in precipitation below 25 cm in certain areas along the coast and in the Andes.

The boundary line between tropical and subtropical climates, which theoretically should have an east-west course, will have a north-south course in the northwestern parts of South America due to the location of the Andes Mountains along the Pacific coast.