South America

South America,

fourth largest continent (2015 est. pop. 416,436,000), c.6,880,000 sq mi (17,819,000 sq km), the southern of the two continents of the Western Hemisphere. It is divided politically into 12 independent countries—ArgentinaArgentina
, officially Argentine Republic, republic (2015 est. pop. 43,418,000), 1,072,157 sq mi (2,776,889 sq km), S South America. Argentina is bordered by Chile on the west, Bolivia and Paraguay on the north, Brazil and Uruguay on the northeast, and the Atlantic Ocean on the
..... Click the link for more information. , BoliviaBolivia
, officially Plurinational State of Bolivia, republic (2015 est. pop. 10,725,000), 424,162 sq mi (1,098,581 sq km), W South America. One of the two inland countries of South America, Bolivia is shut in from the Pacific in the W by Chile and Peru; in the E and N it
..... Click the link for more information. , BrazilBrazil
, Port. Brasil, officially Federative Republic of Brazil, republic (2015 est. pop. 205,962,000), 3,286,470 sq mi (8,511,965 sq km), E South America. By far the largest of the Latin American countries, Brazil occupies nearly half the continent of South America,
..... Click the link for more information. , ChileChile
, officially Republic of Chile, republic (2015 est. pop. 17,763,000), 292,256 sq mi (756,945 sq km), S South America, west of the continental divide of the Andes Mts.
..... Click the link for more information. , ColombiaColombia
, officially Republic of Colombia, republic (2015 est. pop. 48,229,000), 439,735 sq mi (1,138,914 sq km), NW South America. Bogotá is the capital and largest city.
..... Click the link for more information. , EcuadorEcuador
[Span., = equator], officially Republic of Ecuador, republic (2015 est. pop. 16,144,000), 109,483 sq mi (283,561 sq km), W South America. Ecuador is bounded on the north by Colombia, on the south and east by Peru, and on the west by the Pacific Ocean.
..... Click the link for more information. , GuyanaGuyana
, officially Co-operative Republic of Guyana, republic (2015 est. pop. 769,000), 83,000 sq mi (214,969 sq km), NE South America. It is bordered on the N by the Atlantic Ocean, on the E by Suriname, on the S and W by Brazil, and on the W by Venezuela.
..... Click the link for more information. , ParaguayParaguay
, officially Republic of Paraguay, republic (2015 est. pop. 6,639,000), 157,047 sq mi (406,752 sq km), S central South America. Paraguay is enclosed by Bolivia on the north and west, Brazil on the east, and Argentina on the south and west; Bolivia and Paraguay are the
..... Click the link for more information. , PeruPeru
, Span. Perú , officially Republic of Peru, republic (2015 est. pop. 31,377,000), 496,220 sq mi (1,285,210 sq km), W South America. It borders on the Pacific Ocean in the west, on Ecuador and Colombia in the north, on Brazil and Bolivia in the east, and on
..... Click the link for more information. , SurinameSuriname
, officially Republic of Suriname, republic (2015 est. pop. 553,000), 63,037 sq mi (163,266 sq km), NE South America, on the Atlantic Ocean. Part of the Guiana region, it is separated from Brazil on the south by the Tumuc-Humac Mts.
..... Click the link for more information. , UruguayUruguay
, officially Oriental Republic of Uruguay, republic (2015 est. pop. 3,432,000), 68,536 sq mi (177,508 sq km), SE South America. The second smallest country (after Suriname) in South America, Uruguay extends from a short Atlantic coastline along the north bank of the
..... Click the link for more information. , and VenezuelaVenezuela
, officially the Bolivarian Republic of Venezuela, republic (2015 est. pop. 29,275,000), 352,143 sq mi (912,050 sq km), N South America. Venezuela has a coastline 1,750 mi (2,816 km) long on the Caribbean Sea in the north.
..... Click the link for more information. —and the overseas department of French GuianaFrench Guiana
, Fr. La Guyane française, officially Department of Guiana, French overseas department (2015 est. pop. 269,000), 35,135 sq mi (91,000 sq km), NE South America, on the Atlantic Ocean.
..... Click the link for more information. . The continent extends c.4,750 mi (7,640 km) from Punta Gallinas, Colombia, in the north to Cape Horn, Chile, in the south. At its broadest point, near where it is crossed by the equator, the continent extends c.3,300 mi (5,300 km) from east to west. South America is connected to North America by the Isthmus of Panama; it is washed on the N by the Caribbean Sea, on the E by the Atlantic Ocean, and on the W by the Pacific Ocean.

Topography and Geology

Topographically the continent is divided into three sections—the South American cordillera, the interior lowlands, and the continental shield. The continental shield, in the east, which is separated into two unequal sections (the Guiana Highlands and the Brazilian Highlands) by the Amazon geosyncline, contains the continent's oldest rocks. Geologic studies in South America have supported the theory of continental drift and have shown that until 135 million years ago South America was joined to Africa; a Brazil-Gabon link has been established on the basis of tectonic matching. Extending down the middle of the continent is a series of lowlands running southward from the llanos of the north, through the selva of the great Amazon basin and the Gran Chaco, to the Pampa of Argentina.

Paralleling the Pacific shore is the great cordillera composed of the Andes ranges and high intermontane valleys and plateaus. The Andes rise to numerous snowcapped peaks; Mt. Aconcagua (22,835 ft/6,960 m) in Argentina is the highest point in the Western Hemisphere. The Andes region is seismically active and prone to earthquakes. Volcanoes are present but mostly inactive. Patagonia, a windy, semiarid plateau region, lies to the E of the Andes in S Argentina. On the Pacific coast, the land between the Andes and the sea widens northward from the islands of S Chile. In N Chile lies the barren Atacama Desert.

There are few good natural harbors along the South American coast. The continent's great river systems empty into the Atlantic Ocean and the Caribbean Sea; from north to south they are the Magdalena, Orinoco, Amazon, and Paraguay-Paraná systems. Only short streams flow into the Pacific Ocean. Excluding Lake Maracaibo, which is actually an arm of the Caribbean Sea, Lake Titicaca, on the Peru-Bolivia border, is the largest of the continent's lakes. South America embraces every climatic zone—tropical rainy, desert, high alpine—and vegetation varies accordingly.

People

Native peoples constitute a significant portion of the continent's Andean population, especially in Bolivia, Ecuador, Peru, and Paraguay. Elsewhere in South America the population is generally mestizo, although Chile, Argentina, Uruguay, and S Brazil have primarily European populations. There are sizable populations of African descent in NE Brazil, French Guiana, Suriname, Guyana, Venezuela, and Colombia. Immigration since 1800 has brought European, Middle Eastern, and Asian (especially Japanese) peoples to the continent, particularly to Argentina and Brazil.

With the exception of Brazil and Ecuador, the national capitals have the largest populations and are the economic, cultural, and political centers of the countries. Since World War II, the urban population has rapidly expanded. São Paulo, Brazil, whose population is nearly 10,000,000, is the largest city of South America and one of the fastest growing cities of its size in the world. Squatter settlements have multiplied around urban areas as the poor and unskilled flock to the cities; widespread unemployment is common. Outside the cities the population density of the continent is very low, with vast portions of the interior virtually uninhabited; most of the people live within 200 mi (320 km) of the coast.

Economy

Beginning in the 17th cent., the exploitation of the continent's resources and the development of its industries were the result of foreign investment and initiative, especially that of Spain, Great Britain, and the United States, but since World War II the nations of South America have sought greater economic independence. An increasing number of South American industrial centers have developed heavy industries to supplement the light industries on which they had previously concentrated.

An early obstacle to industrial growth in South America was the scarcity of coal. The continent has therefore relied on its petroleum reserves, most notably in Venezuela and also in Argentina, Colombia, Chile, Peru, and Ecuador, as a source of fuel. South Americans also have gradually developed their natural-gas reserves; hydroelectric plants produce most of the continent's electricity. Iron-ore deposits are plentiful in the Guiana and Brazilian highlands, and copper is abundant in the central Andes mountain region of Chile and Peru. Other important mineral resources include tin in Bolivia, manganese and gold in Brazil, and bauxite in Guyana and Suriname.

Subsistence farming is widespread, with about 30% of the people working about 15% of the land. Dense forests, steep slopes, and unfavorable climatic conditions, along with crude agricultural methods, limit the amount of cultivable land. Commercial agriculture, especially of the plantation type, fares better in terms of production because of the large scale and the opportunity to use modern, mechanized methods. Among the agricultural exports are coffee, bananas, sugarcane, tobacco, and grains. Meat is also an important export. In the interior, hunting and gathering of forest products are the chief economic activities of the indigenous peoples. Fishing is also a central industry. In the more accessible areas, forest products are removed for export.

Outline of Modern History

European exploration and penetration of South America started at the beginning of the 16th cent. Under the Treaty of Tordesillas, Portugal claimed what is now Brazil, and Spanish claims were established throughout the rest of the continent with the exception of Guyana, Suriname, and French Guiana. An Iberian culture and Roman Catholicism were early New World transplants—as were coffee, sugarcane, and wheat. The subjugation of the indigenous civilizations was a ruthless accompaniment to settlement efforts, particularly those of Spain. The IncaInca
, pre-Columbian empire, W South America. The name Inca may specifically refer to the emperor, but is generally used to mean the empire or the people. Extent and Organization of the Empire
..... Click the link for more information. Empire, centered at Cuzco, Peru, was conquered (1531–35) by Francisco Pizarro; other native cultures quickly declined or retreated in the face of conquest, conversion attempts, and subjugation. In some areas of the continent, such as the Amazonian region, large population declines resulted from the spread of European diseases in advance of significant European contact. Spain and Portugal maintained their colonies in South America until the first quarter of the 19th cent., when successful revolutions resulted in the creation of independent states.

The liberated countries generally struggled with political instability, with revolutions and military dictatorships common and economic development hindered. Between 1820 and 1920, the continent received almost 6 million immigrants, nearly all from Europe. Guyana gained independence from Great Britain in 1966 and Suriname from the Netherlands in 1975. French Guiana is an overseas department of France.

Beginning in the 1970s, road building and the clearing of land led to the destruction of large areas of the Amazonian rain forests. International pressure and changes in government policy, especially in Brazil, resulted in a decrease in the deforestation rate since the late 1980s, although burning and illegal logging continue. Efforts to combat the illegal drug trade have been largely ineffective. Peru is one of the world's largest growers of coca leaves, and Colombia is a center for the drug trade.

Economic problems and social inequality have led to considerable unrest and political instability. Many indigenous peoples, angered by centuries of domination by a primarily European-descended upper class, have demanded a more equal distribution of land and power. Despite the increasing industrialization of some countries, notably Brazil, Venezuela, and Argentina, and the widespread introduction of free-market reforms in the 1990s, high inflation and huge foreign debt continued to be major problems for many South American countries. Such economic problems led to a rise in populist political parties and movements in the region in the early 21st cent., most notably in Venezuela and Bolivia.

See also Americas, antiquity and prehistory of theAmericas, antiquity and prehistory of the,
study of the origins of the aboriginal peoples of the Americas. Archaeologists believe humans had entered and occupied much of the Americas by the end of the Pleistocene epoch, but the date of their original entry into the Americas is
..... Click the link for more information. ; Natives, South AmericanNatives, South American,
aboriginal peoples of South America. In the land mass extending from the Isthmus of Panama to Tierra del Fuego, Native American civilizations developed long before the coming of the European.
..... Click the link for more information. .

Bibliography

See C. H. Haring, The Spanish Empire in America (1947, repr. 1963); K. E. Webb, Geography of Latin America (1972); G. Philip, The Military in South American Politics (1985); J. D. Hill, ed., Rethinking History and Myth: Indigenous South American Perspectives on the Past (1988); G. P. Atkins, ed., South America into the 1990s (1988); S. Bunker, Underdeveloping the Amazon (1988); A. Daniels, Coups and Cocaine: Journeys in South America (1988); A. Cullison, The South Americans (1990).

South America

South America is the southern continent of the western hemisphere, situated between 12°28’ N lat. (Point Gallinas on the Guajira Peninsula) and 53°54’ S lat. (Cape Froward on the Brunswick Peninsula) and between 34°47’ W long. (Cabo Branco) and 81°20’ W. long. (Pariñas Point). It is bounded by the Caribbean Sea on the north, the Atlantic Ocean in the east, the Strait of Magellan in the south, and the Pacific Ocean in the west. It is linked by the narrow Isthmus of Panama with Central and North America. The continent has an area of 17.65 million sq km (18.28 million sq km including islands). Among the islands that are part of South America are the Leeward Islands and Trinidad, the Falkland Islands, the Tierra del Fuego archipelago (Cape Horn, the southernmost tip of South America, at 55°59’ S lat., is located on an island in the south of the archipelago), the islands of southern Chile, and the Galápagos Islands.

The coastline of South America is weakly indented except in the southwest, where it is deeply cut by fjords. A number of large inlets cut deep into the land, including the Gulf of Guayaquil in the west, the Gulf of Venezuela and Lake Maracaibo in the north, and the Río de La Plata Estuary in the southeast. With the exception of the southwest, the Pacific coast has regular, straight, abraded, and aggraded coastlines, which are primarily rocky in Peru. The Atlantic coast is also relatively straight but lower than the Pacific coast. From Guanabara Bay south to 30° S lat., the coastline is moderately dissected and has convenient ingressive bays; open crescent-shaped bays are typical of the Patagonian coast.

The plains and high plateau topography of the non-Andean craton of the eastern part of South America is clearly delineated from the mountainous Andean western part, which corresponds to a mobile orogenic belt. Uplifts of the South American (Brazilian) Platform are represented by the Guiana, Brazilian, and Patagonian highlands, while the troughs are represented by various lowlands and plains, including the Orinoco Llanos, the Amazon Basin, the Beni-Mamoré plains, the Gran Chaco, the Mesopota-mian Plateau (a lowland between the Paraná and Uruguay rivers), and the Pampas. The plateaus are bounded in the east by narrow, discontinuous strips of coastal plains. (See Figure 1.)

The Guiana Highlands rise toward the center, reaching their highest point at Mount Neblina (3,014 m). The Brazilian Highlands (Brazilian Plateau) rise from northwest to southeast, reaching their highest point at Pico da Bandeira (2,890 m). Patagonia rises from east to west, reaching an elevation of 2,200 m. The topography of the Guiana and Brazilian highlands is dominated by gently rolling socle plains, with elevations of up to 1,500–1,700 m; the plains are interspersed with residual dome-shaped peaks and ridges, such as the Serra do Espinhaço, and tablelands, primarily sandstone tablelands called chapadas (Auyán-Tepuí and Roraima). The eastern margin of the Brazilian Highlands is broken up into individual massifs, such as the Serra da Mantiqueira, which have the characteristic “sugar loaf” formations, such as Sugar Loaf Mountain (Pao de Acucar) in Rio de Janiero. The troughs and basins of the Brazilian Highlands are expressed in the topography by stratified monoclinal plains with uplifted cuesta margins, aggradation plains (the basin of the Sāo Francisco River), and lava plateaus (the middle course of the Paraná River). The topography of Patagonia predominantly comprises volcanic, terraced plateaus overlain by ancient moraines and glaciofluvial deposits. The plateaus are dissected by deep canyons, carved out by rivers originating in the Andes. Arid denudation forms are characteristic.

The Andean system of mountain ranges stretches for 9,000 km in the north and west. In Venezuela in the north and northeast there are two chains of the Caribbean Andes, which are deeply dissected by faults and river erosion. The primary, or meridional trending, system of the Andes (or the Cordillera de los Andes), which rises to a maximum elevation of 6,960 m at Mount Acona-gua, is higher in the west and is subdivided into the Northern, Central, and Southern Andes. The Northern Andes (to 5° S lat.) are characterized by the alternation of high block-folded ranges and deep basins. In Ecuador they consist of the Cordillera Oriental and the Cordillera Occidental, separated by a depression filled with the volcanic products from Chimborazo, Cotopaxi, and other volcanoes. In Colombia there are three main cordilleras—Oriental, Central, and Occidental—which are separated by the basins of the Magdalena and Cauca rivers. The volcanoes, such as Nevado del Huila, Nevado del Ruiz, and Puracé, are concentrated mainly in the Cordillera Central and the southern part of the Cordillera Occidental. Ancient lake plateaus, situated at elevations of 2,000–3,000 m, are characteristic of the central part of the Cordillera Oriental. The largest lowlands west of the Andes, the Caribbean and Pacific lowlands, are located in the north and west.

The Central Andes (to 27°−28° S lat.) are much broader and more monolithic than the Northern Andes. They are characterized by high interior plateaus, uplifted to elevations of 3,800–4,800 m and surrounded by marginal mountain ranges. The highest mountains have considerable glaciation. The southern part, called the Central Highlands, is the broadest segment of the Andes, reaching a width of 750 km; its principal element is the Puna de Atacama, a high plateau, with the ancient Altiplano lake plateau in the southwest and a series of block ranges in the east and south. The Puna is bordered in the east by the Cordillera Real and in the west by the volcanic Cordillera Occidental (another volcanic region of the Andes, with the volcanoes El Misti, Llullaillaco, and Sajama), a longitudinal tectonic depression (with the Atacama Desert), and the Coastal Cordillera (or Coastal Range).

In the northern part of the Southern Andes (to 41°30’ S lat.), the outstanding features of the relief are the paired Cordillera Principal (Mount Aconcagua is in the Cordillera Frontal), which borders on the massifs of the Precordillera in the east; the Longitudinal Valley of Chile; and the Coastal Cordillera. Between 33° and 52° S lat., there is still another volcanic region, with a large number of active volcanoes to the west of the Cordillera Principal and extinct volcanoes to the east. In the southernmost part of the Andes, known as the Patagonian Andes, the Coastal Cordillera becomes an island archipelago and the Longitudinal Valley becomes a system of straits, while the submerged glacial valleys of the abruptly descending Patagonian Cordillera form fjords. Glacial topography predominates. Glaciers in South America now occupy an area of 25,000 sq km, more than 21,000 of which are in the Southern Andes. There are also glaciers in the Cordillera Occidental, between 9° and 11° S lat., and on Tierra del Fuego.

E. N. LUKASHOVA

Geological structure and minerals. The continent of South America consists of two principal structural units—the South American (Brazilian) Craton, in the central and eastern parts, and the folded mountain belt of the Andes, which frames the continent in the north, west, and south.

The basement of the South American Craton consists of blocks of different ages that consolidated between the Archean and Early Paleozoic eras. The largest basement outcroppings are the Guiana, Central Brazilian, and Eastern Brazilian shields. The first two are almost entirely composed of deeply metamorphosed and intensively deformed Archean and Lower Proterozoic rocks (gneisses, schists, and granites) and Middle or Upper Proterozoic rapakivi-type granites. The Eastern Brazilian Shield consists of individual Early Precambrian blocks, such as the Sāo Francisco Massif, which are separated from one another and bounded by Late Proterozoic geosynclinal folded systems. The ancient basement was intruded by numerous granitoids and associated pegmatites during the Cambrian and Ordovician periods. Remnants of the ancient mantle, composed of red detrital strata and basaltic sheets with gabbro-diabase dikes and sills, have been preserved in the Guiana and Central Brazilian shields, forming watersheds; a younger mantle, consisting of rocks of Middle and Late Paleozoic and Mesozoic ages, fills the depressions of the platform. In the Late Carboniferous and Early Permian periods, the area south of the Amazon was covered by a continental ice sheet. A warming of the climate led to the replacement of glacial deposits (tillites) first by coal-bearing beds (Lower Permian) and then by arid strata, primarily sandstone strata (Upper Permian through Cretaceous).

The broad Amazon Basin formed in the Late Precambrian and Early Paleozoic eras along a major fault zone between the Guiana and Central Brazilian shields. Another zone of east-west-trending depressions separates the Eastern Brazilian Shield from the Western Brazilian Shield. Its central element, the Sāo Francisco Basin, was superimposed on the ancient Sāo Francisco Massif and developed primarily in the Late Precambrian era. The northern and southern basins—the Marañen (Parnaíba) and Paraná syneclises—formed during the Middle and Late Paleozoic and during the Mesozoic; in the Paraná Syneclise, basaltic sheets and sills and dikes of basic rocks (traps) developed extensively, mainly in the Early Cretaceous period. Numerous intrusions of ultrabasic and alkaline rocks, including alkaline granitoids, occurred in the Eastern Brazilian Shield in the Late Cretaceous and Early Paleogene periods.

The southern part of the South American Craton—the Patagonian Shield—is distinguished by a younger basement, which includes the lowermost strata of the Paleozoic era. It is usually considered to be an independent structural unit consisting of two uplifts—the Northern Patagonian Massif and the Southern Patagonian Massif (Deseado and Santa Cruz)—and two troughs—Neuquén-San Matías and Chubut-San Jorge. The southernmost part of the craton passes into the Magallanes Foredeep of the Andes. A system of perioceanic downwarps associated with the formation of the ocean basin (beginning in the Cretaceous period) developed along the Atlantic coast of South America. Grabens and semigrabens are filled with continental, salt-bearing, and marine Cretaceous deposits. The Cenozoic era is represented by the coastal plain and shelf, sloping gently toward the ocean.

The folded mountain belt of the Andes consists of several sections, which differ considerably with respect to geological historical and structure. The coastal sierra in northern Venezuela, an east-west-trending range, is the southern branch of the Antillean Arc and formed primarily during the Mesozoic era (the Early Jurassic) and the Cenozoic era. The Northern Andes proper (western Venezuela, Colombia, and Ecuador) are represented by a cluster of ranges that break up into branches in the north and that correspond to large, young anticlinoriums. The Cordillera Oriental of Colombia, as well as the Sierra Nevada de Mérida, the Sierra de Perijá, and the Sierra Nevada de Santa Marta, formed on a Precambrian granite-metamorphic basement overlain by epicontinental Paleozoic and Mesozoic strata. The Cordillera Central of Colombia and the Cordillera Oriental of Ecuador are composed primarily of metamorphosed Paleozoic rocks, which had undergone folding and were intruded by granites in the Late Paleozoic era. The uplifts are separated by inter-montane troughs (Maracaibo, Magdalena, and Cauca-Patfa) filled with Cenozoic molasses.

The Central Andes are characterized by a northwesterly strike, which changes to meridional at the latitude of the cities of Arica (Chile) and Santa Cruz (Bolivia), and it is here that the Andes reach their greatest width. The eastern part is composed primarily of intensively folded rocks of Cambrian through Devonian ages, which are unconformably overlain by Late Paleozoic volcanic molasses. The Altiplano graben, which is filled primarily with a thick, primarily continental, Cretaceous layer, is situated in the middle part of the Central Andes. Stretching to the west is a band of Jurassic and Cretaceous deposits, with strata of andesites (porphyrites) and large Cretaceous and Paleogene granitoid batholiths (Cordillera Occidental of Peru and Cordillera Principal of Chile and Argentina). The Coastal Cordillera, which is composed of a Late Precambrian and Early and Middle Paleozoic metamorphic stratum, extends, with breaks, along the coast of Peru and Chile. In the extreme south the Andes turn southeastward, becoming an island arc that frames the Scotia Sea; here, they are composed of ophiolites overlain by a Jurassic and Lower Cretaceous porphyrite series and by Upper Cretaceous and Lower Paleogene flysch. This entire complex of rocks is thrust over the molasses of the Magallanes Foredeep. During the Cenozoic, the Andes were subjected to intensive volcanic activity, which continues until the present in three areas: Ecuador, the border region of Peru, Chile, and Bolivia, and the central part of Chile. Earthquakes are common, and some in Peru and Chile are highly destructive. In the east, the Andes are characterized by a discontinuous strip of foredeeps—the Subandean Foreland—filled chiefly with thick Cenozoic molasses.

South America is rich in a variety of mineral resources. Major deposits of iron ore are present in the Late Precambrian strata of Venezuela (the Orinoco River basin) and Brazil (Minas Gerais), and very rich deposits of porphyry copper ores occur in the granitoid batholiths of the Central Andes. Deposits of ores of rare elements are linked to the ultrabasic alkaline intrusions in the eastern part of Brazil. Deposits of tin, antimony, silver, and other minerals have been found in the young volcanic and subvolcanic bodies in Bolivia. The foredeeps and intermontane troughs of the Andes contain deposits of petroleum and gas throughout their entire length; the deposits in Venezuela are particularly rich. There are deposits of coal: hard coal in Upper Paleozoic strata and brown coal in Cenozoic strata. Deposits of bauxite occur in the young weathering crust, especially in Guyana and Surinam.

V. E. KHAIN

Climate. South America’s position primarily in the low latitudes results in a large influx of solar heat. The radiation balance almost everywhere is 60–90 kilocalories/cm² a year, except in Patagonia, where it decreases to 30–40 kilocalories/cm². North of the tropic of Capricorn, the average monthly temperature fluctuates primarily between 20° and 28°C (with a maximum of 49°C in Gran Chaco), dropping in the summer (January) to 10°C in Patagonia and in the winter (July) to 12°–16°C on the Brazilian Highlands, 6°–10°C in the Pampas, and 1°C in the extreme south (the lowest temperatures are around –30°C, which occur on the high plateaus and in the south). Equatorial and trade-wind-monsoon circulation predominates, characterized by an easterly transfer of air masses; consequently, the eastern plains and plateaus and the eastern slopes of the Andes are influenced primarily by oceanic air from the Atlantic, which, because of the Andean barrier, never reaches the Pacific west. A westerly transfer predominates in the southern part of the continent. The lack of orogenic obstacles within the continent is responsible for the meridional transfer. Altitudinal zonation of climate is clearly marked in the Andes.

South America spans six climatic belts: the equatorial, northern subequatorial, southern subequatorial, tropical, subtropical, and temperate belts. In the equatorial belt in the east (western part of the Amazon Basin and the adjacent slopes of the plateaus and the Andes), a low-pressure system is present year-round, linked with the intertropical zone of convergence of air masses and accompanied by abundant precipitation. In the west the equatorial belt is located to the north of the equator, in western Colombia. A consistently hot and humid climate characterizes the equatorial belt (see Table 1). In the Andes of southern Colombia, in Ecuador, and on the eastern slopes in Peru, equatorial air masses also predominate, and these regions have altitudinal zones of mountain equatorial climate, with precipitation and temperatures that are just as uniform (although they decrease with elevation) as on the plains. (See Table 1.)

The intertropical zone of convergence and the equatorial air masses (equatorial monsoon) shift to the subequatorial belt during the summer of the corresponding hemisphere, causing a rainy season. In the winter, by contrast, dry tropical (trade-wind) air masses predominate in the subequatorial belts. The western edge of the South Atlantic High also encompasses the eastern, elevated, margin of the Brazilian Highlands. Therefore, the subequatorial climate is characterized by humid summers and dry winters and by somewhat higher temperatures than the equatorial climate. A similar climate is found in the northern part of the continent: the Orinoco Llanos, the northern part of the Guiana Highlands, the northern and central parts of the Brazilian Highlands, the plains of Acre, Beni, and Mamoré, and western Ecuador. On the windward slopes of the plateaus and in the eastern part of the Amazon Basin, where the trade winds blow from the ocean, the dry season is very short, while on the lee slopes of the northeastern part of the Brazilian Highlands, it is very long.

In the tropical zone, the amount of precipitation that falls changes significantly from east to west. Arid conditions are characteristic of eastern Brazil, which is subjected to oceanic trade winds. In the heart of the continent (Gran Chaco), summer rains are linked primarily to the penetration of equatorial air from the north into a region of barometric minimum; in the winter, air masses from the south intrude, which although they warm up and dry out still cause sudden cooling as far as the Amazon Basin (called the friagens). The Puna of the Central Andes is almost entirely cut off from the easterly winds. In the north it has a high-mountain arid tropical climate, with summer precipitation; in the center and south it has a continental desert climate. The extreme western part of the continent, between 5° and 28° S lat., is constantly influenced by the eastern periphery of the South Pacific High, in which air masses settle and form trade-wind inversions. Its low position and stable stratification and the cooling of its lower layers are intensified by the cold Peru (Humboldt) Current; the trade winds blow from the colder latitudes in a direction parallel to the coast and the Andes. All these factors are responsible for the exceptional aridity of the western part of the tropical belt, and in some places no precipitation falls for years at a time. The coastal strip is characterized by heavy fogs and drizzle (garúa) in the winter and spring and by relatively low temperatures.

The subtropical belt in the east (the southern Brazilian Highlands, the Mesopotamian Region, and the eastern part of the Pampas) has a warm, perpetually humid climate. In the summer, monsoon-type Atlantic winds bring precipitation; during the rest of the year, rain comes from cyclones of migrating polar fronts. Strong southerly winds, called pamperos, are characteristic and cause frosts even in the tropics in the winter. The climate becomes increasingly arid as one moves westward, and precipitation (of a convective nature) falls only in the summer. The western part of the subtropical belt (central Chile) has a typical Mediterranean-type climate, with dry summers and wet winters, a climate similar to that on other continents. South of 38° S lat., the amount of precipitation increases rapidly and, influenced by westerly winds from the Pacific Ocean, it falls during the summer.

In the temperate belt, a westerly transfer of air masses predominates, which results in enormous amounts of precipitation falling on the windward, or western, slopes of the Andes but little seasonal temperature variation. Patagonia is located in the rain-shadow zone and has a semidesert climate, with strong southwesterly winds and sharp temperature fluctuations.

Table 1. Principal climatic indexes of South America (upper row, temperature; lower row, precipitation)
Belt	Observation point, coordinates	Station’s elevation (m)	Average monthly temperature (°C) and average monthly precipitation (mm)												Average annual precipitation (mm)
Belt	Observation point, coordinates	Station’s elevation (m)	Jan.	Feb.	Mar.	Apr.	May.	June.	July.	Aug.	Sept.	Oct.	Nov.	Dec.	Average annual precipitation (mm)
Equatorial	Taraquá 0°04’ N lat. 68°14’ W long.	105	25.2 320	25.3 268	25.3 326	25.2 422	24.9 429	24.5 350	24.1 315	24.7 250	25.3 237	25.4 215	25.4 247	25.2 275	3,654
	Bogotá 4°28’ N lat. 74W W long.	2,556	14.4 54	14.8 56	14.8 85	15.0 118	14.8 107	14.3 56	14.0 45	13.8 45	14.2 56	14.6 143	14.3 132	14.0 80	977
Subequatorial	San Fernando de Apure 7°54’ N lat. 67°25’ W long.	74	26.7 0.6	27.6 4	28.8 16	29.0 74	27.3 173	25.9 250	25.6 288	26.2 285	27.0 168	27.2 134	27.2 46	26.9 10	1,448
	Santarém 2°25’ S lat. 54°43’ W long.	72	25.8 180	25.5 275	25.5 348	25.6 362	25.6 294	25.4 174	25.4 112	26.2 50	26.7 39	27.0 46	26.9 83	26.5 123	2,086
	Goiânia 16°38’ S lat. 49°13’ W long.	747	22.8 234	23.0 210	22.8 198	22.2 110	20.4 30	18.9 9	18.8 10	21.2 3	23.2 36	23.6 143	23.0 237	22.7 271	1,491
	Remanso 9°41’ S lat. 42°04’ W long.	411	27.5 88	27.5 66	27.1 109	27.3 36	27.0 12	26.0 1	25.6 1	26.0 0	27.2 4	28.3 11	28.0 74	27.5 94	496
	Guayaquil 2°12’ S lat. 79°53’ W long.	6	25.5 188	26.0 211	26.4 248	26.3 184	25.6 56	24.4 14	23.5 6	23.2 0.4	23.8 0.1	24.0 2	24.6 1	25.4 16	926
	Cuzco 13°33’ S lat. 71°55’ W long.	3,225	12.8 160	12.2 137	12.4 93	12.3 44	11.3 10	10.4 6	10.2 3	11.2 5	12.4 23	13.3 46	13.6 65	13.6 105	697
Tropical	Santos 23°56’ S lat. 46°20’ W long.	2	25.2 248	25.3 320	24.8 248	22.8 203	20.8 158	19.3 120	18.5 91	19.0 113	19.7 145	20.9 176	22.2 158	23.9 204	2,184
	Rivadavia 24°10’ S lat. 62°54’ W long.	205	28.8 101	27.8 100	25.9 90	22.6 38	19.4 8	16.8 4	16.6 3	18.7 4	22.4 16	24.6 38	26.9 60	28.5 80	542
	Oruro 17°58’ S lat. 67°07’ W long.	3,706	12.7 86	11.9 69	11.9 34	10.3 9	6.9 3	4.3 1	4.1 1	5.9 7	8.6 13	11.3 16	12.4 20	12.6 36	295
	Antofagasta 23°42’ S lat. 70°24’ W long.	94	20.1 0	20.2 0	18.8 0	17.0 0,3	15.2 0	13.8 2	13.6 3	13.4 2	14.4 0.8	15.4 1	17.0 0.3	19.0 0	9
Subtropical	Montevideo 34°42’ S lat. 56°12’ W long.	22	11.4 83	12.1 78	13.5 101	15.5 104	15.9 93	16.7 88	18.7 70	17.7 87	17.1 82	15.9 76	12.9 83	11.3 74	1,019
	Santiago 33°27’ S lat. 70°42’ W long.	520	20.0 2	19.3 2	17.1 5	13.7 14	10.6 62	8.2 82	8.0 74	9.1 57	11.5 29	13.8 14	16.6 6	19.0 4	351
	Valdivia 39°48’ S lat. 73°14’ W long.	5	16.5 69	16.0 68	14.2 129	11.7 214	9.4 378	7.9 430	7.6 405	8.0 333	9.4 217	11.1 129	13.2 116	15.0 98	2,586
Temperate	Sarmiento 45°35’ S lat. 69°04’ W long.	268	17.7 7	16.8 9	14.4 12	10.8 12	6.8 21	3.8 17	3.6 17	5.3 14	8.0 10	11.5 7	14.0 9	16.0 7	142
	Puerto Aysén 45°24’ S lat. 72°42’ W long.	10	13.6 201	13.4 198	11.5 250	9.6 241	6.7 322	4.5 286	4.7 319	5.0 309	7.2 210	9.5 208	10.7 193	12.5 207	2,944

Rivers and lakes. The characteristics of South America’s topography and climate are responsible for the exceptional abundance of surface and subterranean waters, enormous runoff, and the largest river in the world, the Amazon, South America occupies 12 percent of the world’s land area but receives, on the average, about twice as much (1,643 mm) precipitation per unit area. The continent’s total river discharge accounts for 27 percent of the world’s total discharge, and the average depth of the runoff (58 cm) is twice the earth’s average value. The amount of runoff varies sharply in different parts of the continent, ranging from a few millimeters to hundreds of centimeters. The rivers are also distributed extremely unevenly between the two ocean basins; the Pacific receives 12 times less runoff than the Atlantic (the divide between them runs basically along the Andean ranges). Moreover, about 10 percent of South America is a region of internal drainage, which crosses the continent from the Gulf of Guayaquil through the Central Andean Highlands to the southern Pampas. Rivers that are fed by rain predominate; in the extreme south, rivers are also fed by snow and glaciers.

Annual runoff is greatest (150–400 cm, up to 90 percent of precipitation) in southern Chile, a result not only of the abundant precipitation but also of the steepness of the slopes, slow evaporation, and the presence of ice in the upper reaches of the rivers—all of which are responsible for summer high stages (which is also true of Patagonia’s ephemeral rivers). Underground waters account for not more than 20–25 percent of the flow of the southern Andean rivers. Runoff is just as high in western Colombia (reaching 800 cm in certain river basins). However, the rivers in the region are primarily fed by rain; the heavy rainfall causes summer and autumn flash floods, and subterranean runoff increases to 40 percent.

The runoff characteristics of the Amazon are similar, decreasing to 40–60 cm in its middle and southern courses. The regimes of the large rivers, like the regime of the Amazon itself, depend on the rainy season in the upper and middle reaches of the tributaries. On the margins of the Brazilian and Guiana highlands, which are well and more or less evenly watered, annual runoff is also 40–60 cm (up to 150 cm in some places), with underground runoff constituting 50 percent. The runoff decreases in the interior regions of the Brazilian Highlands to 5 cm in the northeast and becomes extremely uneven. Turbulent summer floods are followed by a sharp decrease in flow during the winter, with the shallow streams completely drying up. The runoff regime is similar on the plains of the subequatorial and tropical belts, where rivers are fed by rain (Orinoco Llanos, Beni-Ma-moré Plains, and Gran Chaco). The marked seasonality of precipitation results in variability in runoff (average runoff decreases from 50–80 to 15–20 cm) and river regimes: in the winter of the corresponding hemisphere, flow completely stops in some places and even large streams, such as the Bermejo and Salado, break up into stretches of water with saline water; in the summer, floods inundate vast areas. The flow of the Paraguay and Paraná rivers is regulated by the low-lying swamp and lake regions of the Pantanal and La Plata lowlands. The smallest runoff (3–5 mm) occurs in the tropical deserts of the western part of South America, where even meltwater from the high mountains accumulates in the foothill pediments and tectonic depressions, increasing the share of underground feeding of ephemeral rivers to 50 percent; only the Loa River has a year-round flow reaching the ocean.

Because of the large amount of precipitation brought from the Atlantic and the extensive plateaus sloping gently toward vast lowlands and plains that also collect runoff from the neighboring slopes of the Andes, a number of large river systems have developed in the non-Andean, or eastern, part of South America: the Amazon, the Orinoco, the Paraná with the Paraguay, and the Uruguay systems. The largest river system in the Andes is the Magdalena River, which flows along an elongated depression in the humid Northern Andes. For the most part, only the lowland rivers are suitable for navigation. The mountain rivers of the Andes and the plateaus, with abundant rapids and waterfalls (Angel Fall, 1,054 m; Kaieteur Falls, 226 m; and Iguacu Falls, 72 m), have enormous hydroelectric potential, as do the large streams of the constantly wet plains (more than 300 million kilowatts).

The large lakes, which are chiefly of glacial origin (terminal basins), are concentrated mainly in the Patagonian Andes (for example, Lakes Argentino and Buenos Aires) and in the southern part of central Chile (Lake Llanquihue). Lake Titicaca, a large lake situated at the highest elevation in the world, lies in the Central Andes, where there are also many residual lakes, such as Lake Poopó, and large solonchaks. The latter are also typical of the depressions between the ranges of the Sierras Pampeanas (Salinas Grandes and others). Large lagoons are located in the north (Lake Maracaibo) and the southeast (Lakes Patos and Mirim).

Soil and flora. The flora of most of South America is included in the Neotropical Region, while that of the southern part is included in the Antarctic Region.

In conformity with its geographic position in the low latitudes, the continent has predominantly evergreen and summer green forests, open woodlands, and scrub vegetation and is characterized by lateritic soil formations. The plant formations of the evergreen, primarily equatorial, rain forests are more widespread in South America than anywhere else on the earth. Such forests, called selvas, occupy almost the entire Amazon Lowland and the adjacent slopes of the plateaus and the Andes, as well as western Colombia and the eastern slopes of the Brazilian Highlands. They are distinguished by very rich and ancient floristic composition, considerable density, and the largest biomass growth (50–200 tons/hectare) and by the presence of many valuable plants. Typical plant families are Leguminosae, Myrtaceae, Meliaceae, Lauraceae, and Palmae. Lianas (Begoniaceae, Passi-floraceae, and other families) and epiphytes (primarily Orchida-ceae and Bromeliaceae) are abundant. The primary reserves of hard woods are concentrated in these forests, which are the probable place of origin of the cacao tree, the rubber-bearing hevea, and, probably, the papaya tree, the coconut plam, manioc, and sweet potato. The rain forest has red-yellow acidic ferralitic soils, as well as podzolized soils, with bog soils in the depressions. Alti-tudinal zonation is clearly expressed in the rain forests of the Andes. To elevations of 1,000–1,200 m (tierra caliente), the forests and soils are similar to the rain forests and soils of the plains. Tree ferns and bamboos predominate to elevations of 1,800–2,200 m (tierra templada), with many cinchona and coca trees. Cloud forests, composed of small trees and shrubs growing on mountain lateritic-humus soils, occur at elevations of 3,000–3,200 m (tierra fría). Above this are Alpine equatorial meadows, called páramos, consisting of frutescent grasses and arborescent flowering plants that grow year-round on mountain meadow soils, some of which are volcanic. In the eastern part of the Amazon Basin and at greater distances from the equator, where the dry season is longer, some deciduous trees appear in the rain forests. In the northern part of the Guiana Highlands and in the northern and eastern parts of the Brazilian Highlands, the rain forest is supplanted by deciduous-evergreen forests.

The subequatorial and tropical belts, with clearly expressed dry seasons, are dominated by savannas and open woodlands, with fringing forests in the river valleys. In the southern part of the Orinoco Llanos (where the savannas are also called llanos) and on the plains of Beni-Mamoré, Araguay, and Tocantins, these are humid, high-grass, primarily palm savannas and savanna forests growing on red ferralitic soils. In the central part of the Brazilian Highlands are savannas with small xerophilous trees (campos cerrados) growing on reddish chestnut soils. Similar xerophilous formations occur in the northern part of the continent. The arid stunted sparse forest known as the caatinga, consisting of thorny shrubs, cacti, and bottle-shaped trees (Chlorisia crispiflora) of the family Bombacaceae, occurs in the driest northeastern part of the Brazilian Highlands. Dry tropical forests and open woodlands grow on reddish chestnut soils on the plains of the Gran Chaco; the very valuable quebracho tree, a primary source of tannin, grows here.

In the subequatorial and tropical belts the lower parts of the eastern slopes of the Andes are characterized by deciduous-evergreen forests, the middle parts by evergreen forests, and the higher slopes by alpine cloud forests with some deciduous species. Above the forests in the Andes and on the high plateaus of Peru and northern Bolivia are high-mountain steppes known as jaleas. The southern plateaus of the Central Andes and the western slopes of the tropical belt have semidesert and desert soils and vegetation. In the winter, during the garúa, the loma formation of ephemeral annuals and tuberous-rooted perennials develops in the coastal deserts at elevations of 300–900 m.

In the subtropical zone in western South America, the semideserts are supplanted by Mediterranean-type dry-summer hard-leaved forests and shrubs (espinal and matorral) growing on chestnut soils. South of 37°–38° S lat., they are replaced by mixed evergreen rain forests, with subantarctic beeches (Nothofagus), magnolias, laurels, and other leafy trees intermixed with conifers (the pine Araucaria imbricata, podocarpus, Libocedrus, and Fitzroya) and many lianas, bamboos, epiphytes, and ferns; the soils are brown forest soils. Mixed evergreen rain forests cover the eastern slopes of the Andes to 42° S lat. There are Alpine meadows in the high mountains. East of the Andes, in northwestern Argentina, scrub semidesert with sierozems and stretches of desert predominate. As the amount of moisture increases toward the east, the semideserts and deserts are replaced first by dry scrub steppes with gray-chestnut soils and then by grass-forb steppes (pampas) with reddish black soils, which are also common in southern Uruguay. Savannas with mesophilic shrub or treeless savannas (campos limpos) predominate on the plains of Uruguay and in the extreme southeast of Brazil. Parklike forests and chernozem-like soils predominate in the southern part of the Mesopotamian Region. The subtropical evergreen rain forests known as pinheirais, consisting primarily of Brazilian araucaria and the Paraguayan holly yerba maté growing on typical red-earth soils, occupy the elevated southern margin of the Brazilian Highlands.

The vegetation and soils of the western and eastern parts of the temperate belt are noted for their vivid contrasts. The islands and wet western slopes of the Patagonian Andes are covered by southern-type forests, primarily evergreens and deciduous subantarctic beeches intermixed with conifers, growing on brown, partially podzolized forest soils. The eastern slopes of the Andes are characterized by coniferous-deciduous forests, while leeward Patagonia is characterized by semidesert brown soils and vegetation consisting of sparse caespitose grasses and cushiony dense umbellifers; steppes with chestnut soils appear only in the submontane depression and in the northern part of Tierra del Fuego. Cryophilic meadows and sphagnum bogs occur in the extreme southeast.

Subtropical and tropical swamps cover enormous areas in the basin of the upper Paraguay River and along the middle course, in the Mesopotamian Region, and in lowlands where many rivers merge. The northwestern and eastern coasts of the continent (to 27° S lat.) are frequently lined by mangrove thickets.

Much of the natural vegetation in certain parts of the continent has not survived, including the inter-Andean plateaus and interior slopes of the Northern Andes, the Longitudinal Valley of central Chile, the eastern slopes of the Brazilian Highlands, and, especially, the Pampas, which has been entirely put to crops or use as pastureland. Soil erosion has developed most extensively in these regions. In recent years the Amazon rain forest has been subjected to excessive logging.

Fauna. Because of the characteristics of paleogeographic development, not just the flora but also the fauna of South America is so unique that the continent, together with the West Indies and Central America, is singled out as an independent realm, the Neogaean, with one region, the Neotropical Region. The latter region has two subregions in South America, the Guiana-Brazilian Subregion, which encompasses most of the northern part of the continent, and the Patagonia-Andean, or Chilean, Subregion, which includes the southern plains and the Andes as far as Ecuador.

A number of endemic species are characteristic of the Neotropical Region. Mammals include edentates (the families Bradypodidae, Myrmecophagidae, and Dasypodidae), platyr-rhine monkeys, a number of rodent families, vampire bats (order Chiroptera), and llamas. Other animals include caenolestids (marsupials), several orders of birds, and various reptiles, amphibians, fish, and invertebrates. There are only a few even-toed ungulates, almost no insectivores, and no catarrhine monkeys. The existence of marsupials, the boa constrictor, the coral snake, and dipnoan fish attest to ancient ties between South America and Madagascar and Australia.

The equatorial and tropical rain forests have the richest fauna. Many animals with prehensile tails live in the trees, including cebids (howling monkeys, capuchins, uakaris, spider monkeys), pygmy and collared anteaters, opossums, prehensile-tailed porcupines, kinkajous, and sloths. Small monkeys of the family Callithricidae (marmosets) are common. The jaguar and ocelot, members of the family Felidae, are good tree climbers. There are numerous chiropterans. The bird fauna is very rich. A number of birds are endemic, including toucans, hoatzins, curassows, black vultures (urubus), macaws, and Amazona parrots. Hummingbirds abound (there are a total of 319 species in South America). Reptiles include snakes (constrictors and the poisonous bushmasters, or surucucu, cobras, and Bothrops jararaca), lizards (iguanas, skinks, and heloderms), and arboreal amphibians.

Insects are numerous. The butterfly fauna of South America is one of the richest in the world. The continent has 100,000 species of beetles, including the luminous cucujo and the long-horned beetle Titanus giganteus, which reaches a length of 15 cm. Several species of ants are linked with trees, for example, the leaf-cutting ants. A typical arachnid is the bird spider. Terrestrial animals include the giant armadillo and the giant anteater, peccaries, tapirs, the white-nosed coati, the bush dog, and various rodents, including the capybara, the largest rodent in the world, and guinea pigs.

The rivers and lakes are inhabited by manatees, river dolphins of the genus Inia, anacondas, (which are endemic), caymans, dipnoan South American lungfish, the giant pirarucu, carnivorous piranhas, and electric eels. There are about 2,000 fish species, which constitute one-third of the world’s total freshwater fauna.

The dominant terrestrial animals in the subequatorial and tropical savannas and open woodlands are armadillos and brockets, which are small deer, and various predators, including the puma, savanna fox, and maned wolf (in the north). Other animals include rodents and rheas. In the steppes and semideserts of the south the most characteristic animals are various endemic rodents (guinea pigs, coypus, pacas, tuco-tucos, maras, vizcachas, and agoutis) and flightless (running) birds (screamers, tinamous, common rheas, and Darwin’s rheas). There are also condors. Predators are represented by the pampas cat, the culpeo, Merhitis patagonica, and many pumas. The pampas deer represents the even-toed ungulates. The guanaco, a member of the family Camelidae, is almost extinct. Armadillos are common. The small pudu and guemal deer, the culpeo, the colocolo cat (Felis colocola), and the uellin otter (Lutra provocax) are especially typical of the forests of the Southern Andes; the relict spectacled bear and the chinchilla live in the high mountains of the Central Andes. The llama and alpaca, domesticated species of the genus Lama, are of great economic importance in the Andes; remnants of the herds of wild species, the guanaco and vicuña, are preserved. The coypu has been introduced in the USSR.

Preserves. South America has about 100 national parks and preserves, primarily to protect valuable forests and animal species threatened with extinction and to preserve picturesque recreational areas. They constitute about 1 percent of South America’s total area. Peru has the largest area of preserves, about 6 million hectares, while Argentina has 2.6 million and Venezuela has about 2 million. The best-known national parks are Nahuel Huapi and Los Glaciares in Argentina, Itatiaia and Iguacu in Brazil, and Los Paraguas in Chile.

Natural regions. Because of the sharp differences in its macrorelief, South America can be subdivided into two distinct areas: the non-Andean plains and plateaus of the east, characterized by horizontal natural zonation, and the mountainous Andean west, characterized by altitudinal zonation and flora and fauna specific to each natural belt.

There are numerous natural regions in the non-Andean east. The Orinoco Llanos, a plain in the subequatorial belt, is characterized by the alternation of a summer wet season and a winter dry season, which determines the seasonal rhythms of all natural processes.

The Amazon Basin is a low-lying plain in the equatorial belt, with a dense network of large rivers and a vast cover of evergreen rain forests—selvas.

The Guiana Highlands are dominated by socle-type denudation plains, with crystalline ranges and sandstone tablelands. The region is characterized by a hot and, in most places, continuously moist climate and by large rushing rivers and evergreen rain forests (those in the north are characterized by high humidity only part of the year).

The Brazilian Highlands have uplifted socle-type plains in the northwest and high massifs in the east, separated by a belt of depressions with sedimentary and lava plains. The rivers are fast-flowing and are characterized by seasonal regimes. In the sub-equatorial northwest and the tropical east, there are rain forests, both those with high humidity year-round and those with high humidity only part of the year. In the central part of the Brazilian Highlands is a belt of brush savannas, called campos cerrados, and in the arid northeast lies the arid stunted sparse forest known as the caatinga. The continuously wet southeastern part has evergreen coniferous-deciduous forests and the largely treeless savannas called campos limpos.

South America’s interior plains are aggradation plains occupying the tectonic trough between the Brazilian Highlands and the Andes extending parallel to the Paraguay and Paraná rivers from 10° to 39° S lat. They are characterized by the alternation of zonal types of landscape, ranging from subequatorial savanna forests and savannas in the north (the Beni-Mamoré plains) to the tropical open woodlands of the central part (Gran Chaco) to the subtropical savannas and forest-steppe and steppe landscapes of the south (Mesopotamian Region and the Pampas). The ephemeral rivers of the Gran Chaco and the vast areas of internal drainage in the Pampas are noteworthy. The amount of precipitation received by the Pampas decreases from east to west, and there is a corresponding change in zonal types, from pampas and brush steppes to semideserts.

The Sierras Pampeanas and Precordillera are a region of block-folded massifs alternating with subtropical climates, internal drainage, xerophilous forests on the windward, or eastern, slopes, dry scrub forests on the lee, western slopes, and semi-deserts with solonchaks in the basins.

Patagonia is a high plateau, with a temperate continental climate. It lies in the rain-shadow zone of the Andes and has ephemeral rivers and semidesert vegetation and soil.

Numerous natural regions are identified within the Andean west. The Caribbean Andes are strongly dissected ranges, with a subequatorial wet-summer type of climate, short streams that often dry up in the winter, and mixed deciduous-evergreen forests.

The Northwestern Andes constitute a system of ranges that split up into branches in the north and that alternate with deep tectonic depressions. The region is characterized by volcanic activity in the south and glaciers in the highest massifs. The exterior slopes receive abundant precipitation and exhibit a distinct rain ioiest-páramos spectrum of the equatorial-belt altitudinal zone; the interior depressions are covered by savannas, and the extreme north has an arid subequatorial climate and vegetation.

The Equatorial Andes consist primarily of two chains of mountains, which are separated from one another by a basin filled with the products of the activity of numerous volcanoes. The region has a mountain equatorial climate, with a rain forest—páramos spectrum of altitudinal zones. The southwestern foothill plains have a subequatorial climate, with increasing aridity toward the south and a shift in all the natural zones of the belt.

The Peruvian Andes (to 14°30’ S lat.) consist of a series of parallel ranges and high interior plateaus that are deeply dissected by river canyons. The highest ranges have significant glaciation. There are mountain rain forests on the eastern slopes, high mountain jalea steppes on the interior plateaus, and tropical semideserts and. deserts on the western slopes. The Central Andes (to 28° S lat.), which lie entirely in the tropical belt, are the highest and most complex part of the Andes. The principal feature is the Central Highlands with the interior plateau known as the Puna. There is a sharp contrast between the rain forests of the eastern slopes, the arid Puna, which becomes a high mountain desert in the south and has no drainage to the ocean, and the desert landscape of the Pacific west.

The Subtropical Andes (to 41°30’ S lat.) consist of the paired Cordillera Principal and Coastal Cordillera, which are separated from one another by the tectonic Longitudinal Valley. The region is volcanically active, and the amount of precipitation increases rapidly (by latitude) from north to south, which causes a change in all natural processes and landscape types from semi-desert in the north and Mediterranean-type in the center to humid subtropical (rain forests) in the south.

The Patagonian Andes are the southernmost segment of the Andes, where the island archipelagoes replace the Coastal Cordillera and the Longitudinal Valley is supplanted by fjordlike straits. The region has a cool humid climate and abounds in volcanic cones. In the north there are dense mixed forests, primarily evergreen forests; the south has significant glaciation and scrub forests and heaths. Coniferous-deciduous forests grow on the lee slopes, and there are large glacier lakes at the foot of the mountains.

E. N. LUKASHOVA

The first historically substantiated voyage to South America was made in 1498 by C. Columbus, who discovered the island of Trinidad, the section of the South American coast between the delta of the Orinoco River and the Paria Peninsula, and Margarita Island. In 1499–1500 the Spanish expedition of A. de Ojeda, which included A. Vespucci, reached Guiana, at about 5°–6° N lat., and then traveled along the coast of the continent to 72° W long. It rounded the Paraguaná Peninsula and continued southward into the Gulf of Venezuela, reaching Lake Maracaibo. In 1501 the Spaniard R. de Bastidas rounded the Guajira Peninsula,

Figure 1

discovered the mouth of the Magdalena River, and reached the Gulf of Urabá, thus completing the discovery, begun by Columbus, of the entire northern coast of South America.

The northeastern coast of Brazil was first reached in February 1500 at 6° S lat. by the Spaniard V. Pinzón, who then journeyed northwest along the coast to Guiana, discovering en route the southern arm of the Amazon River delta and landing on Marajó Island. In 1500 the Spaniard D. de Lepe followed the Brazilian coast from 6° to 10° S lat. In 1501–02 a Portuguese expedition, probably including Vespucci, explored the Brazilian coast from 5° to 25° S lat., discovering the mouth of the Sāo Francisco River and Guanabara Bay (Rio de Janiero).

In 1507 the Dutch geographer M. Waldseemüller proposed naming the newly discovered southern continent “America,” in honor of Amerigo Vespucci. J. de Solis followed the eastern coast of South America from 25° to 35° S lat. in 1515–16, discovering the La Plata Estuary and the lower reaches of the Uruguay and Paraná rivers. In 1520, F. Magellan journeyed from the La Plata to 52° S lat., discovering the Patagonian coast of South America with all its inlets and the northern coast of Tierra del Fuego. He sailed through the strait later named in his honor to reach the Pacific Ocean. Thus, by 1520, the entire Caribbean coastline and the entire Atlantic coastline of South America and the mouths of all the major rivers had been discovered.

The Pacific coast of South America was explored in the period 1522–58 by seagoing Spanish expeditions. In 1522, P. de Andagoya followed the northwestern coast of South America to 4° N lat. In 1526–27, F. Pizarro explored the coast to 8° S lat., discovering en route the Gulf of Guayaquil, from where in 1532 he embarked on the conquest of Peru. After its conquest and the founding of the city of Lima (1535), Spanish navigators investigated the coast to at least 12° S lat., and later to 40° S lat. after the military expeditions of D. de Almargo (1535–37) and P. de Valdivia (1540–52) into Chile. In 1558, J. Ladrilleros discovered the Chonos Archipelago and the Taitao Peninsula between 44° and 47° S lat. In 1579–80, P. Sarmiento de Gamboa discovered the group of islands between 47° and 52° S lat. In 1616, the Dutchmen J. Le Maire and W. Schouten discovered and rounded Cape Horn (56° S lat.). In 1592 the Englishman J. Davis discovered a body of land in the Atlantic at 52° S lat. In 1594, R. Hawkins, assuming it to be a single body of land, described its northern coast, but J. Strong later proved that it actually consists of two large islands and many small ones and called them the Falkland Islands (1690).

Between 1529 and 1546, while searching for the “golden land of El Dorado,” the Spaniards D. Ordás, P. Hredia, G. Jiménez de Quesada, and S. de Belalcázar and the Germans A. Ehinger, N. Federmann, G. Hohermuth, and P. von Hutten (agents of the German banking houses of the Welsers and Ehingers, who in 1528 had received a patent from Charles V to colonize the southern shore of the Caribbean Sea) discovered the northwestern Andes and Orinoco Llanos and crossed them in all directions and followed the courses of all the large left tributaries of the Orinoco and the Magdalena with the Cauca River. In 1541–42, a group headed by G. Pizarro sailed down the Napo River to the Amazon Lowland, while a detachment led by F. de Orellana separated from the group in 1541 and sailed down the Amazon to the sea, thus completing the first crossing of South America.

In the period 1527–48, while searching for silver in the La Plata Basin, S. Cabot, P. de Mendoza, J. de Ayolas, A. Cabeza de Vaca, and D. de Irala discovered and explored several large rivers of the Paraná-Paraguay system and crossed the Gran Chaco. The lower reaches of the tributaries of the Amazon River were discovered in 1637–39 by the Portuguese expedition of P. Teixeira and B. Acosta, who journeyed up the Para River to the Equatorial Andes and returned back down the river.

In the second half of the 16th century and in the 17th and 18th centuries, the Portuguese mestizos (mamelucos) formed detachments to hunt down Indian slaves and search for gold and precious stones. They crisscrossed the Brazilian Highlands and traced the flow of all the large tributaries of the middle and lower Amazon. In the 17th and the first half of the 18th century, the Upper Amazon system was explored primarily by Jesuit missionaries, including the Czech S. Fritz.

The first scientists to explore South America were French members of the equatorial expedition (1736–43) led by C. de La Condamine and P. Bouguer to measure the meridian arc. Later, during the colonial period, comprehensive scientific studies were made of the La Plata basin by the Spaniard F. de Azara and of the Orinoco River basin by the German A. von Humboldt and the Frenchman A. Bonpland. The exact outlines of South America were largely determined by the British expedition of P. King and R. Fitzroy in the second quarter of the 19th century.

The study of the Brazilian Highlands and Amazon Lowland intensified in the 19th and 20th centuries. Among the scientists who investigated the region were the German W. Eschwege (1811–14), the Frenchman A. de Saint-Hilaire (1816–22), members of the Austro-Bavarian expedition of 1817–20 (K. von Martius, J. Spix, J. Pohl, and J. Natterer), members of G. I. Langsdorfs Russian comprehensive academy expedition of 1822–28, the comprehensive expedition of Comte de Castelnau (F. de la Porte; 1844–45), the Britons A. Wallace (1848–52), H. Bates (1848–58), W. Chandless (1860–69), and J. Wells (1868–84), the German K. von den Steinen (1884 and 1887–88), and the Frenchman H. Coudreau (1895–98).

The Guiana Highlands and the Orinoco River basin were studied by the brothers Robert Schomburgk and Richard Schomburgk, Germans in British service (1835–44), K. Appun, a Pole in British service (1860–72), and the Frenchmen J. Crevaux, H. Coudreau, and J. Chaffanjon (1877–89). In 1887, Chaffanjon discovered the source of the Orinoco River. The American hydrographer T. Page (1853–56) and the Argentine topographer L. Fontana (1875–81) studied the basin of the Rio de La Plata.

Various scientists worked in the Northern and Equatorial Andes, including the Frenchman J. Boussingault (1822–28), the German geologists A. Stübel and W. Reiss (1868–74), the British topographer F. Simons (1878–80 and 1884), the German geographer A. Hettner (1882–84), and the German geographer W. Sievers, who primarily studied the Sierra de Perijá, the Cordillera de Mérida (1884–86), and the Caribbean Andes (1892–93). The German naturalist E. Pöppig (1829–31) and the Frenchman A. d’Orbigny (1830–33) studied the Central Andes. In 1851–69, A. Raimondi, an Italian geographer and topographer in Peruvian service, studied and mapped the Peruvian Andes and the La Montaña region. The Southern Andes, the Chilean-Argentine Cordilleras, and the Patagonian Andes were studied in Chile primarily by Europeans who settled there, including the Pole I. Domeyko (1839–44), the Frenchman A. Pissis (1849–75), and the German botanist R. Philippi (1853–54). In Argentina the English sheep rancher G. Musters crossed Patagonia from south to north and began studying the Chubut River basin (1869–70). Later investigators included the Argentine topographers F. Moreno (1874–97), C. Moyano (1877–81), and L. Fontana (who completed the exploration of the Chubut River basin in 1886–88).

Russian scientists and explorers also conducted extensive studies in South America. Among them were the diplomat and geographer A. S. Ionin (1883–92), the botanist N. M. Al’bov, who studied Tierra del Fuego (1895–96), the ethnographer G. G. Manizer (1914–15), and the botanist and geographer N. I. Vavilov (1930, 1932–33).

I. P. MAGIDOVICH

Anthropological and ethnic composition. Anthropologically, the contemporary population of South America is highly diverse, including representatives of various races, namely, those of the American (indigenous Indian population), Europeoid (descendants of settlers from Europe), and Negroid (descendants of slaves brought from Africa) races, as well as many mixed groups, such as the mestizos, mulattoes, and sambos. Racial intermixing is proceeding rapidly in the South American countries, and new racial types are gradually forming.

Until the appearance of Europeans in the late 15th century, South America was inhabited by various Indian tribes and peoples who spoke Quechua, Arawakan, Chibcha, Tupi-Guaranian, and other languages. The population was unevenly distributed. The high-mountain valleys of the Central Andean Highlands were the most densely populated, while the lowlands of the Amazon Basin were less densely populated. The most highly developed agricultural peoples of the highlands created an early class society (Tawantin-suyu) or were at the point of transition to a class society (Muisca, or Chibcha). The arrival of European conquerors from Spain and Portugal brought about radical changes in the ethnic structure of the continent. Spanish colonists typically penetrated first the most highly developed and densely populated regions, for example, the Central Highlands, where the richest deposits were, and converted them into advance posts for further conquest. The Portuguese conquerors long restricted colonization to the coastal zone of modern Brazil (16th and 17th centuries). The devastating wars of the age of conquest and exploitation during the colonial period sharply reduced the population of many Indian peoples of South America. The intensive mixing between the Spanish and Portuguese colonists and the Indian population began at the very start of the European conquest, with the subsequent dispersal of the racially mixed groups speaking Spanish and Portuguese, respectively. It was these groups that then colonized the La Plata basin, the Pacific coast south of the Central Andes, and other regions of South America and penetrated the interior of modern Brazil.

The arrival of Negroes in South America in the 16th century was linked with the needs of the colonial economy. Thousands of Africans were brought as slaves to work in the mines of the Vice-royalty of Peru and in the sugarcane plantations on the coast of Venezuela and northeastern Brazil. In the Central Highlands the Negroes were assimilated by the local population, while in the two other regions they played a significant part in ethnic processes and cultural development. Large populations of mixed European-Negro and Negro-Indian origin formed there. By the end of the colonial period, in the first third of the 19th century, new racially mixed ethnic groups, speaking Spanish (and Portuguese in Brazil), had formed in most of the regions conquered by the colonists that were separated from one another geographically and were economically self-sufficient. After the countries of South America gained their independence, there were radical changes in the ethnic composition of Argentina, Brazil, and Uruguay as a result of the influx of numerous immigrants from Italy, Germany, and other European countries, enlisted primarily for the development of national territories in the second half of the 19th century and the early 20th century. Immigration from Asia, largely China and India, occurred in Guyana and Surinam.

Most of the present population of South America is of mixed Indian-European background; the population of the northeast is primarily of Negro-European origin. Large Indian groups have survived in several South American countries, for example, the Quechua in Peru, Bolivia, and Ecuador, the Aymara in Bolivia, and the Araucanians in Chile. In addition, small Indian tribes and peoples speaking their own languages have survived in the

Table 2. Political divisions of South America
	Area (sq km)	Population (mid-1977, estimates)	Capital or administrative center
¹ Territory disputed between Great Britain and Argentina ²1976
Source (for population figures): Monthly Bulletin of Statistics, United Nations, July 1978, New York, 1978
Independent states
Argentina ...............	2,766,900	26,060,000	Buenos Aires
Bolivia	1,098,600	5,950,000	La Paz (officially, Sucre)
Brazil ...............	8,512,000	112,240,000	Brazilia
Chile ...............	756,900	10,660,000	Santiago
Colombia ...............	1,138,900	25,050,000	Bogotá
Ecuador ...............	283,600	7,560,000	Quito
Guyana ...............	215,000	830,000	Georgetown
Paraguay ...............	406,800	2,800,000	Asunción
Peru ...............	1,285,200	16,360,000	Lima
Surinam ...............	163,300	450,000	Paramaribo
Uruguay ...............	177,500	2,810,000	Montevideo
Venezuela ...............	912,000	12,740,000	Caracas
Possessions of the capitalist states
Falkland Islands (Islas Malvinas)¹ ...............	12,000	2.000²	Stanley
French possessions French Guiana ...............	91,000	60,000	Cayenne

border regions of almost all the countries, for example, northern Argentina, the Amazon Basin in Brazil, and northwestern Colombia.

The official language in most of the countries of South America is Spanish, except in Brazil, where it is Portuguese. The only Indian languages recognized as official are Quechua in Peru and Aymara in Bolivia. Paraguay has great diversity; most of its people speak the Guarani language and have some mastery of Spanish. The official language of Guyana, Trinidad, and Tobago is English. In the former Dutch colony of Surinam it is Dutch, and in French Guiana it is French.

Most of the believers in South America are Catholic. Vestiges of pre-Christian beliefs play a significant part among the Indians, and vestiges of African cults continue to exist among some Negroes.

I. F. KHOROSHAEVA and A. A. ZUBOV

Spanish and Portuguese navigators arrived in South America in the late 15th and early 16th centuries, thus interrupting the independent development of the indigenous Indian population. Spain and Portugal divided South America according to the Treaty of Tordesillas of 1494, which specified a “line of demarcation” along 46° W long. The conquest of South America, which began in the 16th century, was finished for the most part in the 17th century. By the beginning of the 18th century, most of South America was under Spanish jurisdiction. Portugal controlled almost the entire territory of what is now Brazil, while the northeastern part of South America was divided between Great Britain, France, and Holland.

Colonization was accompanied by the harsh exploitation of the indigenous population, the mass extermination of the population, and the plundering of the mineral resources. The policies of the mother countries, which held back the development of the productive forces, limited the establishment of manufacturing and trade, and prohibited the growing of many agricultural crops, led to frequent uprisings against the colonists. The war of independence of the Spanish-American colonies of 1810–26 put an end to Spain’s colonial domination (seeWAR OF INDEPENDENCE OF THE SPANISH-AMERICAN COLONIES OF 1810–26). All the Spanish colonies gained political independence and formed independent states: Argentina officially declared independence in 1816, Bolivia in 1825, Chile in 1810, Colombia in 1810, Ecuador in 1809, Paraguay in 1811, Peru in 1821, Uruguay in 1825, and Venezuela in 1811. Brazilian independence from Portugal was declared in 1822. However, the countries of South America subsequently became financially and economically dependent on the imperialist countries, especially Great Britain and the United States. After World War I (1914—18), American capital penetrated more intensively and soon occupied a decisive place in the economies of the South American countries. The victory of the Cuban Revolution and the establishment of a socialist system in Cuba fostered a surge in the anti-imperialist revolutionary movement in South America. In the 1960’s and 1970’s, Jamaica, Trinidad and Tobago, Guyana, Barbados, the Bahama Islands, and Grenada freed themselves from colonial dependence. The governments of several countries (Peru since 1968, Chile in 1970–73, and Ecuador since 1972) have begun to carry out anti-imperialist, antioligarchical measures. In 1975, Surinam declared its independence from the Netherlands. (For greater detail on the history of the South American countries, seeLATIN AMERICA.)

REFERENCES

Lukashova, E. N. Iuzhnaia Amerika. Moscow, 1958.
Ocherki po geologii Iuzhnoi Ameriki: Sb. st. Moscow, 1959. (Translated from English.)
Khain, V. E. Regional’naia geotektonika: Severnaia i Iuzhnaia Amerika, Antarktida i Afrika. Moscow, 1971.
Berliand, T. G. Raspredelenie solnechnoi radiatsii na kontinentakh. Leningrad, 1961.
Aeroklimaticheskii spravochnik Iuzhnoi Ameriki. Leningrad, 1968.
Danilina, I. P. “Vliianie obshchei tsirkuliatsii atmosfery i podstilaiushchei poverkhnosti na rezhim atmosfernykh osadkov Iuzhnoi Ameriki.” In Geograficheskiisbornik, fasc. 4. Moscow, 1970.
Vitvitskii, G. N. Tsirkuliatsiia atmosfery v tropikakh. Moscow, 1971.
Klimaty Iuzhnoi Ameriki. Leningrad, 1977.
Karasik, G. Ia. “Vodnyi balans i vodnye resursy Iuzhnoi Ameriki.” In Izv. AN SSSR: Ser. geograficheskaia, 1974, no. 1.
Oroshenie i osushenie v stranakh mira. Moscow, 1974.
Zhukovskii, P. M. Kul’turnye rasteniia i ikh sorodichi, 2nd ed. Leningrad, 1964.
Vtorov, P. P., and N. N. Drozdov. Biogeografiia materikov. Moscow, 1974.
Manizer, G. G. Ekspeditsiia akad. G. I. Langsdorfa v Braziliiu (1821–1828). Moscow, 1948.
Puteshestviia Khristofora Kolumba. Moscow, 1961. (Translated from Spanish.)
Otkrytie velikoi reki Amazonok. Moscow, 1963. (Translated from Spanish.)
Humboldt, A. von. Puteshestvie v ravnodenstvennye oblasti Novogo Sveta v 1799–1804 gg., vols. 1–3. Moscow, 1963–69. (Translated from German.)
Magidovich, I. P. Istoriia otkrytiia i issledovaniia Tsentral’noi i Iuzhnoi Ameriki. Moscow, 1965.
Serra, A. “Clima da América do Sul.” Revista geográfica, 1963, vol. 33, no. 59.
Biogeography and Ecology in South America, vols. 1–2. The Hague, 1968–69.
Geo-Ecology of the Mountainous Regions of the Tropical Americas. Bonn, 1968.
See also references under CENTRAL AMERICA.

South America

[′sau̇th ə′mer·ə·kə] (geography) The southernmost of the Western Hemisphere continents, three-fourths of which lies within the tropics.

South America

the fourth largest of the continents, bordering on the Caribbean in the north, the Pacific in the west, and the Atlantic in the east and joined to Central America by the Isthmus of Panama. It is dominated by the Andes Mountains, which extend over 7250 km (4500 miles) and include many volcanoes; ranges from dense tropical jungle, desert, and temperate plains to the cold wet windswept region of Tierra del Fuego. Pop. (Latin America and the Caribbean): Pop.: 558 281 000 (2005 est.). Area: 17 816 600 sq. km (6 879 000 sq. miles)

South America

South America

South America

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South America

South America

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South America

South America

South America

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noun a continent in the western hemisphere connected to North America by the Isthmus of Panama

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noun the nations of the South American continent collectively

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