South America

Article Outline

Introduction; The Natural Environment; The People; Patterns of Economic Development; History

Introduction

South America, fourth largest of the Earth's seven continents (after Asia, Africa, and North America), occupying 17,820,900 sq km (6,880,700 sq mi), or 12 percent of the Earth's land surface. It lies astride the equator and tropic of Capricorn and is joined by the Isthmus of Panama, on the north, to Central and North America. The continent extends 7,400 km (4,600 mi) from the Caribbean Sea on the north to Cape Horn on the south, and its maximum width, between Ponta do Seixas, on Brazil's Atlantic coast, and Punta Pariñas, on Peru's Pacific coast, is 5,160 km (3,210 mi).

South America has a 2007 estimated population of 380 million, or 6 percent of the world's people. The continent comprises 12 nations. Ten of the countries are Latin: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, and Venezuela. Two of the nations are former dependencies: Guyana, of the United Kingdom, and Suriname, of The Netherlands. South America also includes French Guiana, an overseas department of France. Located at great distances from the continent in the Pacific Ocean are several territories of South American republics: the Juan Fernández Islands and Easter Island (Chile) and the Galápagos Islands (Ecuador). Nearer the coast, in the Atlantic Ocean, is the Fernando de Noronha Archipelago, which is a Brazilian territory, and, farther south, the British dependency of the Falkland Islands, which is claimed by Argentina as the Islas Malvinas. The coastline of South America is relatively regular except in the extreme south and southwest, where it is indented by numerous fjords.

The Natural Environment

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South America consists of four upland provinces, extending inland from the coasts, and, between them, three lowland provinces. The northern and western fringes are dominated by the Andes Mountains, the second highest mountain range in the world. Most of the eastern coast is fringed by the broader—and generally less elevated—highland areas of the Guiana and Brazilian massifs and the Patagonian Plateau. The main lowland is the vast Amazon Basin in the equatorial part of the continent; it is drained by the Amazon River, the world's second longest river. The Orinoco River drains a lowland in the north; to the south lies the Paraguay-Paraná basin. The lowest point in South America (40 m/ 131 ft below sea level) is on Península Valdés in eastern Argentina, and the greatest elevation (6,960 m/22,834 ft) is atop Aconcagua in western Argentina, the highest peak in the Western Hemisphere.

Geological History

The oldest and most stable structural element of the continent is the shield area of the Brazilian and Guiana highlands of the east and northeast. It comprises a Precambrian (before 570 million years ago) complex of igneous and metamorphic rocks. In most places the shield is overlaid by sedimentary rocks, mostly of Paleozoic age (570 million to 225 million years ago), although some areas of younger basalts occur, notably in southern Brazil. Fossils found in the Brazilian Highlands offer evidence of continental drift, indicating that in the Permian period the continent was linked to Gondwanaland, a great landmass incorporating Africa and Asia.

Natural Regions

Rising abruptly from the northwestern and western coasts of the continent are the Andes. They consist of a single chain in Venezuela, in the north, and through much of Chile and Argentina, in the south, but the central part of the mountain system consists of two or three parallel axes of mountains, known as cordilleras, or ranges. In southwestern Bolivia and southern Peru, a region of large intermontane plateaus called the Altiplano separates the ranges. In Peru and Argentina the ranges are separated by relatively narrow but deep valleys. Among the two dozen peaks that exceed an elevation of 17,000 ft (equivalent to 5,182 m) are a number of active volcanoes located in south central Chile, southern Peru and Bolivia, and Ecuador.

The vast uplands of Guiana, in the northeast, and of Brazil, in the east, have rolling to hilly surfaces, with broad plateaus and high mesas. The plateaus are higher and less broad in the highlands of Guiana. In the Brazilian Highlands, the greatest relief occurs in mountains that lie along the eastern coast, in many places rising abruptly from the sea. In general, the rocks of these uplands have weathered into infertile, reddish soils. Fertile soils derived from basaltic rocks are found in many valleys, however. To the south is the less elevated and relatively flat Patagonian Plateau (see Patagonia). Although soils here are generally fertile, climatic constraints limit their agricultural usefulness.

The northernmost of the continent's principal lowland areas is the Orinoco Basin, which includes the Llanos—a region of alluvial plains and low mesas—and a vast system of valleys that converge toward the Amazon between the Caquetá and Madeira rivers. The Amazon Basin itself is a region of slightly rolling terrain. Farther south are the shallow valleys and flat plains of the Gran Chaco and the Pampas, both of which merge with the swampy floodplains of the Paraguay and Paraná rivers.

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Introduction

The Natural Environment

Geological History

Natural Regions