Physical geography of the Americas

We explore the physical geography of the Americas, and explain how the major landforms were shaped. In addition, we describe their geologic features.

What is the physical geography of the Americas like?

The physical geography of the Americas is remarkably diverse. Among its main land features are the Andes, which run north-south along the western portion of South America, and the great plains in the east. The average elevation is 2,460 feet (750 m) above sea level.

The Americas present very old landforms, such as the Canadian Shield in North America and the Guiana Shield in South America, which date back to Precambrian times and are composed of rocks over 600 million years old. These landscapes are characterized by low elevation and gentle slopes.

Conversely, the higher and steeper landforms of the continent are younger in geologic time, and are marked by important seismic and volcanic activity.

• See also: Physical geography of Europe

Characteristics of the land relief of the Americas

The land relief of the Americas is made up of three major types of landforms: plains, plateaus, and mountain and volcanic chains.

• Plains. They spread over much of the central and eastern portion of the Americas. They cover a total area of about 6.6 million sq mi (17 million km²), which accounts for 40% of the continent’s total. These plains are young in geologic time, as they were formed during the Cenozoic Era. They are traversed by major rivers including the Mississippi, Amazon, and Paraná.
• Plateaus. They are composed of very old massifs formed during the Precambrian and Paleozoic eras. These landforms are highly eroded and are relatively flat, without the presence of high elevations. The Canadian Shield, the Altiplano, and the Patagonian Massif are some of the most important plateaus on the continent.
• Mountain and volcanic ranges. Parallel to the Pacific Coast run the Andes. This mountain range is young in the geologic time scale, forming in the Cenozoic Era as a result of the collision between tectonic plates. It consists of high-altitude mountains and volcanoes.

Mountains, plateaus, and plains of the Americas

The major landforms of the Americas are:

Plains	Chaco-Pampean Plain. It covers a total area of about 502,000 sq mi (1.3 million km2), spanning parts of Argentina, Paraguay, Uruguay, Brazil, and Bolivia. Amazon Plain. With an area of about 2.32 million sq mi (6 million km2), it covers parts of Brazil, Peru, Ecuador, Colombia, and Venezuela. Great Plains. Covering a total area of about 1.12 million sq mi (2.9 million km2), they spread over parts of the United States and southern Canada.
Plateaus	Brazilian Highlands. Situated in Brazil, it spans an area of about 1.54 sq mi (4 million km2). Mato Grosso Plateau. Located in Brazil, it has an average elevation of 1,640 feet (500 m) above sea level. Guiana Shield. It stretches across parts of Venezuela, Guyana, French Guiana, Suriname, and Brazil. Laurentian Plateau. It covers much of northern Canada and a small portion of Greenland. Altiplano. It lies over the north of Chile and Argentina, and the south of Bolivia and Peru. It is an elevated plateau, which stands at over 12,470 feet (3,800 m) above sea level.
Mountains	Rocky Mountains. They lie in the western edge of North America. At 14,439 feet (4,401 m), Mount Elbert is the highest peak, located in the United States. Sierra Madre. Mexico is home to the mountain ranges of the Sierra Madre Oriental, Occidental, and del Sur. The highest peak is the Citlaltépetl volcano in the Sierra Madre Oriental, at 18,491 feet (5,636 m). The Andes and the Cordillera. Stretching from Patagonia in Argentina to Alaska in the United States, its highest elevation point, Mount Aconcagua, is the highest peak on the continent, at 22,831 feet (6,959 m).

How was the land relief of the Americas shaped?

The Americas lie on the North American, South American, Caribbean, and Pacific plates. The movement and convergence between these plates and those of the Atlantic and Pacific Oceans (the Nazca, Cocos, Scotia, and Juan de Fuca plates) shaped much of the continent's highest elevations.

The Andes and the Cordillera formed as a result of the collision between the South American plate and the Nazca plate, and, in turn, the North American plate with the Pacific plate. This geologic process is relatively recent, having occurred during the Cenozoic Era in the Tertiary Period, about 65 million years ago.

The formation of the mountains and volcanoes that make up the Andes and the Cordillera was followed by the emergence of the extensive plains in the central and eastern portion of the continent. Most of these lowlands were shaped during the Cenozoic Era in the Quaternary Period, about 2.5 million years ago.

Explore next:

• Asia
• Africa
• Continents
• Central America

References

• Cátedra Uno (s.f). Relieve de Europa CatedraUno
• Valverde, S. y otros (2010). Una geografía del mundo para pensar. Editorial Kapelusz. 
• Tarbuck, E. y Lutgens, F (1999). Ciencias de la Tierra. Una introducción a la geología física. Prentice Hall.