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Elevation layers of North America


summarizing the elevation layers of North America



North America: Elevation layers (4 levels), orographic units, Canadian shield (Velcro)


The North American continent is bounded to the west by the Pacific Ocean, to the north by the Arctic Ocean and to the east by the Atlantic Ocean. In the south there is a connection to the South American continent via a land bridge. The surface formation of the continent is very diverse and is based on geology. Various large natural regions can be differentiated, which will be explained in more detail below. These include:
  • the Cordilleras in the west of the continent,
  • the Great Plains adjoining to the east,
  • the central lowlands with the coastal plains on the Gulf of Mexico and the Atlantic Ocean,
  • the Appalachians,
  • the Canadian Shield, Arctic Lowlands, and the North American Islands



Cordilleras

The Cordilleras stretch from the Arctic Ocean in the northwest along the coast of the Pacific Ocean to Central America and continue into South America. The range of reliefs of the mountain range includes mountain ranges up to well over 4,000 m, deeply cut valleys and high-lying basin landscapes. A subdivision into the eastern Rocky Mountains, the intermontane high basins and the Pacific coastal mountains can be undertaken.

The Rocky Mountains consist of a multitude of individual mountain ranges and mountain ranges, which together form an elongated mountain system. The mountain ranges are mainly oriented northwest-southeast and crossed by valleys of different depths. The great river systems of America, such as the Mississippi system, have their source rivers here and are fed with water from the mountains. The mean heights of the Rocky Mountains are in the northern area between 2,500 and 3,000 m, in the central and southern areas between the 55th and 30th parallel north around 4,000 m.

To the west of the Rocky Mountains are the intermontane high basins. The largest and most important are the Columbia Plateau, the Great Basin and the Colorado Plateau. These are areas that have been raised to an average of 1,500 m through various uplift processes. The basin landscapes are enclosed by the surrounding mountain ranges of the Rocky Mountains and the Pacific mountain ranges.

The Pacific Coast Mountains can be differentiated into two elongated mountain ranges. Between these mountain ranges there are deepened longitudinal valleys that were formed as a result of plate movements of the Pacific and North American plates. The deepest part of the long valleys is the Californian long valley, the height of which fluctuates by 50 m above sea level. The highest point in North America is Mt. McKinley at 6,193 m in the Alaska range in the northwest of the continent.


Great Plains

The Great Plains adjoin the Rocky Mountains to the east and extend to the lake belt that extends from Great Bear Lake in the north over Winniepeg Lake to Lake Michigan and Huron. The area is a layered landscape and is characterized by wide flat plateaus. The plateau landscape is only cut up by deeply cut box valleys, such as the Missouri or Arkansas. Furthermore, the flat, slightly wavy surfaces at the layer edges are limited by steeply sloping layers that mark the transition to the next plateau. The plateaus directly on the Rocky Mountains reach heights of up to 2,000 m, and to the east they gradually drop down to the Mississippi at 300 to 500 m. The northern part of the Great Plains is mainly influenced by the Ice Age. The surface forms here are ground moraines and terminal moraine lines, and the many lakes represent ice age relics.


Central lowlands and southern coastal regions

The central lowlands and the coastal plains join the Great Plains to the southwest. There is a stair-like drop from the plateaus to the lowland areas located approx. 100 m above sea level. In the northeast, the low-lying coastal plains are bounded by the Appalachian Mountains. The lowland areas are predominantly level and flat; towards the interior, the flat areas merge into hilly plains.


Appalachian Mountains

The Appalachians stretch from the southeastern part of the continent to Newfoundland. It is an old fold mountain complex, which is also reflected in the morphological structure. This manifests itself in parallel ridges and valleys in the central part, which, however, are overlaid by fracture formation. In the west, the fold morphology changes into smaller plateaus and in the northeast into hilly lands. The long-acting weathering has leveled the Appalachians, so that a rump mountain has remained. Because of this, the mean heights are only between 1,000 and 2,000 m, the highest point, Mt. Mitchell, measures 2,037 m.


Canadian Shield, Arctic Lowlands and North American Islands

The Canadian Shield stretches across the entire northeast of the continent. It is enclosed by the Great Plains and the Appalachian Mountains. The Canadian shield is one of the oldest units on the continent. Since its formation it has been subjected to intensive removal and leveling. Because of this, a relatively flat relief prevails here, with the mean heights ranging between 200 and 600 m. Only elongated elevations protrude from the uniform surfaces. Furthermore, deep valleys have formed along rivers. As in the northern part of the Great Plains, remnants of glacial formations can be found here in the form of ground and terminal moraines. The plateau landscape merges with Hudson Bay into the Arctic lowlands, which is around 100 m deeper. The mountainous landscape of the North American Islands (Innuitians), on the other hand, extends up to 2,500 m and is strongly structured.


literature

Eisbacher, G. H. (1988): Geology of the Earth. North America. Stuttgart.
Knippert, U. & S. Wagner (eds.) (2003): Alexander-Kombiatlas. Gotha.


Source: Geography Information Center
Author: Wolfgang Koppe
Publisher: Klett
Location: Leipzig
Source date: 2004
Page: www.klett.de
Processing date: 11/24/2011