We explain what the relief of America is like and what it includes, how its formations originated, and what its main characteristics are.
What is the relief of America like?
To understand the relief of America, it is convenient to visualize this vast continent from east to west and briefly describe its orogeny: to the east are the oldest geological formations , today already worn down by erosive factors.
Throughout the entire American West, we find a less ancient orogenic zone, which arose as a result of the collision of the continental plates with the oceanic one, while the central zone has essentially a sedimentary origin .
Next we will analyze the different landforms in America, and their characteristics.
Characteristics of the relief of America :
Almost all of the American territory is above sea level, with a considerable proportion of it even above 1500 meters (with its corresponding cold climates by height). The most marked depression is located in Argentine Patagonia, it is the Laguna del Carbón, which is 105 meters below sea level.
In both North America and South America, the northeast corresponds to shields that originated a long time ago, in the Paleozoic or Primary era. These are the Canadian Shield and the Guyano-Brazilian Shield, respectively.
These systems originated the present formations of the continental east: the Appalachian Mountains (North America), the Brazilian massif; the Guyanas massif and the Patagonian plateau (South America). These are today moderate or low discontinuous elevations, the result of thousands of years of erosion.
Parallel to the extensive coastline of the Pacific Ocean, the western region is dominated by a mountainous relief of large young ridges that corresponds to the Alpine folding produced in the Cenozoic (or Tertiary) era as a result of the collision between the tectonic plates that today form the continent. The western folded massif, which includes the Rocky Mountains of North America, the Sierra Madre (Mexico and Central America) and the great region of the Andes, in South America, correspond to this orogeny.
This forms a large expanse of abrupt shapes with numerous sharp peaks, including the highest peaks on the continent (Aconcagua, 6,960 meters; Tupungato, 6,800 meters; Mc Kinley, 6,200 meters). Only in Central America and for a few hundred kilometers the continuity of the complex is lost, which exhibits great seismic and volcanic activity in some sections and is crossed by narrow valleys.
Within these large groups, others of lesser extension are locally differentiated. For example, the plateaus of Columbia and Colorado, in the United States, or the Altiplano or Puna, in South America.
Between the great mountains of the west and the ancient and eroded reliefs of the east, in the Quaternary period of the Cenozoic era, some rivers were forming large basins and, together with the action of the winds, they were filled in low areas, thus giving rise to the current plains such as the Orinoco river, the Amazon or the Chaco-Pampean plain in South America; or that of the Mississippi River or the great Central Plain in North America.
The action of various agents, such as glaciers or volcanoes, for example, has very slowly modified the relief of the continent.
Between the old eroded mountain ranges of the east, today we find important massifs and mountain groups. It is worth mentioning among them the Laurentian plateau and the Appalachian mountains, the Ozark plateau, the Guyanas massif, the Borborena mountain range, the Brazilian plateau, the Mato Grosso and the Ventania and Tandilia system.
In short, the most representative reliefs of the American continent are three; from highest to lowest seniority:
Plateaus or massifs derived from the old eastern shields (Brazilian plateau, Matto Grosso plateau, Guyanas massif, Laurentine plateau);
Great western cord (Rocky Mountains, Sierra Madre and Cordillera de los Andes);
Great Central Plains (Chaco-Pampean Plain, Amazonian Plain, Great Central Plain of North America).
Valleys, mountains and hills are presented as more local phenomena. Such is the case, for example, of the Sierra Nevada of the United States, in the states of California and Nevada.
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