North America: relief and its features

The relief, minerals of North America - all this is being studied today in school at the lessons of geography. Knowledge of these topics is necessary not only for passing the exam, but for general development. After all, each of us must understand what is the surface of the planet on which we live.

North America, the relief of which we will consider in this article, resembles the type of vertical dismemberment of South America. The powerful belt of the Cordillera mountains stretches along the western coast for 7000 km. The eastern half of this continent is predominantly flat. All this allows us to say that the relief of the North and South America is very similar. However, there are significant differences between these continents. In particular, the Cordillera as a mountain system is much wider and more complex than the Andes (also called the Andean Cordilleras). They consist of a whole system of ridges, differing in tectonic and geological structure, being isolated.

The Eastern Belt

Almost all of the Cordillera's 5 orotectonic longitudinal belts stand out distinctly. The first of them, the eastern one, is the Laramian folding ridges: Mackenzie Mountains, Brooks Ridge, Eastern Sierra Madre Ridge, Rocky Mountains. The latter can be divided into features of orography in two parts: southern and northern. Between them the Yellowstone plateau stands out. Clear straightness of forms is a bright orographic feature.

The foremost mountain range of the Rocky Mountains

The foremost mountain range of the Rocky Mountains (North America) has the following relief: it stretches almost 2000 km along a straight line, striking by the continuity, integrity and uniformity of its geological structure. The mountain range, distinctly expressed, is crowned by steep, high peaks, whose height reaches 4000 m. It gradually descends in the east to the Great Plains. The leading ridge in the west is bounded by a tectonic fault in the northern part. In the middle part of the mountain are lowered. They cross the river Pis, which is one of the sources of the Mackenzie River. The advanced range in the southern part is expanding. It is divided into separate ridges, the height of which is significant: Lewis, Caribou, Selkirk. In this part the largest peaks of the Upper Range are located. It is Mount Robson (height 3954 m) and Mount Columbia (3,747 m). Alpine forms of the relief of North America are typical of the Upper Range. It is also characterized by inaccessibility and significant glaciation.

Rocky Mountains in the South

A single mountain range The Rocky Mountains do not form in the southern part. Here they consist of separate arrays, sometimes isolated and separated by "parks" - wide basins, which are plateau-like plots that connect to the Great Basin Great Plains. Part of the ridges (Sangre de Cristo, Uosatch) stretched almost from north to south. Others (for example, Yuint) - in the west-east direction, perpendicular to them. The considerable height and width of this mountain belt compensates for the lack of continuity. The border between the Great Plains and the Rocky Mountains is very distinct: a steep wall is the slope of the mountains. The southern section is typical epiplatform mountains that were formed after the activation of the edge of one of the ancient platforms.

Belt of inner plateaus and plateaus

The next is the belt of the inner plateaus and plateaus formed in the Nevadian folding on the continent of North America. The relief is characterized by folded Nevadian structures represented by peninsulas. Within this belt, there are plateaus that are confined to the "fragments" of the North American ancient platforms and are clamped by the Cordillera ridges (the Northern Mass, the Colorado plateau). The largest intermountain plains are: Fraser, Yukon, Great Basin, Columbia, Northern and Central Mass, Colorado.

Large Swimming Pool

The Great Basin is a denudation plateau, the largest in area. This territory, the width of which reaches 800 km, as a whole is an alternation of plain and mountain surfaces with a predominance of the first. An average of 1500 m raised the surface of the plateau. However, there are great variations in heights. The highlands are crossed by parallel ridges with altitudes of about 3 km (Wheeler Peak - 3,892 m). Deep hollows, called Bolsons, lie between them. These are semi-enclosed and enclosed basins, which are areas of internal drainage. The Death Valley is one of them (-85 m).

The remains are often found here (including the cones of volcanoes).

The Colorado Plateau and the Grand Canyon

The Colorado Plateau is one of the unique corners of our planet, to which North America is famous. Its relief is very beautiful. According to their geological structure (unbroken horizontal plates of mountain sedimentary rocks of different ages - from Upper Paleozoic to the oldest, lying on a crystalline basement), this plateau is similar to the North American platform. Its surface is a hilly plain whose heights reach 3860 m.

The Plateau is visited by the Grand Canyon (North America). Relief and climate attracts many tourists to this place. The Grand Canyon (pictured below) was formed near the Colorado River, on average. Its depth reaches 1800 m, with a width of 8 to 25 km at the plateau level and up to 1 km at the bottom level. Sheer slopes of an interesting, bizarre shape are characteristic of the Grand Canyon. They arose as a result of processes of erosion destruction and weathering. A meandering narrow bed is embedded in the crystalline basement.

The inner mountain belt

The third belt - the inner mountain range - is the belt of Nevada ridges: the Coast Ridge, the Alaska Range, the Cascade Mountains, the Sierra Nevada, the Transverse Volcanic and the Western Sierra Madre. Straightness is distinguished by these mountain ranges. Magmatic rocks predominate in their structure. Cascade mountains - batholith with volcanic cones, planted on it. The Sierra Nevada range is an asymmetric giant crystal batholith with gentle western and steep eastern slopes.

Belt of synclinoria

The fourth belt is the belt of synclinoria. This is the zone of descent, which took shape in the Neogene. Part of it is currently represented by various sea bays, straits. On land, it is the Death Valley , the Great California Valley, the lower reaches of the Colorado River.

The westernmost belt

The fifth belt is the extreme west. It is a coastal belt of such folded alpine ranges as the Aleutian (there are 25 active volcanoes here), the Kenai Peninsula, the Ostrovnaya Range with the Victoria Peak (2200 m high), the Chugach Range, the Victoria Peninsula, the Coast Ranges, the Southern Sierra Madre Ridge. All of them belong to the medium altitude, only the most outstanding peaks above 2 km.

Depending on the degree of glaciation, the severity of the orographic longitudinal belts, tectonic and erosional dismemberment, the Cordilleras are divided into 4 morphostructural regions: the Cordillera of Mexico, the Cordillera of the USA, the Cordillera of Canada and the Cordillera of Alaska.

Eastern part of the continent

What is the relief in North America in the east? Let's figure it out. As we have already noted, the relief forms of North America are mostly flat in the eastern part of the continent. Basically it is the sublime (Central, Laurentian) and high plains. Low-lying ones are along the coastline: Primixikansky, Priyatlanticheskaya, Priguzonskaya, and Mississippi in the lower reaches of the same river.

Appalachian mountain belt

In North America, unlike the South, another mountain belt stretches along the eastern coast - Appalachian. It is a system of mountain massifs located from the Gulf of St. Lawrence to about 33-32 ⁰ s. , That is, almost 2300 km. The island of Newfoundland is the northernmost link. Appalachians are epiplatform middle mountains. A significant difference between the southern and northern parts of this mountain system determined the features of the tectonic and geological structure. Graben Hudson is the boundary between the Southern and Northern Appalachians. The northern Appalachian Mountains as a whole are a wavy plateau. Above it rise separate mountains, ridges or mountain ranges. The northern Appalachians blocked the Quaternary glaciation. Therefore, the shape of the mountains is now flat, only circuses with steep walls remained on the highest peaks.

Southern Appalachia

The Southern Appalachians are alternating between long parallel valleys and ridges. From the east and west stretches a plateau along the foot of the mountains. This Pidmont in the west is a denudation flat plain, which is formed by Early Cambrian crystalline rocks. From it, in the west, the chain of mountain ranges, almost continuous (Kohuta, Unaka, Black, Smoky, Big, Blue, etc.), steeply rises, the height of which is 1-1.5 km. These are "ancient mountains" - dense nuclei of caledonides, prepared by denudation.

Belt of ridges and valleys

One of the most remarkable areas of the Appalachians is located to the west of them. These are the so-called Young Mountains, or Belt of ridges and valleys. Here are some interesting features of the relief of North America. Sedimentary rocks of the Paleozoic times are the whole territory: ridges - clay shales and sandstones, valleys - dolomites and limestones. Stretched for hundreds of kilometers from the south-west to the northeast along the line of the strike of the mountains, the wide valleys alternate with flat-topped or narrow ridged ridges. At an altitude of 500-600 m lies the bottom of the valleys. The tops of the ridges reach 1-1.2 km. The valleys in the tectonic plan are anticlinoria, and the ridges are synclinoria. That is, in this place there is a clear discrepancy between the type of the tectonic structure of the modern form, which the relief of North America has here. Appalachian photos are presented below.

This is an example of a reversed, or inversion-type relief. It is found in the mountains quite rarely and is represented most clearly in the Appalachians. This type of relief by analogy began to be called "Appalachian relief." The belt of "young mountains" from the west interrupts the Appalachian plateau (Cumberland, Alleghen). It is a ledge whose height is 300-400 m. This plateau is much higher than Pidmont. Its surface at the eastern edge lies at an altitude of about 1.2 km, and at the western side - 500 m. The plateau in places is deeply dissected by valleys of various rivers (gorges with narrow bottoms and steep slopes).

Well, now that the relief of North America has been briefly considered in this article, we hope that it will be easier for you to compose your idea about it.