The relief of North America is closely connected with its tectonic structures. The ancient and young platforms in the modern relief correspond to the plains, the regions of folding in the extreme West and East – the mountains.
Plains occupy 2/3 of the surface. The Canadian shield corresponds to the relief of the Laurentian Upland, whose height is mainly 500-700 m. It was influenced by the ancient glaciation, which reached a maximum stage about 300 thousand years ago and stretched to about 40 ° N. w. Coming from the north, the glacier flattened the protrusions of hard rock, expanded the river valleys, and after melting left glacial deposits – moraine, consisting of a cluster of boulders, pebbles, sand. Slides on the surface, “plowed” by the glacier, were filled
In places of immersion of the crystalline basement of the ancient platform, under the layer of sedimentary rocks, extensive plains appeared in the relief. The central plains affected by the ancient glacier rise to a height of 200-500 m. The great plains formed simultaneously with the mountain rising in the west of the continent, so they rise in giant steps to a height of 1200-1700 m. The young platform on the coast of the Gulf of Mexico corresponds to a number of coastal lowlands, the largest of which is the Primixic lowland.
In the west of the continent, one of the largest mountain systems in the world, the Cordillera, stretches along the middle and young folding belt from north to south. In Alaska, the mountains reach their highest point in McKinley, 6194 m. There are large glaciers here. To the south the mountains are divided into several parallel ridges. The coastline in the west stretches along the Pacific coast, the Rocky Mountains – far to the east. Between them lie such large plateaus as the Great Basin and the Colorado Plateau. As we move south, a large area is occupied by the Mexican Highlands with active volcanoes. The Colorado Plateau is famous for its grandiose canyons. So. The depth of the Grand Canyon of the Colorado River reaches 1800 m.
In the east, within the ancient folding lie the Appalachians – low mountains, up to 2000 m. They consist of a series of longitudinal ridges. Under the influence of the external forces of the Earth, they have collapsed and now have smoothed dome-shaped forms, which resemble our Carpathians. The highest point of the Appalachians is Mitchell.