Terrain Minerals North America - all this is now being studied in the school geography lessons.Knowledge of these issues is necessary not only for the exam, but also for the overall development.After all, each of us must understand that is the surface of the planet on which we live.
North America, a relief which we will cover in this article resembles the type of vertical dismemberment of South America.Powerful belt of mountains of the Cordillera stretches along the western coast to 7000 km.Mostly flat is the eastern half of the continent.All this suggests that the relief of the Americas has a significant similarity.However, between these two continents there are significant differences.In particular, as the Cordillera mountain range is much wider and more difficult to find than the Andes (also called Andean Cordillera).They consist of the whole system ranges differing tectonic and geological structure are distinct.
East Zone
clearly allocated virtually all over the Cordillera 5 orotektonicheskih longitudinal zones.The first of these, the eastern - Laramide orogeny ridges: Mount Mackenzie, Brooks Range, the ridge of the Sierra Madre Oriental, the Rockies.The latter can be divided by orographic characteristics in two parts: north and south.Between them stands abroad Yellowstone Plateau.Accurate straightness forms is bright orographic feature.
Front Range of the Rocky Mountains
Front Range of the Rocky Mountains (North America) has the following relief: it stretches almost 2000 km in a straight line, affecting the continuity, integrity and uniformity of its geological structure.Ridge, clearly expressed, is crowned by steep high peaks, which reach heights of 4,000 meters. He gradually descends to the east of the Great Plains.Front Range on the west by tectonic faults in the northern part.In the middle of the mountain reduced.They crossed the river Peace, one of the sources of the Mackenzie River.Front Range in the southern part of expanding.It is divided into separate ranges, the height of which is considerable: Lewis, Caribou, Selkirk.In this part are the highest peaks of the Front Range.This Mount Robson (height 3954 m) and Mount Columbia (3747 m).Alpine landforms of North America typical Front Range.It is also characterized by rugged and significant glaciation.
Rocky Mountains in the southern part of the One
ridge Rockies do not form in the South.Here they consist of individual arrays, sometimes isolated and separated by "parks" - broad pools, representing plateaus that connect with a large pool Great Plains.Some ridges (Sangre de Cristo, Wasatch) stretched almost from north to south.Others (eg, Uinta Mountains) - in the west-east direction perpendicular to them.A considerable height and width of the mountain belt is offset by the lack of continuity.The boundary between the Great Plains and the Rocky Mountains are very clearly expressed: steep wall - the slope of the mountains.South segment - are typical epi-platformal mountains that were formed after the activation of the edge of one of the ancient platforms.
Belt internal plateaus and plateaus
Next - Belt internal plateaus and plateaus formed in nevadiyskuyu folding on the mainland of North America.The relief is characterized by folded nevadiyskimi structure represented peniplenami.Within this zone, there are plateau, which are confined to "fragments" of ancient North American platform and clamped Cordillera (Northern Mass, the Colorado Plateau).The largest intermountain plain Fraser, the Yukon, the Great Basin, Colombia, North and Central Mass, Colorado.
Great Basin Great Basin - denudation plateau, the largest in area.This area, which reaches a width of 800 km, as a whole is an alternation of plains and rocky surfaces with a predominance of the first.On average, 1,500 m raised surface of the plateau.However, large fluctuations in the heights.The plateau is crossed parallel ridges with heights of about 3 km (Wheeler Peak - 3982 m).Deep depressions, called the Bolson, lie between them.It is semi-enclosed and enclosed basin, which is an area of internal drainage.Death Valley - one of them (-85 m).
remnant peaks are often found (including volcanic cones).
Colorado Plateau and the Grand Canyon
Colorado Plateau - is one of the most unique corners of our planet, which is known for North America.Its relief is very beautiful.In its geological structure (horizontal board undisturbed mountain sedimentary rocks of different ages - from ancient to verhnepaleoziyskih lying on the crystalline basement) is a plateau similar to the North American platform.Its surface - undulating plain, which reaches a height of 3860 m.
Attraction plateau is the Grand Canyon (North America).The terrain and climate in this place attracts many tourists.Grand Canyon (pictured below) was formed from the Colorado River in its middle reaches.It reaches a depth of 1800 m, with a width of 8 to 25 km on a plateau up to 1 km and at the bottom.Steep slopes are interesting, bizarre characteristic of the Grand Canyon.They emerged from the process of weathering and erosion of destruction.The crystalline base of embedded winding narrow channel.
inner mountain belt
third zone - the inner mountain - a belt nevadiyskih ranges: Coast Mountains, the Alaska Range, the Cascade Mountains, the Sierra Nevada, and the Transverse Volcanic Sierra Madre Occidental.Straightness of the difference between these ridges.Igneous rocks are predominant in their structure.Cascade Mountains - batholith with volcanic cones, impaled on it.The ridge of the Sierra Nevada is an asymmetrical giant crystal batholith with steep sloping western and eastern slopes.
Belt synclinoria
fourth belt is a belt synclinoria.This zone is sinking, which took shape during the Neogene.Part of it is currently represented by various marine bays, straits.On land is the Valley of Death, the Great Central Valley, the lower reaches of the Colorado River.
extreme western belt
fifth belt - the extreme west.It is a coastal belt of folded alpine ranges as Aleut (there are 25 active volcanoes), Kenai Peninsula, the Island ridge to the peak of Victoria (altitude - 2200 m), Chugachsky Ridge Peninsula Victoria, Coast Ranges, Range Sierra Madre del Sur.All of them are medium-high, only the most prominent peaks above 2 km.
Depending on the extent of glaciation, the severity of orographic longitudinal zones of tectonic and erosional dissection, the Cordillera is divided into 4 morphostructural region: Cordillera Mexico, Cordillera United States, Canada and the Cordillera Cordillera of Alaska.
eastern part of the continent
What a relief in North America in the east?Let's face it.As we have noted, landforms of North America is mostly flat in the eastern part of the continent.Basically it is exalted (Central, Laurentian) and high plains.Lowland are located along the coastline: Primeksikanskaya, Atlantic region, Prigudzonskaya and Mississippi in the lower reaches of the same river.
Appalachian mountain belt
In North America, in contrast to the South, another mountain belt stretches along the east coast - Appalachian.It is a system of mountain ranges located on the Gulf of St. Lawrence and about 33-320s.m., which is almost 2,300 km.The island of Newfoundland is the northern link.Appalachian Mountains - is epi-platformal high mountains.The essential difference between the southern and northern parts of the mountain range caused particular tectonic and geological structure.Graben Hudson River is the border between the southern and northern Appalachians.Northern Appalachians as a whole - it is undulating plateau.It is dominated by individual mountain ranges, mountain ranges.Northern Appalachian overlap the Quaternary glaciation.Therefore, the forms of the mountains now - gentle, only the highest peaks remained cirques with steep walls.
Southern Appalachian
alternation of long parallel valleys and ridges of different Southern Appalachians.From the east and west of the plateau stretch along the foot of the mountains.This Piedmont in the west - a flat plain of denudation, which is formed by the Early Cambrian crystalline rocks.From it rises steeply to the west a chain of mountain ranges, almost continuous (Kohut, Unakite, black, smoky, big, blue, etc.), Whose height - 1-1.5 km.This is the "old mountain" - dense core Caledonian, the prepared denudation.
Belt ridges and valleys
One of the most remarkable areas of the Appalachian Mountains is located to the west of them.This so-called Young Mountain, or the belt ridges and valleys.Here are some interesting terrain features in North America.Sedimentary rocks of the Paleozoic era is composed of the entire territory: ranges - shales and sandstones of the valley - dolomites and limestones.The stretched for hundreds of kilometers to the south-west to north-east through the stretch of mountains, wide valleys alternate with flat-topped or comb with narrow ridges.At an altitude of 500-600 m is the bottom of valleys.The tops of ridges reach 1-1.2 km.Valley tectonically are anticlinoria and ridges are Synclinorium.That is, at this point is clearly seen mismatch type of tectonic structure of the modern form of which is relief here in North America.Photos of Appalachia is presented below.
This is an example of circulation, or inversion type of relief.It occurs very rarely in the mountains and is represented most vividly in the Appalachians.This type of relief by analogy was called "Appalachian relief."Belt "young mountain" in the west interrupts Appalachian Plateau (Cumberland, Allegheny).It is a projection, the height of which is 300-400 m. This is significantly higher Piedmont plateau.Its surface is at the eastern edge lies at an altitude of 1.2 km, and at the west - 500 m. Dresses are deeply dissected by valleys of different rivers (Gorge with narrow bottoms and steep slopes).
Well, now that the relief of North America was briefly reviewed in this article, we hope it will be easier for him to make his presentation.
