In my opinion, North America is the most geographically diverse and beautiful region in the world. Traveling around America many times by car, having driven from ocean to ocean, I never ceased to admire its magnificent nature and mesmerizing landscapes. When talking about America in everyday life, we usually talk about its politics or remember famous cities, but we hardly imagine those beautiful creations of nature that the North American continent preserves.
While I support America on many political issues, my main love for her is "geographic." Of course, every country has beautiful places, but the uniqueness of the North American continent lies in the fact that an exceptional variety of scenic natural landscapes accessible thanks to the developed tourism infrastructure. Therefore, I want to talk about the geography of the natural resources of the United States and Canada, about their national parks, landscapes and simply beautiful places where I was lucky enough to visit. It is no coincidence that American National parks Designed to protect the continent's most scenic landscapes and fragile ecosystems, it has been called America's greatest treasure.
The Cordillera of North America - a masterpiece of nature
In the western part of the United States and Canada, the Cordillera mountain system of North America is located, which is a parallel range stretching from north to south and separating them inland plateaus, plateaus and valleys. Along The Pacific the coastal ridges stretch; to the east are located the Cascade Mountains and the Sierra Nevada Mountains related to them; in Canada, the Columbia Mountains are also distinguished; further east are the Rocky Mountains. Between these mountains are the California Valley, the Great Basin, the Columbia Plateau, and the Colorado Plateau. The maximum width of the Cordillera of North America - between San Francisco (California) and Denver (Colorado) - reaches 1,600 km.
This is the most picturesque part of the North American continent with many national parks and other protected areas. Concentrated here a large number of varied landscapes and amazing geological formations - from snow-capped mountain peaks to breathtaking deep canyons, from emerald glacial lakes to colorful geothermal springs, from huge caves to cliffs bizarre shapes... The landscapes of this region make an unforgettable impression.
Many rivers in western North America originate in the Cordilleras. These are rapid mountain streams, the most famous of which are Colorado, Columbia and Fraser. The Cordilleras are home to many beautiful lakes of volcanic or glacial origin, the largest being Lake Tahoe on the California-Nevada border. And on the inner plateaus, there are shallow saline lakes - the remains of reservoirs that existed here in times of a more humid climate, such as the Bolshoye Salt Lake in Utah, called American By the dead sea... The Colorado Plateau is replete with canyons, ledges, outliers and other scenic landforms, the most famous of which is of course the Grand Canyon.
Geologists date the formation of the Cordillera to the second half of the Mesozoic era, about 150 million years ago. This process continued until the beginning of the Cenozoic era, 60 million years ago. Thus, the Cordillera are relatively young mountains, comparable in age to the Alps. For comparison, the history of the Appalachian Mountains located on the east coast of North America began about 480 million years ago.
The westernmost Cordillera mountain range, the Pacific Coast Ranges, stretches 7,250 km across the United States and 1,600 km in Canada. It consists of the Alaska Ridge, the British Columbia Coast Range, the Olympic Mountains in Washington State, the Cascade Mountains and Coast Ranges of the three Pacific states of Washington, Oregon, and California, and the Transverse Ridges in southern california... In addition, the Sierra Nevada Mountains are often included in the Coast Ranges. The first parts will focus on this mountain range system (with the exception of Alaska). And we will start with some distance from the Pacific Ocean inland of the state of California.
Sierra Nevada - snow-capped mountains
Sierra Nevada mountain range, "snow-capped mountains" in Spanish, stretches 750 km along eastern California. The ridge is 110 km wide. High east edge of these mountains, composed mostly of granites, drops abruptly to the Great Basin, and the long western slope slopes relatively gently down to the Central California Valley. Here is the highest point of the continental states (adjacent 48 US states) - Mount Whitney (4421 m); it is only 160 km away from Death Valley, the lowest point in the country.
The Sierra Nevada is one of the oldest mountains in the Cordilleras, almost twice as old as the Rocky Mountains. Their history began about 150 million years ago during the so-called Nevadan orogeny - the first stage of a grandiose geological transformation of the western part of the North American continent. About 2.5 million years ago, during the Ice Age, glaciers began to carve characteristic U-shaped valleys along the entire length of the Sierra Nevada, the most famous of which is Yosemite. The combination of river activity and glacial erosion brought to the surface granite rocks previously located at a depth, leaving only remnants of metamorphic rocks on the tops of the mountains. The ancient granite rocks are known as the "batholiths of the Sierra Nevada". Their age is over 100 million years.
The Sierra Nevada mountains have many alpine lakes, which lead to scenic hiking trails.
Among the attractions of the Sierra Nevada range are the Yosemite and Sequoia National Parks, as well as the alpine Lake Tahoe.
Yosemite - Ice Age Granite Monument
Yosemite national park A UNESCO World Heritage Site, it is one of the largest wildlife conservation areas in the Sierra Nevada region: nearly 95 percent of the park is designated wilderness. The park is renowned for its spectacular granite cliffs, waterfalls and rich biodiversity. The picturesque landscape of the park emerged as a result of the confrontation between the glacier and the granite ridge of the Sierra Nevada: huge masses of ice literally ripped off the top layer of granite, but the walls of the mountains withstood the onslaught. As a result, deep valleys and smooth steep cliffs appear before our eyes, the largest of which rise almost one and a half kilometers above the ground.
The most visited part of the park is the 13 km long glacial U-shaped Yosemite Valley surrounded by granite monoliths, the most famous of which are Half Dome and El Capitan. Half Dome is one of the largest monoliths in North America. Its summit is 2694 m above sea level and 1450 m above the Yosemite Valley.
El Capitan is also one of the largest monoliths in North America. Its summit is at an altitude of 2307 m above sea level and 910 m above the Yosemite Valley.
Yosemite Valley is the centerpiece of the national park. The river Merced flows through it.
From the observation deck Glacier point a panoramic view of the Yosemite Valley opens.
A scenic road runs through the park in the west-east direction Tioga Pass- most high pass in the Sierra Nevada mountains, reaching an altitude of 3031 m. One of the attractions of this road is Lake Tenaya.
Here is located observation deck Olmsted point: a few million years ago, the glacier was polished stone mountains leaving wandering boulders on them.
Beyond the Tioga Pass, at the eastern end of the Sierra Nevada Mountains, is Lake Mono with lime-tuff formations.
The scenic US-395 road runs along the eastern foothills of the Sierra Nevada Mountains.
Sequoia - a giant forest
South of Yosemite is located sequoia national park famous for its giant trees, including a specimen named General Sherman - the largest tree on Earth by volume of wood. The diameter at the base of the tree is 11 m. "General Sherman" has lived on Earth for 2,200 years.
The General Sherman tree grows in the Giant Forest, which contains five of the ten most massive trees in the world, with a volume of up to 1,500 cubic meters of timber.
Another famous giant tree in the park is the second largest tree in the world by General Grant. Since 1926 it has been the National Christmas Tree. "General Grant" is 1700 years old, during which time it has grown by 82 m.
In addition to giant trees, the park has an "attraction" not for the faint of heart: to climb the equipped mountain trail to the dome of a granite monolith Moro Rock, towering 2000 m above sea level. "Stairway to Heaven", built in the 30s of the last century, has a length of 400 m; vertical drop - 90 m.
There are also interesting geological objects in the park, such as Tunnel rock.
Lake Tahoe - an alpine tale
Lake Tahoe in the eastern part of the Sierra Nevada, it was formed several million years ago at the site of a geological fault and reaches a depth of 501 m. It is the largest alpine lake in North America and the second deepest lake in the United States after Crater Lake in Oregon. Tahoe is located at an altitude of 1897 m above sea level; its length is 35 km, width is 19 km; extent coastline 116 km. There are numerous recreation areas and ski resorts around the lake.
Emerald bay- the most beautiful part of the lake.
Northern part of the lake.
Eastern part of the lake.
Bay Zephyr.
The continuation of the Sierra Nevada mountains towards the north is the Cascade Mountains, which will be discussed
Any inhabitant of the North and South America knows where the Cordillera are. The slopes of the ridges in the north. parts of the Cordillera are covered in DOS. coniferous forests. The Cordillera are the source of such large rivers as the Yukon, Mackenzie, Missouri, Columbia, Colorado, Rio Grande and many others.
The Cordillera lie in all geographic zones of America (except for the subantarctic and Antarctic) and are distinguished by a wide variety of landscapes and a pronounced altitudinal zonation. In the northwestern part of the Cordilleras of North America and in the southeast of the Andes, glaciers descend to ocean level; in the hot zone, they cover only the most high peaks.
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The Cordillera are unusual in that they are located on two continents at once. In addition to the Rocky Mountains themselves, it includes the Brooks Ridge in Alaska, the Richardson Ridge and the Mackenzie Mountains in Canada, and the Eastern Sierra Madre mountain range in Mexico. Highest point belt - Mount Elbert, which is located within the state of Colorado.
The Cordillera are some of the highest mountains in the world
It includes the Aleutian, Alaska and Coast Ranges, the Cascade Mountains, the Sierra Nevada mountain range, the Western and Southern Sierra Madre, and the Transverse Volcanic Sierra. It includes the Fraser Plateau, the Columbia Mountains, the Great Basin Highlands, the Colorado Plateau and the Mexican Highlands. In Central America and the islands Caribbean The Cordillera split into three main mountain arcs, which are separated by depressions. The Cordillera of North America are composed of various geological structures of different ages.
Cordillera height - highest point
Due to the very great length in the meridional direction, the climate in the Cordillera varies greatly. In Alaska, Canada and the northwestern United States, on the Pacific slopes, the climate is characterized as rather mild and humid. Mount Rainier National Park is located in the Cascade Mountains, on the territory of which the eponymous volcano is located. These mountains stretch along the western side of the aforementioned continents: from Alaska (northwestern North America) to the island of Tierra del Fuego, which is located near Antarctica.
National parks in the Cordilleras
The Cordillera are one of the highest mountains in the world. Only the Himalayas, as well as several other mountain systems of the central part of Asia, surpass them in height. The influence of these mountains on the formation of culture, traditions, lifestyle of the people of America can hardly be overestimated. In the territory where the Cordillera are located, whole civilizations of the Indians were born, unique in their development and cultural heritage... And on a global scale, the Cordillera mountain range is the watershed between the Pacific basin and the Atlantic Ocean.
Int. some form plateaus, highlands and plateaus - Yukon, Fraser, Columbia, Colorado, Mexican. To the Center. America to the Cordillera are the ridges in the west. coast, incl. xp. Sierra Madre with Tahumulco volcano (4217 m, the highest point of Central America). Glaciers cover approx. 80 thousand km²; most of them are located in the Alaskan mountains. East. the periphery of the Mexican Highlands grow evergreen tropical forests, in the Cordillera Center. America - deciduous rainforests, thorny shrubs, thickets of cacti and secondary savannas.
In the Cordilleras Center. America and the West Indies are distinguished by three mountain arcs: the northern arc follows through the Cayman Islands to Cuba (Sierra Maestra mountains), Haiti (Central southern parts of the interior plateaus are dry steppes and deserts. Cordillera - Cordillera, Colorado River. , the greatest in length (more than 18 thousand km) mountain system of the globe, stretching along the western outskirts of North and South America.
Orography. In KSA, three longitudinal belts are distinctly expressed — eastern, inner, and western. To the west stretch the myo- and eugeosynclinal troughs of the Mesozoids of the Sierra Nevada and the Rocky Mountains (Nevadids). West of the Mesozoic on the Alaska Peninsula and in the California and Oregon Coast Ranges, as well as in the south. Central America the Cenozoic geosynclinal system extends.
Another type is volcanic ridges with a folded base, complicated by a series of volcanoes planted on it, including active ones. On northern slopes the Chugach and St. Elijah mountains, the snow border is at an altitude of 1800-1900 m, on the Alaska ridge - from 1350-1500 m (southern slope) to 2250-2400 m (northern slope).
Rivers and lakes. Within the KSA lie the sources of many river systems of the continent: the Yukon, Peace River - Mackenzie, Saskatchewan - Nelson, Missouri - Mississippi, Colorado, Columbia, Fraser. The largest changes in landscapes are associated with the latitudinal position of the mountain system, with its transition from the subarctic belt to temperate, subtropical and tropical. There are 4 main natural areas: the Northwest, the Canadian Cordillera, the US Cordillera, and the Mexican Cordillera.
To the south, the snow boundary rises to 1500-1800 m in the Coastal Range and up to 2250 m in the Columbian Mountains of Canada. The Cordillera, which occupies the west of North America and extends within the United States proper and Alaska, Canada, and Mexico.
Cordillera Is the largest mountain system in the world. It is located on the west coast of North and South America. That is, it is divided into two approximately equal parts. For this reason, sometimes its southern part, the Andes, is called the longest mountain system (9000 km).
This is partly true, since the Andes, as a separate object, really have a large extent.
The length of the Cordillera is about 18 thousand km. About 9 thousand km for each of its parts - they are almost equal. But if we talk about the size in general, the northern part is larger - it is wider (up to 1600 km). But the southern one is higher - 6962 meters at the highest point (Mount Aconcagua). In the northern part of the Cordillera, the height reaches 6190 meters (Mount Denali), which is also quite a lot. In general, in terms of height, this mountain system is among the leaders, although not in the first place.
Since the Cordillera stretch over great distances, they lie in almost all geographic zones. This means that the conditions here are very diverse. However, something similar is observed along the entire length of the mountains - glaciation. Even in the hottest climatic zones, the mountains have snow caps (due to the relatively great height mountains). The total area of glaciers is 90 thousand km 2.
Cordillera peaks
Although the highest points of the mountain system are located at six thousand meters, the average height of the mountains is 3-4 km. Although, the relief of this geological object is very diverse, so the designation of the height is rather arbitrary.
The highest peaks of the mountain system are:
- - Mount Aconcagua ( dormant volcano) - 6962 meters.
- - Mount Denali (McKinley) - 6190 meters.
- - Ojos del Salado ( largest volcano world) - 6891 meters.
- - Monte Pissis - 6792 meters.
- - Llullaillaco ( active volcano) - 6739 meters
- - Tupungato (active volcano) - 6565 meters.
- - Orizaba Volcano - 5700 meters.
- - The system consists of a large number of mountain arcs, which already gives some uniqueness to the Cordilleras.
You can also note the presence of mountain ranges and depressions that form the rise and fall of the relief - this is very interesting.
- - In the Cordilleras there is a fairly high volcanic activity... True, we are not talking about erupting volcanoes.
- - In the mountains there are large reserves of non-ferrous and ferrous metals, as well as oil and brown coal.
- - Due to the large number of climatic zones, vegetable world The Cordillera is very diverse.
The mountains of America are primarily the Cordillera system - the longest mountain system in the world, which stretches along west coast both Americas (North and South America). Anyone in the Americas knows where the Cordillera are. The slopes of the ridges in the north. parts of the Cordillera are covered in DOS. coniferous forests.
The Cordillera lie in all geographic zones of America (except for the subantarctic and Antarctic) and are distinguished by a wide variety of landscapes and a pronounced altitudinal zonation.
In the northwestern part of the Cordillera of North America and in the southeast of the Andes, glaciers descend to ocean level; in the hot zone, they cover only the highest peaks. The formation of the Cordillera has not yet ended, as evidenced by frequent earthquakes and intense volcanism (more than 80 active volcanoes).
The Cordillera are unusual in that they are located on two continents at once. In addition to the Rocky Mountains themselves, it includes the Brooks Ridge in Alaska, the Richardson Ridge and the Mackenzie Mountains in Canada, and the Eastern Sierra Madre mountain range in Mexico. The highest point of the belt is Mount Elbert, which is located within the state of Colorado.
It includes the Fraser Plateau, the Columbia Mountains, the Great Basin Highlands, the Colorado Plateau and the Mexican Highlands. In Central America and the Caribbean islands, the Cordillera split into three main mountain arcs, which are separated by depressions.
The Cordillera of North America are composed of various geological structures of different ages. Due to the very great length in the meridional direction, the climate in the Cordillera varies greatly. These mountains stretch along the western side of the aforementioned continents: from Alaska (northwestern North America) to the island of Tierra del Fuego, which is located near Antarctica.
The Cordillera are one of the highest mountains in the world.
Only the Himalayas, as well as several other mountain systems of the central part of Asia, surpass them in height. In the territory where the Cordillera are located, whole civilizations of the Indians were born, unique in their development and cultural heritage.
The Cordillera of North America are divided into a number of ridges. Further southeast within Canada and the United States, the Cordillera are called the "Rocky Mountains." Cordillera in the west of the North mainland. America. Int. some form plateaus, highlands and plateaus - Yukon, Fraser, Columbia, Colorado, Mexican. Glaciers cover approx. 80 thousand km²; most of them are located in the Alaskan mountains. East. the periphery of the Mexican Highlands grow evergreen tropical forests, in the Cordillera Center. America - deciduous rainforests, thorny shrubs, thickets of cacti and secondary savannas.
Where are the Cordilleras located?
In the Cordilleras Center. America and the West Indies are distinguished by three mountain arcs: the northern arc follows through the Cayman Islands to Cuba (the Sierra Maestra mountains), Haiti (the central southern part of the inner plateaus is occupied by dry steppes and deserts. meanings, see Cordillera (disambiguation) Part of the western belt is the large mountains - the Cascade, the Sierra Nevada Range and the Transverse Volcanic Sierra.
The relief of North America is varied and contrasting. In the west, the plains adjoin the mountain structures of the Cordilleras. The Cordillera are located within the mountainous West of the mainland. In terms of age, the Cordillera are the youngest part of the mainland, although they began to form in the Mesozoic.
Within this mountain system, three ridge belts are well traced. One of them - the Cordillera proper - is in the west. The second belt, the eastern one, covers the Rocky Mountains. In the extreme north, these ridges converge, in the central part, on the contrary, they diverge.
The Cordillera prevent the penetration of oceanic air masses into the interior of the continent. With the distance from the Pacific Ocean, significant differences between the northern and southern parts of the Cordillera are more and more clearly noticeable. By natural features, this large mountain system can be divided into the following natural countries: the Cordillera of Alaska and Canada, the Cordillera of the United States, the Mexican Highlands, the mountains and islands of Central America.
The mountain ranges of this natural country in the east and west border the Yukon plateau. The development of the mountains has not yet ended, as evidenced by the large number of active volcanoes. Between them and the Sierra Nevada mountains is deep depression California Valley. This is the mountain system of the Appalachian Highlands, stretching along east coast North America. CORDILLIERS OF NORTH AMERICA - a system of mountain ranges and plateaus, part of the Cordillera system and occupying the west. part of the North. America.
Physico-geographical zoning of the Cordilleras
600 - 800 m, and Brooks Mountains, 1200 - 1800 m.
Within Canada, KSA have a southeast. The main uplifts of the Canadian part of KSA are the Rocky Mountains in the E and the Coastal Ridge in the W, have an alpine relief, due to the mean. The coastal range of Canada merges into the Cascade Mountains from the volcanic.
The Cordillera are some of the highest mountains in the world
To the south of the Tehuantepec Isthmus, the mountain belt bifurcates: one branch deviates to E and continues on the Center Islands. America, the other stretches to the Isthmus of Panama. Between Tehuantepec Isthmus and South. In America, the Cordillera are more or less isolated, predominantly. low ridges and massifs.
The snow border in Alaska is at an altitude of 600 meters, on Tierra del Fuego - 500-700 meters, in Bolivia and southern Peru it rises to 6000-6500 meters. The western belt is represented by folded and volcanic ridges that run parallel to the Pacific coast. The inner belt includes a number of plateaus and plateaus located between two other belts. Thus, the arc, which is a structural continuation of the Rocky Mountains and the Eastern Sierra Madre, forms the mountains of the islands of Cuba, northern Haiti and Puerto Rico.
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The mountains began to form in the Jurassic period, a little earlier than the Andes, the formation of which began only at the end of the Cretaceous period. To the north of the 50th latitude, snow supply of watercourses predominates, and to the south - rain supply. Especially many hydropower plants have been built in the Columbia River Basin.
The Cordillera are the source of such large rivers as the Yukon, Mackenzie, Missouri, Columbia, Colorado, Rio Grande and many others. The Cordillera of North America are found primarily in countries such as Canada, the United States and Mexico.
Cordillera(Spanish Cordilleras, literally - mountain ranges), the largest and unparalleled mountain system on the globe. The Cordillera mountain system is also one of the highest mountain systems, second only to the Himalayas and mountain systems. Central Asia.
Geography of the Cordillera mountain system
The Cordillera stretch from the shores of the Arctic in Alaska (66 ° N) in northwestern North America along the western shores of North and South America all the way to southern shores Tierra del Fuego (56 ° S) in the south of South America. The Cordillera on their way pass through many countries of both continents: Canada, USA, Mexico, Central American states, Venezuela, Colombia, Ecuador, Peru, Bolivia, Argentina, Chile. The length of the Cordillera mountain system is more than 18,000 kilometers. The highest elevation is located in South America on the summit of Mount Aconcagua at 6960 meters above sea level, and in North America, the highest peak of the Cordillera corresponds to the peak on Mount McKinley (in Alaska) reaching an altitude of 6193 meters. The Cordillera form a giant barrier between the Pacific Ocean and eastern parts both continents. The Cordillera represent a large divide between two oceans, the Atlantic and the Pacific, and are also the climatic boundary between countries located on both sides of the mountain system. The entire Cordillera mountain system is usually divided into two parts, corresponding to the territories of both continents, these are the Cordillera of North America and the Cordillera of South America, or the Andes. The entire mountain system consists of numerous parallel ridges bordering the discontinuous belt of inner plateaus and plateaus (in North America - the Yukon, Fraser, Columbian, B. Basin, Colorado, Mexican; in the South - Peruvian and Central Indian). North America has three distinct mountain range systems, one of which (the Rocky Mountains) extends east of the plateau zone, the other ridge system extends directly west of this zone (Alaska Ridge, Canada Coast, Cascade Mountains, Sierra Nevada and others) and the third system of mountain ranges runs along the coast of the Pacific Ocean, partly on the coastal islands. Coming to Central America, the Cordillera gradually descend and bifurcate into two branches. One branch runs east along Antilles, the other crosses the Isthmus of Panama and enters the territory of the mainland of South America. The Andes (Cordilleras of South America) in the northern and central parts consist of four, and the rest of the length of two systems of parallel ridges, separated by deep longitudinal depressions or intermountain plateaus.
The highest mountain peaks of the Cordilleras are the ridges of the middle part of the Andes, where the height of individual mountain peaks reaches more than 6700 m (Aconcagua, 6960 m; Ojos del Salado, 6880 m; Sahama, 6780 m; Llullaillaco, 6723 m). The width of the mountain range varies quite a lot, so in North America the width of the Cordillera mountain belt reaches 1600 km, and on the southern continent it reaches only 900 km, which is almost twice less.
The main mountain-building processes, thanks to which the Cordilleras arose, began in North America in the Jurassic period, in South America (where the structures of the Paleozoic Hercynian folding take a large part) - at the end of the Cretaceous period and took place in close connection with the formation of mountain systems on other continents ( cm.
Alpine folding). Mountain-building processes continued actively in the Cenozoic. These processes largely determine the main orographic elements.
The folded structures of the Cordillera are closely associated with the mountain systems of northeast Asia and Antarctica. According to the latest observations, the formation of the Cordillera is far from over, in confirmation of these observations are evidenced by quite frequent and sometimes very destructive earthquakes and intense volcanism, often leading to severe destruction and casualties both among people and among the animal world.
In the active regions of the Cordillera there are more than 80 active volcanoes, of which the most active are Katmai, Lassen Peak, Colima, Antisana, Sangay, San Pedro, Chile volcanoes, etc. Quaternary glaciation also played an important role in the formation of the Cordillera relief, especially to the north of 44 ° N NS. and south of 40 ° S. NS. The Cordillera are rich in minerals. Here I mine significant deposits of copper (especially rich deposits in Chile), zinc, lead, molybdenum, tungsten, gold, silver, platinum, tin, oil, etc.
The climate of the Cordillera mountain system
Due to its great length from north to south, the strong dissection of the relief and the high altitude of the mountains, the result is an exceptional wide variety natural conditions in the Cordillera mountain system. The Cordillera lie in almost all geographic zones of the globe (except for the Antarctic and subantarctic belts).
The climate of the Cordillera is very varied and varies greatly depending on the latitude of the area, the elevation and the exposure of the slopes. The marginal ridges of the Cordilleras are highly moistened in temperate and subarctic belts (western slopes) and in the equatorial and subequatorial belts (mainly eastern slopes). The inner plateaus have a sharply continental climate; in the subtropical and tropical zones they are distinguished by exceptional aridity. Significant parts of plateaus, internal depressions and slopes of ridges, mainly in tropical zones, are occupied by steppes, semi-deserts and deserts. The highly moistened outskirts of the mountains are covered with dense forests. In the temperate zones, coniferous forests (in the north) and mixed forests of evergreen beeches and conifers (in the south) are widely developed, closer to the equator there are mixed (deciduous-evergreen) subtropical and tropical forests. On the humid slopes of the ridges of the equatorial, subequatorial and subtropical belts, there are complex spectra of high belts, from giles to eternal snows. The snow border lies in Alaska at an altitude of 600 m, on Tierra del Fuego 500-700 m, in Bolivia and South Peru it rises to 6000-6500 m.In Alaska and South Chile, glaciers go down to ocean level, in the hot zone they cover only the highest tops.
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| Cordillera | |
|---|---|
Aconcagua |
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| Mountains of north america |
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| Location: | North and South (Andes) America |
| Highest point: | McKinley (6193 m) and Aconcagua (6962 m) |
| Coordinates: | 63 ° 4′10 ″ N 151 ° 0′26 ″ W and 32 ° 39′20 ″ S, 70 ° 00′57 ″ W |
Cordillera, the largest mountain system in the world, stretching along the western outskirts of North and South America, from 66 ° N. (Alaska) to 56 ° S NS. (Tierra del Fuego).
The length is more than 18 thousand km, the width is up to 1600 km in North America and up to 900 km in the South. Located in [Canada, USA, Mexico, Central America, Venezuela, Colombia, Ecuador, Peru, Bolivia, Argentina and Chile.
Almost along the entire length, they are a watershed between the basins of the Atlantic and Pacific oceans, as well as a sharply expressed climatic boundary. In terms of height, they are second only to the Himalayas and the mountain ranges of Central Asia. The highest peaks of the Cordillera: in North America - Mount McKinley (6193 m), in South America - Mount Aconcagua (6960 m).
The whole Cordillera system is divided into 2 parts - Cordillera of North America, and the Cordillera of South America, or the Andes.
The main mountain-building processes that resulted in the emergence of the Cordillera began in North America in the Jurassic period, in South America at the end of the Cretaceous and took place in close connection with the formation of mountain systems on other continents (Alpine folding). The formation of the Cordillera has not yet ended, as evidenced by frequent earthquakes and intense volcanism (more than 80 active volcanoes). Quaternary glaciation also played an important role in the formation of the Cordillera relief, especially north of 44 ° N. and south of 40 ° S latitude.
The Cordillera lie in all geographic zones (except for the sub-Antarctic and Antarctic) and are distinguished by a wide variety of landscapes and a pronounced altitudinal zonation. The snow border in Alaska - at an altitude of 600 m, on Tierra del Fuego - 500-700 m in Bolivia and southern Peru rises to 6000-6500 m.In the northwestern part of the Cordillera of North America and in the southeast of the Andes, glaciers descend to ocean level, in the hot zone, they cover only the highest peaks. The total area of glaciers is about 90 thousand km 2 (in the Cordilleras of North America - 67 thousand km 2, in the Andes - about 20 tons. Km 2).
Literature
- Geographical Encyclopedic Dictionary, M., 1986.
Despite the fact that there are few people living in large areas, the vulnerable nature of the region has been disrupted that are difficult to recover.
Alaska has 13 national parks that protect typical natural complexes as well as local species of animals - mountain sheep, caribou deer, black bear (baribal) and grizzly.
Cordillera of Canada and Northwest United States
This part of the Cordillera system is distinguished by a relatively low mountain height and relative narrowness. It includes the Coast Range of Canada, the Fraser Inner Plateau, the Columbia, and the Rocky Mountains up to about 48 ° N lat. NS. The westernmost orotectonic zone passes here to the islands. Only in the south is the region expanding, as this zone "returns" to the mainland. Its southern border runs along the northern outskirts of the Great Basin and the Sierra Nevada mountains.
Young folded ridges of the coastal zone are fragmented and lowered. The intermontane valleys are flooded with the sea and represent straits and narrow long bays, jutting deep into the land. The coastal ridge continues the Nevada zone, but its height is less than the Alaskan ridge (2000-3000 meters, in the south - up to 4000 meters). It is dissected and processed by glaciers. The coast is fjord-like here.
Some of the general depression of the mountains in the region compared to other parts of the Cordillera is supposedly explained large area glaciation, both ancient and modern. It is possible that the earth's crust here seems to bend under the weight of the ice. The inner plateaus are composed of lava sheets reaching a thickness of up to 1200 meters. They are high (800-1500 meters), but narrow, expanding only to the south (the Columbian Plateau - up to several hundred kilometers). The rivers, cutting through the plateaus, form canyons. The Rocky Mountains consist of a series of longitudinal ridges up to 4000 meters high, separated by valleys and steeply to the east. Along the western slopes stretches a graben filled with glacial deposits - the "Moat of the Rocky Mountains". It is believed to be a continuation of the mid-ocean rift.
The amount of precipitation decreases from west to east (a common pattern for the Cordilleras). The oceanic coast receives 2000-3000 mm per year. The maximum is winter, the snow cover in the mountains reaches an average thickness of 6-9 m. Summers are cool and cloudy. The climate is the same as on the coast of Alaska, only slightly warmer.
Here, as on the coast of Alaska, "rain" coniferous forests grow from Sitka spruce, Douglas, western hemlock, and others with dense undergrowth, epiphytic mosses, and ferns.
On the inner plateaus, features of continentality are manifested: little precipitation (300-400 mm), temperature amplitudes are growing. In the north, there are areas of taiga on podzolic soils, alternating to the south with forest-steppe and steppe. Wormwoods appear in the extreme south. The slopes of the Rocky Mountains are covered with pine forests and shrubs, and the valleys are treeless.
The Cordilleras of Canada have a large number of mountain glaciers of various types.
The region is rich in minerals, both ore (copper, iron, lead, zinc, silver, gold) and non-metallic, such as coal. Forest resources, the hydro potential of rivers are used. Tourism is well developed, especially in the mountains of British Columbia. A number of national parks have been created for nature conservation - Jasper, Banff, Glacier, etc.
Cordillera of the Southwest United States
The physical-geographical country is located approximately between 48 ° and 32 ° N. NS. in the widest and most diverse part of the Cordillera mountain system. The region experienced a general uplift in the Paleogene-Neogene, which was accompanied by faults, denudation, and large erosional dissection.
Here, the manifestations of faults are most clearly visible at the junction of the continental (North American) and oceanic (Pacific) crust. The zones of deep subsidence of the oceanic crust under the mainland in the California region, where there is a huge gap in the coastal areas, are quite clearly visible. The San Andreas Fault stretches northwestward for nearly 900 km. It has existed since the pre-Cretaceous times, and is very active now.
Three structural and morphological zones are clearly traced: axial, the most ancient - Nevada, in the east - Laramian, in the west - young Cenozoic Coastal Ranges, the development of which continues to the present day.
Modern climatic conditions are characterized by high contrast, which is associated with the position in two climatic zones (temperate and subtropical), significant amplitudes of heights, the presence of mountain barriers in the path of sea air masses.
Areas with an annual precipitation of up to 100 mm and maximum temperatures of up to + 57 ° C (Death Valley) are adjacent to the mountains, where annual precipitation is up to 2000 mm, and even in summer freezing temperatures prevail (upper parts of the Sierra Nevada). In the west, it is a Mediterranean-type climate. In the rest of the region in climatic conditions features of continentality appear.
Different parts of the region differ significantly in all components of nature.
The eastern (Laramian) structures of the Rocky Mountains are often referred to as the continental divide with elevations of 1,800 m and above.
The ridges are anticlinal folds that have Precambrian cores. Some of them are elongated in the general direction of the entire mountain system from northwest to southeast (Front Range, Sangre de Cristo, etc.), but there are ridges of a different orientation, sometimes even sublatitudinal. Between them, vast plateau-like areas have formed, connecting the Great Plains with the Great Basin - the so-called "parks". They are composed of sedimentary strata of the Paleozoic-Mesozoic age. The summit areas were covered by the Wisconsin glaciation, and the troughs and kars have been preserved. Spruce-fir and pine forests, the bottoms of "parks" are usually treeless. In the south and along the slopes of the mountains, steppes and semi-deserts rise.
In the northeast is the Yellowstone Plateau ("Yellowstone" in English means "yellow stone") with a Paleogene cover and young lava sheets with a thickness of more than 1000 meters.
It is known as one of the largest regions of the Earth with geysers and thermal springs... Forests of ancient sequoias are buried under thick lava sheets (300-600 meters). Their petrified trunks are often found (there is a section with 12 layers of petrified forest covered with volcanic ash). In 1872, Yellowstone National Park was founded here (an area of about 900 thousand hectares, located at an altitude of 2100 m to 3400 meters). On the territory of the park there are 200 water thermal and mud springs, about 300 geysers. Here the greatest geyser Exilore with a diameter of 8-10 meters griffon "works", which throws water up to 100 meters up. The mineral sediment forms geyserite of various shades - blue, purple, pink, etc. animal world park - bison (their number in comparison with the beginning of the century has increased 20 times and is several hundred heads), a variety of brown bear - grizzly, coyote, fox, skunk, badger, a large predator cougar and 150 species of constantly living birds. The visit to the park is regulated. The park is divided into zones, each of which solves certain tasks: there is a zone of strict protection, where no human influence is allowed, a zone of "controlled" protection (to preserve natural landscapes), a zone of organized tourism and a tourist-administrative zone (campings, parking lots, cafes , administrative buildings).
In the interior of the physico-geographical country to the west of the Rocky Mountains is the largest inland highlands - the Great Basin and the Colorado Plateau.
The Great Basin has undergone a complex history of formation: Paleozoic and Mesozoic folding, Mesozoic sedimentation, intense deformation of structures.
The modern relief was formed in the Cenozoic under the influence of submeridional faults along the rift between the Rocky Mountains and mountain range Sierra Nevada. Clastic material filled the intermontane depressions. Active volcanism manifested itself in the northwest. At present, the rejuvenated relief with numerous internal drainless depressions has a wide range of absolute heights - from 1500-2000 meters to -85 meters (Death Valley). This is the result of powerful vertical movements.
Due to the barrier role of the Cascade Mountains and the Sierra Nevada, which impede the transfer of Pacific air masses, a climate has developed with well-defined features of continentality.
The annual amount of precipitation here does not exceed 90-100 mm. The result of the dry climate is the underdevelopment of the river network, which does not flow into the ocean. There is no removal of degradation products outside the basin; therefore, clastic material buries and levels the mountainous relief.
Within the highlands, there are a hundred relict lakes - Bolshoye Salt (the remnant of Lake Bonneville, most of which the river was lowered. Snake).
Land cover and fauna are typical for deserts and semi-deserts of the temperate and subtropical zones. America has a different look than the deserts of Eurasia.
Along with saline and rocky deserts, there are areas with a pronounced seasonality, when ephemera bloom brightly in spring. In the southern part of the basin, a “sparse forest” of cacti (up to 10 meters high) and yucca has formed. Pines and junipers with steppe grasses grow on the slopes of the ridges. The Sonoran Desert in Arizona is picturesque. The hilly plain is composed of sedimentary rocks and has insular volcanic mountains. The desert is inhabited by many species of cactus, including the giant tree-like squorow. The volcanic mountains overgrown with this plant seem to be covered from afar rare forest devoid of small branches and leaves. The age of cacti is tens and hundreds of years, the height is 10-12 meters, the trunk thickness is up to 70 cm, coyotes and many poisonous snakes live under them. In addition to cacti, other xerophytic plants also grow in Sonora, which can tolerate not only drought, but also extremely high air and soil temperatures. The fauna of the desert is diverse and interesting.
The Colorado Plateau is an area of horizontal bedding of Phanerozoic rocks of different lithological composition. Highly elevated structural plain (in some places more than 3500 meters) is framed by cuestas.
The deeply incised river network has created canyons with steep slopes, on which all the rocks of different colors that make up the plateau are exposed. On the outskirts of the plateau, volcanic rocks are widely represented in the form of intrusions and laccoliths. The main watercourse is r. Colorado, which carved the plateau to create the Grand Canyon. The main canyon has a winding shape, its depth is 1800 m, its maximum width is up to 25 km, and its length is more than 300 km.
To the west of the inner plateaus are Nevada structures - the Sierra Nevada mountains. This is a large block structure (a horst block with ridge-like tops), the blocks are inclined to the west, and there are batholiths at the base. The Cascade Mountains are a prime example of a volcanic ridge with a number of active volcanoes. Folded structures within them are overlain by Cenozoic lavas, and high (some over 4000 m) volcanic cones are planted on them. Among them there are very active ones: in the 80s. XX century Volcano St. Helens erupted for two years in a row, there were many casualties. There are also extinct, but showing post-volcanic activity.
The vegetation of the mountains is typically American.
Here in the valley of the river. Merset (Yosemite Valley) preserved forest (park) of the giant sequoiadendron. For their large size (the height of many trees reaches 80-100 meters) and for bending like the tusks of a mammoth, their branches were called mammoth trees. In the lower tier of the mountains - chaparral (American variety of maquis).
Coastal ridges - low (up to 2400 meters) Pacific structures are separated from the Nevada structures by the Willamette and California valleys. It is the result of subduction with the latest strike-slip faults such as San Andreas.
This rift is especially active. Blocks of the earth's crust are shifting horizontally relative to each other at high speed. The process is accompanied by strong earthquakes. For example, in 1992, 150 km from Los Angeles, an earthquake occurred in the Mojave Desert, during which more than 5000 tremors of various strengths were recorded in 10 days. Are affected by tremors big cities- San Francisco was badly destroyed in 1906, in Los Angeles there were shocks of 7-8 points in 1971.
The climate here is subtropical with a humid warm winter(up to 10 ° C) and dry summer. On the coast, the summer is cool (average July temperatures are about 15 ° C): the influence of air masses with the northern component and the cold current affects. When moving inland, summer becomes much warmer (20-22 ° C). The annual precipitation is 500-600 mm with a winter maximum. The lower tier of the mountains is occupied by an analogue of the Mediterranean maquis - chaparral (thickets of bush oak, deciduous and evergreen, 1.5-2 meters high, less often - 3 meters, on brown, above 600 meters - stony soils). In the south - thickets of acacia, cactus, yucca. The upper tiers are dominated by coniferous forests of Sitka spruce, Douglass, pines, and sequoias.
On the northern parts of the western slopes, there are national parks, where forests of evergreen sequoia (mahogany) are taken under protection. National park Redwood is located north of San Francisco, in the valley of the river. Redwood Creek. Sequoias are the tallest and oldest trees, along with mammoth trees from the same family. Sequoia grows up to 2000 years. The phytomass of a thousand-year-old sequoia is more than 4000 thousand c / ha (1% is needles, the rest is trunk and branches), the output of commercial wood is 10 thousand m 3 / ha. Trees are not afraid of fires.
Of all regions of North America, the Cordillera of the Southwest of the United States stands out for a variety of natural attractions that attract tourists from all over the world.
In addition to recreational, this region has good agro-climatic and land resources. In the Great California Valley, the natural vegetation of dry wormwood steppes and semi-deserts has been completely replaced by cultural ones. A variety of subtropical crops are grown on the lands irrigated by the waters of rivers flowing from the mountains. On the coast of the Pacific Ocean, giant urban agglomerations have formed, connected by highways. From Richmond, Oakland, San Francisco to Los Angeles, including the famous Hollywood, there is a continuous urban development.
The most acute problem is pollution: all harmful emissions remain at the surface of the earth, since the anticyclonic regime and descending air currents prevail for a significant part of the year. Fogs are frequent.
