Rocky Mountains

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See also: National Parks and Monuments (table)National Parks and Monuments

National Parks
Name Type1 Location Year authorized Size
acres (hectares)
Description
Acadia NP SE Maine 1919 48,419 (19,603) Mountain and coast scenery.
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Rocky Mountains,

major mountain system of W North America and easternmost belt of the North American cordillera, extending more than 3,000 mi (4,800 km) from central N.Mex. to NW Alaska; Mt. Elbert (14,431 ft/4,399 m) in Colorado is the highest peak. The Rockies are located between the Great Plains on the east (from which they rise abruptly for most of their length) and a series of broad basins and plateaus on the west.

The mountains form the Continental Divide, separating rivers draining to the Atlantic and Arctic oceans from those draining to the Pacific. The major Atlantic-bound rivers rising in the Rockies include the Rio Grande, Arkansas, Platte, Yellowstone, Missouri, and Saskatchewan. Those draining to the Arctic include the Peace, Athabasca, and Liard rivers. Flowing to the Pacific Ocean are the Colorado, Columbia, Snake, Fraser, and Yukon rivers.

Formation

The Rockies were formed in the Mesozoic and Early Cenozoic eras during the Cordilleran orogeny. They are geologically complex, with remnants of an ancestral Rocky Mt. system and evidence that uplift, which involved almost all mountain-building processes (see mountainmountain,
high land mass projecting conspicuously above its surroundings and usually of limited width at its summit. Although isolated mountains are not unusual, mountains commonly form ranges, comprising either a single complex ridge or a series of related ridges.
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), occurred as a series of pulses over millions of years. The mountains have since been eroded to expose ancient crystalline cores flanked by thick upturned layers of sedimentary rocks. Glaciers and snowfields, which cover portions of the northern ranges and the high peaks of the south, were at one time more extensive; throughout the system the erosional features of alpine glaciation are apparent.

Topography

Topographically, the Rockies are usually divided into five sections: the Southern Rockies, Middle Rockies, Northern Rockies (all in the United States), the Rocky Mountain system of Canada, and Brooks Range in Alaska. The Wyoming Basin, the system's principal topographic break, is sometimes considered a sixth section.

The Southern Rockies, in New Mexico, Colorado, and S Wyoming, are dominated by two north-south belts of folded mountains that have been eroded to expose cores of Precambrian rocks rimmed by younger sedimentary rocks. The eastern belt comprises the Laramie, Medicine Bow, and Wet Mts. and the Front Range. The principal ranges of the western belt are the Park, Gore, Mosquito, Sawatch, and Sangre de Cristo. Between the two belts are three basins known as the North, South, and Middle "parks." To the southwest are the San Juan Mts., a nonlinear group of uplands composed mainly of volcanic rocks. The Southern Rockies are the system's highest section and include many peaks above 14,000 ft (4,267 m), among them Mt. Elbert and Mt. Massive (14,418 ft/4,395 m), both in the Sawatch Mts.

The Middle Rockies, chiefly in NE Utah and W Wyoming, lie N of the Southern Rockies and are separated from them by the Wyoming Basin. The ranges of this section are generally lower and less continuous than those to the south. The principal parts are the Wasatch and Teton ranges (which are both great tilted fault blocks), the Yellowstone Plateau and Absaroka Range (both developed on volcanic rocks), the Bighorn, Beartooth, Owl Creek, and Uinta Mts., and the Wind River Range (all broad folded mountains). All of these component sections have been eroded down to their Precambrian cores and are rimmed by Paleozoic and Mesozoic sedimentary rocks. The highest peaks of the Middle Rockies are Gannet Peak (13,785 ft/4,202 m) in the Wind River Range and Grand Teton (13,766 ft/4,196 m) in the Teton Range.

The Northern Rockies, in NE Washington, N and central Idaho, NW Wyoming, and W Montana extend N from Yellowstone National ParkYellowstone National Park,
2,219,791 acres (899,015 hectares), the world's first national park (est. 1872), NW Wyo., extending into Montana and Idaho. It lies mainly on a broad plateau in the Rocky Mts., on the Continental Divide, c.
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 to the U.S.-Canadian border. They are composed of the Clearwater and Salmon River Mts., the Sawtooth and Lost River ranges (all of which developed in the batholith of central Idaho), and the Bitterroot Range along the Idaho-Mont. line. In the east are the Front Ranges of Montana. A series of north-south trending ranges separated by narrow trenches and valleys occupies most of N Montana and the Idaho panhandle. Two especially distinctive trenches are the Rocky Mountain Trench, which extends NW from Flathead Lake, and the Purcell Trench, which extends N from Coeur d'Alene Lake. The Okanagan Highlands, in NE Washington, form the western edge of the Northern Rockies. The peaks of the Northern Rockies are generally lower than those to the south; among the highest are Borah Peak (12,655 ft/3,857 m) and Leatherman Peak (12,230 ft/3,728 m) in the Lost River Range.

The Rocky Mt. system of Canada is composed of two major sections: the high rugged peaks of the Canadian Rockies proper, to the east, and the Columbia Mts. group on the west. The Canadian Rockies are located along the British Columbia–Alberta border and include Mt. Robson (12,972 ft/3,954 m; highest peak of the Rocky Mts. in Canada), Mt. Columbia (12,295 ft/3,748 m), and Mt. Forbes (11,902 ft/3,628 m). The prominent, wide-floored Rocky Mountain Trench, west of the crest line, continues c.800 mi (1,290 km) into Canada from Montana and is drained by the headwaters of the Peace River and by sections of the Fraser, Columbia, and Kootenay rivers. The Purcell Trench to the west also crosses into Canada and joins the Rocky Mountain Trench c.200 mi (320 km) north of the border. Farther to the west is the Columbia Mts. group, which includes the Selkirk, Purcell, Monashee, and Cariboo Mts. The Rockies continue into Yukon and the Northwest Territories as the Mackenzie, Richardson, and Franklin Mts. In N Alaska, the Brooks Range, a cold and treeless region rising to Mt. Chamberlin (9,020 ft/2,749 m), forms the northernmost section of the Rocky Mts.

Economy and Natural Resources

Exploitable mineral deposits (lead, zinc, copper, silver, gold) are sparsely dispersed throughout the entire system. The principal mining centers are Leadville and Cripple Creek, Colo.; the Butte-Anaconda district of Montana; Coeur d'Alene, Idaho; and the Kootenay Trail region of British Columbia. In the 1970s oil shale found in the Rocky Mt. area led to an oil industry that spurred city and state growth, especially in Colorado; by the mid-1980s, the industry was already in decline.

Vast forests, largely under government control and supervision, are a major natural resource. Lumbering and other forestry activities are limited mainly to Montana, Idaho, and British Columbia, where commercially valuable stands are most abundant and accessible.

The Rockies are a year-round recreational attraction, and the surrounding states have seen a boom in vacation-housing construction and, thus, population increases since the late 1970s. The U.S. national parks in the system include Rocky Mountain, Yellowstone, Grand TetonGrand Teton National Park
, 309,993 acres (125,503 hectares), NW Wyo.; est. 1929. The park, which includes Jackson Lake and part of Jackson Hole, embraces the most scenic portion of the glaciated, snow-covered Teton Range; Grand Teton (13,766 ft/4,196 m) is the highest peak.
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, and GlacierGlacier National Park,
1,013,572 acres (410,497 hectares), NW Mont.; est. 1910. Straddling the Continental Divide, the park contains some of the most beautiful primitive wilderness in the Rocky Mts.
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. Rocky Mountain National Park (265,723 acres/107,580 hectares) is in central Colorado. Straddling the Continental DivideContinental Divide,
the "backbone" of a continent. In North America, from N Alaska to New Mexico, it moves along the crest of the Rocky Mts., which separates streams with outlets to the west of the divide from those with outlets to the east.
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 in the Front Range of the Southern Rockies, the park features more than 100 peaks towering over 11,000 ft (3,353 m). The highest is Longs Peak (14,255 ft/4,345 m). The park, which was authorized in 1915, also contains many lakes and waterfalls. (See also National Parks and MonumentsNational Parks and Monuments

National Parks
Name Type1 Location Year authorized Size
acres (hectares)
Description
Acadia NP SE Maine 1919 48,419 (19,603) Mountain and coast scenery.
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, table.) In Canada are JasperJasper National Park,
4,200 sq mi (10,878 sq km), W Alta., Canada, in the Canadian Rocky Mts.; est. 1907. It is the second largest of the Canadian scenic national parks and contains many high peaks, glaciers, lakes, hot springs, and streams.
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, BanffBanff National Park,
2,564 sq mi (6,641 sq km), W Alta., Canada, in the Rocky Mts.; est. 1885. Noted for its mountain scenery and mineral springs, Canada's oldest national park is a year-round resort area. Banff and Lake Louise are the chief centers.
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, YohoYoho National Park
, 507 sq mi (1,313 sq km), SE British Columbia, Canada, in the Rocky Mts. at the Alta. border; est. 1886. It lies W of the Continental Divide, adjoining Banff and Kootenay national parks, and contains lakes, glaciers, waterfalls, and high mountains, with a
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, GlacierGlacier National Park,
521 sq mi (1,349 sq km), SE British Columbia, Canada, in the Selkirk Mts.; est. 1886. It contains extensive glaciated areas including Illecilliwaet Glacier. Snowcapped peaks, with densely forested lower slopes include Mt.
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, KootenayKootenay National Park,
543 sq mi (1,406 sq km), SE British Columbia, Canada; est. 1920. In the Rocky Mts. near Kootenay Lake, it contains high peaks, glaciers, deep canyons, and hot springs. The Banff-Windermere Highway crosses the park.
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, Mount RevelstokeMount Revelstoke National Park
, 100 sq mi (259 sq km) SE British Columbia, Canada, in the Selkirk Mts., just E of the Columbia River valley; est. 1914. Situated on a high plateau, rising to c.7,000 ft (2,134 m) at Mt. Revelstoke, the park has several small lakes and glaciers.
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, and Waterton LakesWaterton Lakes National Park,
203 sq mi (525 sq km), SW Alta., Canada, SW of Lethbridge and at the U.S. border, adjoining Glacier National Park, Mont.; est. 1895. It is the Canadian section of Waterton-Glacier International Peace Park, created (1932) by acts of the Canadian
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 national parks.

Passes and Explorers

The Rockies were traversed by westward-bound pioneers; the principal U.S. pass across the mountains is South PassSouth Pass,
broad, level valley (alt. c.7,550 ft/2,301 m), SW Wyo., cutting across the Rocky Mts. It was used by trappers and explorers before Jedediah Smith inaugurated its use as a route for settlers.
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 (alt. c.7,550 ft/2,301 m) at the southern end of the Wind River Range, SW Wyoming, which links the Wyoming Basin and the Great Plains with the basins and plateaus W of the Rockies. This pass was followed by the Oregon and Mormon trails. The Santa Fe Trail skirted the southern end of the Rockies. In Canada the important passes are Kicking Horse (alt. 5,539 ft/1,688 m), which carries the Trans-Canada Highway, Crowsnest Pass, and Yellowhead Pass.

Explorers of the U.S. Rockies have included Vasquez de Coronado (1540), Meriwether LewisLewis, Meriwether,
1774–1809, American explorer, one of the leaders of the Lewis and Clark expedition, b. near Charlottesville, Va. He was a captain in the army and served in a number of campaigns against Native Americans before becoming (1801) secretary to his friend
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 and William ClarkClark, William,
1770–1838, American explorer, one of the leaders of the Lewis and Clark expedition, b. Caroline co., Va.; brother of George Rogers Clark. He was an army officer (1792–96), serving in a number of engagements with Native Americans.
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 (1804–6), Zebulon PikePike, Zebulon Montgomery,
1779–1813, American explorer, an army officer, b. Lamberton (now part of Trenton), N.J. He joined the army (c.1793) and was commissioned second lieutenant in 1799.
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 (1806–7), Stephen LongLong, Stephen Harriman,
1784–1864, American explorer, b. Hopkinton, N.H. As an army engineer, Long was sent on several exploring and surveying expeditions. The first in 1817 was to the region of the upper Mississippi and the Fox-Wisconsin portage; it is recorded in his
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 (1819–20), Benjamin Bonneville (1832–35), John FrémontFrémont, John Charles,
1813–90, American explorer, soldier, and political leader, b. Savannah, Ga. He taught mathematics to U.S. naval cadets, then became an assistant on a surveying expedition (1838–39) between the upper Mississippi River and the Missouri.
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 (1843–44), Isaac Stevens (1853), John W. Powell (1868), and Ferdinand Hayden (1871). Leading Canadian explorers were sieur de la VérendryeVérendrye, Pierre Gaultier de Varennes, sieur de la
, 1685–1749, explorer in W Canada and the United States, b. Trois Rivières (Three Rivers), Que. His father was the sieur de Varennes, for a time governor of Trois Rivières.
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 (1738–39), Sir Alexander MackenzieMackenzie, Alexander,
1822–92, Canadian political leader, b. Scotland. Emigrating (1842) to Canada, he worked first as a stonemason in Kingston, Ont., and then as a builder and contractor in Sarnia. In Lambton he became editor (1852) of a Liberal newspaper.
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 (1792–93), David ThompsonThompson, David,
1770–1857, Canadian geographer, fur trader, and explorer, b. London, England. In 1784 he came to Fort Churchill, Canada, as an apprentice of the Hudson's Bay Company, and until 1797 he was a fur trader of Hudson Bay and in the Athabasca country to the west.
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 (1799–1803), and Simon FraserFraser, Simon,
1776–1862, Canadian explorer and fur trader. Born in Bennington, Vt., he was taken to Canada as a child. He entered the service of the North West Company in 1792, and in 1801 he was made a partner.
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 (1803–7).

Bibliography

See W. W. Atwood, The Rocky Mountains (1945); P. Eberhart and P. Schmuck, The Fourteeners, Colorado's Great Mountains (1970); The Magnificent Rockies, pub. by American West (1973); D. Lavender, The Rockies (1981); H. Chronic, Time, Rocks, and the Rockies (1984); J. McPhee, Rising From the Plains (1986).

Rocky Mountains

 

a mountain system in the western part of North America, in Canada and the United States. The Rocky Mountains extend from 60°N lat. to 32°N lat., a total length of approximately 3,200 km. They are 700 km wide at their widest point. The mountains form the chief part of the eastern belt of the Cordilleras of North America. In a structural and orographic sense the Rocky Mountains comprise two divisions. The Northern Rockies, extending north from 45°N lat., are distinguished by compactness and by the great length of their ranges and valleys, which run from the northwest to the southeast. Many of the peaks rise above 3,500 m (Mount Columbia, 3,747 m; Mount Robson, 3,954 m). The principal orographic element of the Southern Rockies is the Front Range, with a length of approximately 2,000 km. In the west, this range is bounded by a narrow tectonic depression called the Rocky Mountain Trench. The Southern Rockies, extending south from 45°N lat., are more mosaic, and it is here that the system attains its greatest width. Low and high (4,000 m and more) ranges alternate in relief; they run in different directions and are divided by vast plateau-like basins called parks. The highest peak of the Southern Rockies and of the entire system is Mount Elbert (4,399 m).

The Rocky Mountains were formed in the age of Laramide folding (late Cretaceous-Paleogene) and then were subjected to intensive recent uplifting. The northern part of the Rocky Mountains emerged in the area of an ancient foredeep, which separated the Cordilleran geosyncline from the stable part of the North American craton. The Southern Rockies were created on the foundation of ancient cratonic structures that are incorporated into the mobile zone of orogeny. Mountain-forming processes continue today, manifesting themselves in earthquakes and such postvolcanic phenomena as the geysers of Yellowstone National Park. The northern part of the Rocky Mountains is characterized by a complex of landforms from earlier glacial stages. Deposits of gold, silver, copper, and complex ores are confined to the axial parts of the ranges and the massifs composed primarily of Precambrian crystalline rocks. Coal and petroleum deposits are related to sedimentary Paleozoic strata, which form the peripheral parts of the folded ranges.

The Rocky Mountains are located in the temperate and subtropical zones, and the climate is mostly continental. On the peaks and western slopes, precipitation can amount to 1,000 mm a year. The snowline is 4,000 m in the south and 2,500 m in the north. Some of North America’s major rivers, such as the Missouri, Rio Grande, Columbia, and Colorado, originate in the Rockies. The soil and vegetative cover represent several high-altitude zones. In the north there are montane forests (white spruce, alpine fir), elfin forests, alpine tundra, and bald mountains. In the south, the zones include grasslands, parks, primarily pine (western yellow, white, and shore pines), subalpine dark-needled forests (the spruce Picea engelmannii, giant fir), and alpine meadows. The timberline is at an elevation of 3,600 m in the south and 1,200–1,500 m in the north. Mountain fauna includes the grizzly bear, Rocky Mountain goat, argali, and cougar. Among the many parks in the Rocky Mountains are the Jasper, Banff, Yoho, and Glacier national parks (in Canada) and the Rocky Mountain and Yellowstone national parks in the United States.

G. M. IONATEV

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