Mountain A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them. The study of mountains is Orology. There is no universally-accepted definition of mountain. In the United States, the following points of measurement have been used and taught in geography classes: • Flat to 500 feet, base to highest point - Rolling Plain • Highest point 501 to 999 feet above base - Hill • Highest point 1000 feet or more above base - Mountain Whether the landform is called a mountain may depend on usage among the local people. The highest point in San Francisco, California, is called Mount Davidson, notwithstanding its height of 990 feet, which makes it ten feet short of the minimum for a mountain in American appellation. Other definitions of "mountain" include: [1] • Height over base of at least 2,500m • Height over base of 1500-2500m with a slope greater than 2 degrees • Height over base of 1000-1500m with a slope greater than 5 degrees • Local (radius 7km) elevation greater than 300m, or 300-1000m if local (radius 7km) elevation is greater than 300m By this definition, mountains cover 64% of Asia, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous and 10% of people live in mountainous regions.[2] Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.[3][4] The 50 tallest mountains in the world are in Asia. Exogeology deals with planetary mountains, which in that branch of science are usually called montes (singular - mons). The highest known mountain in the Solar System is Olympus Mons on the planet Mars (elevation 21,171 m). Characteristics High mountains, and mountains located close to the Earth's poles, reach into the colder layers of the atmosphere. They are consequently subject to glaciation, and erosion through frost action. Such processes produce the peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan. Mountains can be eroded and weathered, altering their characteristics over time. Tall mountains have different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes. The flora and fauna found in these zones tend to become isolated since the conditions above and below a particular zone will be inhospitable to those organisms. These isolated ecological systems are known as sky islands and/or microclimates. Alpine forests are forests on mountain sides. Mountains are colder than lower ground, because the Sun heats Earth from the ground up. The Sun's radiation travels through the atmosphere to the ground, where Earth absorbs the heat. Air closest to the Earth's surface is, in general, warmest (see lapse rate for details). Air temperature normally drops 1 to 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) for each 300 meters (1000 ft) of altitude. Mountains are generally less preferable for human habitation than lowlands; the weather is often harsher, and there is little level ground suitable for agriculture. At very high altitudes, there is less oxygen in the air and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3,500 meters (11,483 ft). Mountains and mountain ranges throughout the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility is affected by height, steepness, latitude, terrain, weather. Roads, lifts, or tramways affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts. Types of mountains Mountains can be characterized in several ways. Some mountains are volcanoes and can be characterized by the type of lava. Other mountains are shaped by glacial processes and can be characterized by their glaciated features. Still others are typified by the faulting and folding of the Earth's crust, or by the collision of continental plates via plate tectonics (the Himalayas, for instance). Shape and placement within the overall landscape also define mountains and mountainous structures (such as butte and monadnock). Finally, mountains can be characterized by the type of rock that make up their composition. Geology A mountain is usually produced by the movement of lithospheric plates, either orogenic movement or epeirogenic movement. The compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, a mountain. The absolute heights of features termed mountains and hills vary greatly according to an area's terrain. The major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Two types of mountain are formed depending on how the rock reacts to the tectonic forces – block mountains or fold mountains. Compressional forces in continental collisions may cause the compressed region to thicken, so the upper surface is forced upward. In order to balance the weight of the earth surface, much of the compressed rock is forced downward, producing deep "mountain roots" [see the Book of "Earth", Press and Siever page.413]. Mountains therefore form downward as well as upward (see isostasy). However, in some continental collisions part of one continent may simply override part of the others, crumpling in the process. Some isolated mountains were produced by volcanoes, including many apparently small islands that reach a great height above the ocean floor. Block mountains are created when large areas are widely broken up by faults creating large vertical displacements. This occurrence is fairly common. The uplifted blocks are block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley. These areas often occur when the regional stress is extensional and the crust is thinned. The mid-ocean ridges are often referred to as undersea mountain ranges due to their bathymetric prominence. Rock that does not fault may fold, either symmetrically or asymmetrically. The upfolds are anticlines and the downfolds are synclines; in asymmetric folding there may also be recumbent and overturned folds. The Jura mountains are an example of folding. Over time, erosion can bring about an inversion of relief: the soft upthrust rock is worn away so the anticlines are actually lower than the tougher, more compressed rock of the synclines. Rocky Mountains From Wikipedia, the free encyclopedia Jump to: navigation, search Rocky Mountains Rockies Mountain range
Moraine Lake, and the Valley of the Ten Peaks, Banff National Park, Alberta, Canada Countries Canada, United States British Columbia, Alberta, Idaho, Montana, Wyoming, Regions Utah, Colorado, New Mexico Part of
Pacific Cordillera
Highest pointMount Elbert
- elevation - coordinates
Geology Period
14,440 ft (4,401 m)
39°07′03.90″N 106°26′43.29″W / 39.11775°N 106.4453583°W Igneous, Sedimentary, Metamorphic Precambrian, Cretaceous
The Rocky Mountains, often called the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 4,800 kilometres (2,980 mi) from the northernmost part of British Columbia, in Canada, to New Mexico, in the United States. The range's highest peak is Mount Elbert in Colorado at 14,440 feet (4,401 m) above sea level. Though part of North America's Pacific Cordillera, the Rockies are distinct from the Pacific Coast Ranges (as named in Canada) or Pacific Mountain System (as known in the United States), which are located immediately adjacent to the Pacific coast. The eastern edge of the Rockies rises impressively above the Interior Plains of central North America, including the Front Range of Colorado, the Wind River Range and Big Horn Mountains of Wyoming, the Bridger Mountains and the Rocky Mountain Front of Montana, and the Clark Range of Alberta. In Canada geographers define three main groups of ranges: the Continental Ranges, Hart Ranges and Muskwa Ranges (the latter two flank the Peace River, the only river to pierce the Rockies, and are collectively referred to as the Northern Rockies). Mount Robson in British Columbia, at 3,954 metres (12,972 ft), is the highest peak in the Canadian Rockies. The Muskwa and Hart Ranges together comprise what is known as the Northern Rockies (the Mackenzie Mountains north of the Liard River are sometimes referred to as being part of the Rockies but this is an unofficial designation). The western edge of the Rockies includes subranges such as the Wasatch near Salt Lake City and the Bitterroots along the Idaho-Montana border. The Great Basin and Columbia River Plateau separate these subranges from distinct ranges further to the west, most prominent among which are the Sierra Nevada, Cascade Range and Coast Mountains. The Rockies do not extend into the Yukon or Alaska, or into central British Columbia, where the Rocky Mountain System (but not the Rocky Mountains) includes the Columbia Mountains, the southward extension of which is considered part of the Rockies in the United States. The Rocky Mountain System within the United States is a United States physiographic region; the Rocky Mountain System is known in Canada as the Eastern System. Geography and geology The Rocky Mountains are commonly defined as stretching from the Liard River in British Columbia south to the Rio Grande in New Mexico. Other mountain ranges continue beyond those two rivers, including the Selwyn Range in Yukon, the Brooks Range in Alaska, and the Sierra Madre in Mexico, but those are not part of the Rockies, though they are part of the American cordillera. The United States definition of the Rockies, however, includes the Cabinet and Salish Mountains of Idaho and Montana, whereas their counterparts north of the Kootenai River, the Columbia Mountains, are considered a separate system in Canada, lying to the west of the huge Rocky Mountain Trench, which runs the length of British Columbia from its beginnings in the middle Flathead River valley in western Montana to the south bank of the Liard River. The Rockies vary in width from 70 to 300 miles (110 to 480 kilometers). Also west of the Rocky Mountain Trench, farther north and facing the Muskwa Ranges across the trench, are the Stikine Ranges and Omineca Mountains of the Interior Mountains system of British Columbia. A small area east of Prince George, British Columbia on the eastern side of the Trench, the McGregor Plateau, resembles the Rockies but is considered part of the Interior Plateau. The younger ranges of the Rocky Mountains uplifted during the late Cretaceous period (100 million – 65 million years ago), although some portions of the southern mountains date from uplifts during the Precambrian (3,980 million – 600 million years ago). The mountains' geology is a complex of igneous and metamorphic rock; younger sedimentary rock occurs along the margins of the southern Rocky Mountains, and volcanic rock from the Tertiary (65 million – 1.8 million years ago) occurs in the San Juan Mountains and in other areas. Millennia of severe erosion in the Wyoming Basin transformed intermountain basins into a relatively flat terrain. The Tetons and other north-central ranges contain folded and faulted rocks of Paleozoic and Mesozoic age draped above cores of Proterozoic and Archean igneous and metamorphic rocks ranging in age from 1.2 billion (e.g., Tetons) to more than 3.3 billion years (Beartooth Mountains).[1] Periods of glaciation occurred from the Pleistocene Epoch (1.8 million – 70,000 years ago) to the Holocene Epoch (fewer than 11,000 years ago). Recent episodes included the Bull Lake Glaciation that began about 150,000 years ago and the Pinedale Glaciation that probably remained at full glaciation until 15,000–20,000 years ago.[1][2] Ninety percent of Yellowstone National Park was covered by ice during the Pinedale Glaciation.[1]The little ice age was a period of glacial advance that lasted a few centuries from about 1550 to 1860. For example, the Agassiz and Jackson glaciers in Glacier National Park reached their most forward positions about 1860 during the Little Ice Age.[1] Water in its many forms sculpted the present Rocky Mountain landscape.[1] Runoff and snowmelt from the peaks feed Rocky Mountain rivers and lakes with the water supply for onequarter of the United States. The rivers that flow from the Rocky Mountains eventually drain into three of the world's Oceans: the Atlantic Ocean, the Pacific Ocean, and the Arctic Ocean.[1] The Continental Divide is located in the Rocky Mountains and designates the line at which waters flow either to the Atlantic or Pacific Oceans. Triple Divide Peak (8,020 feet / 2,444 m) in Glacier National Park (U.S.) is so named because water that falls on the mountain reaches not only the Atlantic and Pacific, but Hudson Bay as well. Farther north in Alberta, the Athabasca and other rivers feed the basin of the Mackenzie River, which has its outlet on the Beaufort Sea of the Arctic Ocean. Human history Since the last great Ice Age, the Rocky Mountains were home first to Paleo-Indians and then to the indigenous peoples of the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Crow, Flathead, Shoshoni, Sioux, Ute, Kutenai (Ktunaxa in Canada), Sekani, Dunne-za, and others.[1] Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains. Like the modern tribes that followed them, Paleo-Indians probably migrated to the plains in fall and winter for bison and to the mountains in spring and summer for fish, deer, elk, roots, and berries. In Colorado, along the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400–5,800 years.[1] A growing body of scientific evidence indicates that indigenous peoples had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning.[1] Recent human history of the Rocky Mountains is one of more rapid change.[1] The Spanish explorer Francisco Vásquez de Coronado—with a group of soldiers, missionaries, and African slaves—marched into the Rocky Mountain region from the south in 1540. The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed the Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture.[1] In 1739, French fur traders Pierre and Paul Mallet, while journeying through the Great Plains, discovered a range of mountains at the headwaters of the Platte River, which local American Indian tribes called the "Rockies", becoming the first Europeans to report on this uncharted mountain range.[3] Sir Alexander MacKenzie (1764 – March 11, 1820) became the first European to cross the Rocky Mountains in 1793. He found the upper reaches of the Fraser River and reached the Pacific coast of what is now Canada on July 20 of that year, completing the first recorded transcontinental crossing of North America north of Mexico. He arrived at Bella Coola, British Columbia, where he first reached saltwater at South Bentinck Arm, an inlet of the Pacific Ocean. The Lewis and Clark Expedition (1804–1806) was the first scientific reconnaissance of the Rocky Mountains. Specimens were collected for contemporary botanists, zoologists, and geologists.[1] The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels.[1] Mountain men, primarily French, Spanish, and British, roamed the Rocky Mountains from 1720 to 1800 seeking mineral deposits and furs. The fur-trading North West Company established Rocky Mountain House as a trading post in what is now the Rocky Mountain Foothills of present-day Alberta in 1799, and their business rivals the Hudson's Bay Company established Acton House nearby. These posts served as bases for most European activity in the Canadian Rockies in the early 1800s. Among the most notable are the expeditions of David Thompson (explorer), who followed the Columbia River to the Pacific Ocean. On his 1811 expedition, he camped at the junction of the Columbia River and the Snake River and erected a pole and notice claiming the area for Great Britain and stating the intention of the North West Company to build a fort at the site. By the Anglo-American Convention of 1818, which established the 49th Parallel as the international boundary west from Lake of the Woods to the "Stony Mountains"; the UK and the USA agreed to what has since been described as "joint occupancy" of lands further west to the Pacific Ocean. Resolution of the territorial and treaty issues, the Oregon dispute, was deferred until a later time. In 1819, Spain ceded their rights north of the 42nd Parallel to the United States, though these rights did not include possession and also included obligations to Britain and Russia concerning their claims in the same region. After 1802, American fur traders and explorers ushered in the first widespread Caucasian presence in the Rockies south of the 49th parallel. The more famous of these include Americans included William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith. On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using Wyoming's South Pass.[1] Similarly, in the wake of Mackenzie's 1793 expedition, fur trading posts were established west of the Northern Rockies in a region of the northern Interior Plateau of British Columbia which came to be known as New Caledonia, beginning with Fort McLeod (today's community of McLeod Lake]] and Fort Fraser, but ultimately focussed on Stuart Lake Post (today's Fort St. James). Negotiations with Great Britain over the next few decades failed to settle upon a compromise boundary and the Oregon Dispute became important in geopolitical diplomacy between the British Empire and the new American Republic. Disputed joint-occupancy by Britain and the U.S.A., lasted until June 15, 1846, when Britain ceded their claims to this land with the Oregon Treaty. In 1841 James Sinclair, Chief Factor of the Hudson's Bay Company, guided some 200 settlers from the Red River Colony west to bolster settlement around Fort Vancouver in an attempt to retain the Columbia District for Britain. The party crossed the Rockies into the Columbia Valley, a region of the Rocky Mountain Trench near present-day Radium Hot Springs, British Columbia, then traveled south. Despite such efforts, in 1846, Britain ceded all claim to Columbia District lands south of the 49th parallel to the United States; as resolution to the Oregon boundary dispute by the Oregon Treaty. Thousands passed through the Rocky Mountains on the Oregon Trail beginning in 1842. The Mormons began to settle near the Great Salt Lake in 1847. From 1859 to 1864, Gold was discovered in Colorado, Idaho, Montana, and British Columbia sparking several gold rushes bringing thousands of prospectors and miners to explore every mountain and canyon and to create the Rocky Mountain's first major industry. The Idaho gold rush alone produced more gold than the California and Alaska gold rushes combined and was important in the financing of the Union Army during the American Civil War. The transcontinental railroad was completed in 1869, and Yellowstone National Park was established as the world's first national park in 1872. A transcontinental railroad in Canada was originally promised in 1871, but was not completed until until 1885 due to political reasons, but was eventually built via
the Kicking Horse Pass after consideration of a number of other routes. Thanks to the vision of the railway's promoters, vast areas of the Canadian Rockies were set aside as Jasper, Banff and Yoho National Parks, laying the foundation for a tourism industry which thrives to this day. Glacier National Park was established with a similar relationship to tourism promotions by the Northern Pacific Railroad. While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. U.S. President Harrison established several forest reserves in the Rocky Mountains in 1891–1892. In 1905, U.S. President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park.[1] Economic development began to center on mining, forestry, agriculture, and recreation, as well as on the service industries that support them.[1] Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities.[1] Industry and development Economic resources of the Rocky Mountains are varied and abundant. Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum, silver, tungsten, and zinc. The Wyoming Basin and several smaller areas contain significant reserves of coal, natural gas, oil shale, and petroleum. For example, the Climax mine, located near Leadville, Colorado, was the largest producer of Molybdenum in the world. Molybdenum is used in heat-resistant steel in such things as cars and planes. The Climax mine employed over 3,000 workers. The Coeur d’Alene mine of northern Idaho produces silver, lead, and zinc. Canada's largest coal mines are near Fernie, British Columbia and Sparwood, British Columbia; additional coal mines exist near Hinton, Alberta,[1] and in the Northern Rockies surrounding Tumbler Ridge, British Columbia. A drilling rig drills for natural gas just west of the Wind River Range in the Wyoming Rockies Abandoned mines with their wakes of mine tailings and toxic wastes dot the Rocky Mountain landscape. In one major example, eighty years of zinc mining profoundly polluted the river and bank near Eagle River in north-central Colorado. High concentrations of the metal carried by spring runoff harmed algae, moss, and trout populations. An economic analysis of mining effects at this site revealed declining property values, degraded water quality, and the loss of recreational opportunities. The analysis also revealed that cleanup of the river could yield $2.3 million in additional revenue from recreation. In 1983, the former owner of the zinc mine was sued by the Colorado Attorney General for the $4.8 million cleanup costs; five years later, ecological recovery was considerable.[1][4] Agriculture and forestry are major industries. Agriculture includes dryland and irrigated farming and livestock grazing. Livestock are frequently moved between high-elevation summer pastures and low-elevation winter pastures,[1] a practice known as transhumance. Human population is not very dense in the Rocky Mountains, with an average of four people per square kilometer (10 per square mile) and few cities with over 50,000 people. However, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The 40-year statewide increases in population range from 35% in Montana to about 150% in Utah and Colorado. The populations of several mountain towns and communities have doubled in the last 40 years. Jackson Hole, Wyoming, increased 260%, from 1,244 to 4,472 residents, in 40 years.[1] Tourism Every year the scenic areas and recreational opportunities of the Rocky Mountains draw millions of tourists.[1] The main language of the Rocky Mountains is English. But there are also linguistic pockets of Spanish and Native American languages. French is an official language in Canada's national parks. People from all over the world visit the sites to hike, camp, or engage in mountain sports.[1] In the summer season, the main[citation needed] tourist attractions are: In the United States:
• • • • • • •
Pikes Peak Royal Gorge Rocky Mountain National Park Yellowstone National Park Grand Teton National Park Glacier National Park (U.S.)
Sawtooth National Recreation Area In Canada, the mountain range contains these national parks:
• • • • •
Banff National Park Jasper National Park Kootenay National Park Waterton Lakes National Park
Yoho National Park Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other and collectively are known as Waterton-Glacier International Peace Park. (See also International Peace Park.) In the winter, skiing is the main attraction. A list of the major ski resorts can be found at List of U.S. Rocky Mountain ski resorts. The adjacent Columbia Mountains in British Columbia contain major resorts such as, Fernie, Panorama and Kicking Horse, as well as Mount Revelstoke National Park. There are numerous provincial parks in the British Columbia Rockies, the largest and most notable being Mount Assiniboine Provincial Park, Mount Robson Provincial Park, Northern Rocky Mountains Provincial Park, Kwadacha Wilderness Provincial Park, Stone Mountain Provincial Park and Muncho Lake Provincial Park. Climate The Rocky Mountains have a highland climate. The average annual temperature in the valley bottoms of the Colorado Rockies near the latitude of Boulder is 43 °F (6 °C). July is the hottest month there with an average temperature of 82 °F (28 °C). In January, the average monthly temperature is 7 °F (−14 °C), making it the region's coldest month. The average precipitation per year there is approximately 14 inches (360 mm). The summers in this area of the Rockies are warm and dry, because the western fronts impede the advancing of water-carrying storm systems. The average temperature in summer is 59 °F (15 °C) and the average precipitation is 5.9 inches (150 mm). Winter is usually wet and very cold, with an average temperature of 28 °F (−2 °C) and average snowfall of 11.4 inches (29.0 cm). In spring, the average temperature is 40 °F (4 °C) and the average precipitation is 4.2 inches (107 mm). And in the fall, the average precipitation is 2.6 inches (66 mm) and the average temperature is 44 °F (7 °C). Types of Mountains How are mountains formed? Mountains are formed by slow but gigantic movements of the earth's crust (the outer layer of the Earth). The Earth's crust is made up of 6 huge slabs called plates, which fit together like a jigsaw puzzle. When two slabs of the earth's crust smash into each other the land can be pushed upwards, forming mountains. Many of the greatest mountain ranges of the world have formed because of enormous collisions between continents. Did you know? Earthquakes occur when two plates pushing past each other cause a fracture in the Earth’s crust. Mountains form in different ways Sometimes the crust has folded and buckled, sometimes it breaks into huge blocks. In both cases, great areas of land are lifted upwards to form mountains. Other mountains are formed by the earth's crust rising into a dome, or by volcanic activity when the crust cracks open. What different types of Mountains are there? There are five basic kinds of mountains: 1. Fold Mountains (Folded Mountains) 2. Fault-block Mountains (Block Mountains) 3. Dome Mountains 4. Volcanic Mountains 5. Plateau Mountains These different types of mountain names not only distinguish the physical characteristics of the mountains, but also how they were formed.
Fold Mountains Fold mountains are the most common type of mountain. The world’s largest mountain ranges are fold mountains. These ranges were formed over millions of years. Fold mountains are formed when two plates collide head on, and their edges crumbled, much the same way as a piece of paper folds when pushed together. The upward folds are known as anticlines, and the downward folds are synclines. Examples of fold mountains include:
• Himalayan Mountains in Asia • the Alps in Europe • the Andes in South America • the Rockies in North America • the Urals in Russia The Himalayan Mountains were formed when India crashed into Asia and pushed up the tallest mountain range on the continents. In South America, the Andes Mountains were formed by the collision of the South American continental plate and the oceanic Pacific plate. Did you know? Two Tectonic Plates meet along the Southern Alps. This is called a fault line. The Southern Alps are constantly changing because the Pacific Plate is being pushed down under the Australian Plate and that causes the Alps to rise up.
Fault-block Mountains These mountains form when faults or cracks in the earth's crust force some materials or blocks of rock up and others down. Instead of the earth folding over, the earth's crust fractures (pulls apart). It breaks up into blocks or chunks. Sometimes these blocks of rock move up and down, as they move apart and blocks of rock end up being stacked on one another. Often fault-block mountains have a steep front side and a sloping back side. Examples of fault-block mountains include: • the Sierra Nevada mountains in North America • the Harz Mountains in Germany
Dome Mountains Dome mountains are the result of a great amount of melted rock (magna) pushing its way up under the earth crust. Without actually erupting onto the surface, the magma pushes up overlaying rock layers. At some point, the magma cools and forms hardened rock. The uplifted area created by rising magma is called a dome because of looking like the top half of a sphere (ball). The rock layers over the hardened magma are warped upward to form the dome. But the rock layers of the surrounding area remain flat. As the dome is higher than its surroundings, erosion by wind and rain occurs from the top. This results in a circular mountain range. Domes that have been worn away in places form many separate peaks called Dome Mountains.
Volcanic Mountains As the name suggests, volcanic mountains are formed by volcanoes. Volcanic Mountains are formed when molten rock (magma) deep within the earth, erupts, and piles upon the surface. Magna is called lava when it breaks through the earth's crust. When the ash and lava cools, it builds a cone of rock. Rock and lava pile up, layer on top of layer. Examples of volcanic mountains include: • Mount St. Helens in North America • Mount Pinatubo in the Philippines • Mount Kea and Mount Loa in Hawaii Find out more about volcanoes
Plateau Mountains (Erosion Mountains) Plateau mountains are not formed by internal activity. Instead, these mountains are formed by erosion. Plateaus are large flat areas that have been pushed above sea level by forces within the Earth, or have been formed by layers of lava. The dictionary describes these as large areas of ‘high levels’ of flat land, over 600 meters above sea level. Plateau mountains are often found near folded mountains. As years pass, streams and rivers erode valleys through the plateau, leaving mountains standing between the valleys. The mountains in New Zealand are examples of plateau mountains Mountain A mountain is a landform that extends above the surrounding terrain in a limited area. A mountain is generally higher and steeper than a hill, but there is considerable overlap, and usage often depends on local custom. Some authorities define a mountain as a peak with a topographic prominence over an arbitrary value: for example, the Encyclopædia Britannica requires a prominence of 2,000 feet (610 m). 24% of the Earth's land mass is mountainous; 10% of the world's 6 billion people live in mountainous regions. All the world's major rivers are fed from mountain sources, and more than
half of humanity depends on mountains for water [1]. The adjective montane is used to describe mountainous areas and the things associated with them. Mountain - Heights Heights of mountains are generally given as heights above mean sea level. The Himalayas average 5km above sea level, whilst the Andes average 4km. Most other mountain ranges average 2-2.5km. The highest mountain on Earth is Everest, 8850 m, set in the world's most significant mountain range, the Himalaya. Other definitions of height are possible. The peak that is farthest from the centre of the Earth is Chimborazo in Ecuador. At 6,272 m above sea level it is not even the tallest peak in the Andes, but because the Earth bulges at the equator and Chimborazo is very close to the equator, it is 2,150 m further away from the Earth's centre than Everest. The peak that rises farthest from its base is Mauna Kea on Hawaii, whose peak is over 9,000 m above its base on the floor of the Pacific Ocean. At 24 km, the tallest known mountain in the solar system is Olympus Mons, located on Mars. List of mountains, List of highest mountains, Latin names of mountains, Mountain range and list of mountain ranges, List of mountains on Venus, List of mountains on the Moon, Gallery of mountains, Peak Mountain - Characteristics The altitude of mountains means that the tops exist in higher cold layers of the atmosphere. They are consequently often subject to glaciation and erosion through frost action. This produces the classic mountain peak shape. Some mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3000 in Bhutan.
Sufficiently tall mountains have very different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes on their slopes. The plants and animals of a zone are somewhat isolated when the zones above and below are inhospitable, and many unique species occur on mountainsides as a result. Extreme cases are known as sky islands. Cloud forests are forests on mountain sides which attract moisture from the air, creating a unique ecosystem. Mountains are not generally favored for human habitation; the weather is harsher, less food is available, and there is little level ground suitable for farming. At very high altitudes, there is less oxygen in the air, and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3500 metres. Despite some biological adaptation by peoples who have lived on mountains for hundreds or thousands of years, babies' average birthweight is reduced by 100 grams for every 1000-metre gain in altitude. Most mountains of the world have been left in their natural state, and are today primarily used for recreation. Some mountains are very difficult to climb, and offer spectacular views. Some people therefore enjoy the sport of mountaineering. Mountains are also the site for the sport of downhill skiing. People engaging in these activities often stay at mountain resorts built for the purpose. Mountain - Geology A mountain is usually produced by the movement of lithospheric plates, either orogenic movement or epeirogenic movement. The compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upwards, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, a mountain. The absolute heights of features termed mountains and hills vary greatly according to an area's topography. The major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Mountain creation tends to occur in discrete periods, each referred to as an orogeny. The orogeny may last millions of years, and the uplifted region is being eroded away, producing valley-and-peak topography, even while the uplift is taking place. Two types of mountain are formed depending on how the rock reacts to the tectonic forces – block mountains or fold mountains. The compressional forces in continental collisions may cause the compressed region to thicken, so the upper surface is forced upwards. In order to balance the weight, much of the compressed rock is forced downwards, producing deep "mountain roots". Mountains therefore form downwards as well as upwards (see isostasy). However, in some continental collisions part of one continent may simply override part of the other, crumpling in the process. Some isolated mountains were produced by volcanoes, including many apparently small islands that reach a great height above the ocean floor. Block mountains are created when large areas are widely broken up by faults creating large vertical displacements. The uplifted blocks are block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley. Where rock does not fault it folds, either symmetrically or asymmetrically. The upfolds are anticlines and the downfolds are synclines; in asymmetric folding there may also be recumbent and overturned folds. The Jura mountains are an example of folding. Over time, erosion can bring about an inversion of relief: the soft upthrust rock is worn away so the anticlines are actually lower than the tougher, more compressed rock of the synclines. Mountain - Characteristics The altitude of mountains means that the tops exist in higher cold layers of the atmosphere. They are consequently often subject to glaciation and erosion through frost action. This produces the classic mountain peak shape. Some mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3000 in Bhutan. Sufficiently tall mountains have very different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes on their slopes. The plants and animals of a zone are somewhat isolated when the zones above and below are inhospitable, and many unique species occur on mountainsides as a result. Extreme cases are known as sky islands. Cloud forests are forests on mountain sides which attract moisture from the air, creating a unique ecosystem. Mountains are not generally favored for human habitation; the weather is harsher, less food is available, and there is little level ground suitable for farming. At very high altitudes, there is less oxygen in the air, and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3500 metres. Despite some biological adaptation by peoples who have lived on mountains for hundreds or thousands of years, babies' average birthweight is reduced by 100 grams for every 1000-metre gain in altitude. Most mountains of the world have been left in their natural state, and are today primarily used for recreation. Some mountains are very difficult to climb, and offer spectacular views. Some people therefore enjoy the sport of mountaineering. Mountains are also the site for the sport of downhill skiing. People engaging in these activities often stay at mountain resorts built for the purpose. How are Mountains Formed Mountains are formed due to the slow and gigantic movement of the Earth's crust. Read on to know more... Mountains are a type of landform that are characterized by a higher elevation, in comparison to the surrounding areas. They are higher than 600 meters, and taller and steeper than the hills. The world's tallest mountains are located in Asia and the largest range of mountains is present in the Atlantic ocean. Some of the highest mountain peaks are located in the oceans. Mountains represent varying climatic conditions based on their height (elevation). For example, in case of a tall mountain, the conditions at the base differ from the top of the mountain. In comparison to the mountain base, the top portion is more cold (presence of snow cover) and there is less oxygen and less protection from the sun's rays. Accordingly, the flora and fauna inhabiting the different zones vary. Forests present on the sides of the mountains are called alpine forests. It is estimated that half of the world population depends on mountains for water. In fact, the major rivers of the world are fed by mountains. Many mountains have glacial lakes that are formed due to melting of the glaciers. Let's take a look at the formation of mountains. How are Mountains Formed Mountains are made up of earth and rock materials. The outermost layer of the Earth or the Earth's crust is composed of six plates. When two plates move or collide each other, vast land areas are uplifted, resulting in the formation of mountains. Depending upon the geological process, as to how the mountains are formed and the mountain characteristics, there are five major types of mountains. Fold Mountains: Fold mountains are the most common type of mountains. Examples of fold mountains are the Himalayas (Asia), the Alps (Europe). They are formed due to collision of two plates, causing folding of the Earth's crust. The fold that descends on both sides is called anticline; whereas, the fold that ascends from a common low point (on both sides) is called syncline. Fault-Block Mountains: As the name suggests, fault mountains or fault-block mountains are formed when blocks of rock materials slide along faults in the Earth's crust. There are two types of block mountains, namely the lifted and tilted. In the former type, the mountain has two steep sides; whereas, the tilted type has one steep side and gentle sloping side. Example of fault-block mountain is the Sierra Nevada mountains (North America). Volcanic Mountains: Volcanic mountains are formed due to volcanic eruptions, for e.g. Mount Fuji (Japan). They are formed when volcanic magma erupts and piles up on the surface of the Earth. Dome Mountains: Dome mountains are formed when the hot magma rises from the mantle and uplifts the overlying sedimentary layer of the Earth's crust. In the process, the magma is not erupted, but it cools down and forms the core of the mountain. Example of dome mountain is the Navajo Mountain in Utah. They are called dome mountains due to their appearance that resembles dome shape. Plateau Mountains: Plateau mountains are pseudo mountains that are formed because of erosion. An example of plateau mountain is the Catskill Mountains (New York). They usually occur near the fold mountain ranges. There are also some mountains that are formed as a result of many forces of the Earth. Though the Rockies in North America is formed due to folding, there are mountains in the same range that are formed by faulting and doming. In nature, there is a continuous process of glaciation, soil erosion, and mechanical and chemical weathering, which altogether play a major role in altering the shape and characteristics of mountains.