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Mountains

Mountains And Humans

Transportation and communication are more difficult in mountains. Even today, mountain weather sometimes makes flying into mountains risky, and radio signals are blocked by the masses of stone. U.S. interstate highways close down due to snow, ice, and even rockfalls. The difficulty of operating in the mountainous countries of Afghanistan and Vietnam certainly affected the outcomes of the wars fought in those countries.

The thin, stony soil of mountain slopes possesses minimal value as farmland. Mountain meadows and forests provide a good pasture for grazing animals, however, and mountain people often practice pastoral agriculture. Herds of goats, cows, sheep, pigs, or llamas turn the upland vegetation directly into food and industrial products—wool, tallow, leather, and so on. But in order for farming and herding people to dwell in the mountains with any economic security, the population must remain low, to avoid using up all of the sparse resources.

Because of the difficulties mountains put in the way of making a living at agriculture, mountain regions usually cannot support a prosperous agricultural tax base. People of mountain cultures, therefore, are used to being left alone by governments. These peoples' independent outlook is interchangeable around the world, whether they are Swiss, Papuan, Appalachian, or Jamaican Maroon. Language and customs from hundreds or thousands of years ago survive in remote mountains, preserved by the same geography that cut them off in the first place.

Unlike farmers, people of the world's industrial civilization can find in the mountains a great bounty of the resources they cannot live without. Geologic formations of economically valuable minerals, called ore bodies, are left behind by the processes that make mountains. Mountain-building rearranges the formations that hold metal ores, coal, gemstones, asbestos, and other substances. These ore bodies come to rest near enough to the surface to be mined at a profit. Although many mining districts have been "mined out," this only means that the minerals that could be mined for a profit have been removed. The world's mountain ranges still contain vast amounts of economic minerals, out of sight under kilometers of rock. Present mining methods are too expensive to dig deep enough to process the great majority of them, however.

Broad, swift rivers drain mountains that receive large amounts of rain and snow. Dropping from the uplands, water rapidly accumulates kinetic energy (kinetic energy is the energy in a moving object). Hydroelectric power plants convert some of this energy into power, providing industries and cities with cheap, clean, and plentiful electric power. Mountainous Switzerland's hydroelectric power enabled it to become one of the world's leading industrial countries.

Resources

Books

Crump, D., ed. Mountain Worlds. Washington, DC: The National Geographic Society, 1988.

Keller, E.A. Introduction to Environmental Geology. 2nd ed. Upper Saddle River: Prentice Hall, 2002.

Press, F.,and R. Siever. Understanding Earth. 3rd ed. New York: W.H Freeman and Company, 2001.

Periodicals

George, U. "Tepuis-Venezuela's Islands in Time." National Geographic 175 (May 1989): 526-561.

KEY TERMS

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Collisional mountain belt

—A mountain range that is built when two or more continents run into each other.

Fault block mountains

—A mountain range formed by horizontal forces that squeeze a continent, fracturing its crust and pushing some crustal blocks upward to form mountains while others drop down to form valleys.

Island arc

—A string of volcanic mountains that emerge from the sea as islands.

Obduction

—A geological "accident" wherein a piece of the oceanic crust gets put on top of the continental crust, as opposed to beneath it as usual.

Ore body

—A geological formation in which an economically valuable mineral is concentrated.

Plate

—One of the pieces into which Earth's crust is broken, which floats on top of the mantle, and is pushed around by tectonic forces.

Shield volcano

—A broad, low profile volcano consisting of layers of basaltic rock, typically formed in the middle of oceanic plates or on continental rifts.

Stratovolcano

—A large, steepsided volcanic mountain, often located in an island chain (island arc) or on land in a series of volcanos along a tectonically active coast (continental arc).

Tectonic

—Having to do with forces that fold and fracture the rocks of planets.

Thrust fault

—A low-angle reverse fault in which the dip of the fault plane is 45° or less and displacement is primarily horizontal.

Thrust sheet

—A slab of the crust that gets pushed up on top of a neighboring slab of crust.

Topography

—The detailed surface features of an area.

Uplift

—An episode in the history of a region when tectonic forces lift the region's crust to a higher elevation.

Volcanic neck

—A usually tall, steep mountain of lava rock that solidified in the volcano's throat, stopping up the volcano as it became extinct.

Volcano

—A mountain that forms around a vent from which lava, ash, or other igneous rock is erupted.

Additional topics

Science EncyclopediaScience & Philosophy: Molecular distillation to My station and its duties:Mountains - Relative Size Of Mountains, Duration Of Mountains, Plate Tectonics, The Force That Builds Mountains - Types of mountains