Mountain
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A mountain is a natural rise of the earth's surface that usually has a "summit" (or "top"). It is usually steeper and taller than a hill. Mountains are often thought of as being a hill of over 600 metres (about 2,000 feet), but this definition is not the same in every country.
Mountains are important to the life of many things on the planet Earth, because nearly all the rivers begin in mountains and carry water from the mountains down to the flatter land where most people live.
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[change] What is a mountain?
- The highest point of a mountain is called the peak. A mountain's summit is the highest area an individual can reach. A mountain climber will not reach the peak of the mountain but can reach the summit.
- Britannica Student Encyclopedia says that the term "mountain' usually means a rise of over 2,000 feet (610 m)".[1].
- The standard height for a mountain in England is 600 metres. In England, it is important to have a legal height because people have the "Right to Roam" in mountains, but they do not have the same right to walk on someone-else's land. Even though mountains are defined by law, many people in England use the word "hill" even when they are talking about a very large mountain such as those in north India.
- In the USA, even though there are many very tall mountains, the name mountain is often given to hills that may be only 100 feet high.
- In Scotland, a mountain that is over 3,000 feet (914.4 m) is sometimes called a "Munro".
- In Australia and some other places, the word "mountains" is also used to describe high land that is really a plateau and is flat on top, rather than having peaks.
[change] Formation
Mountains are formed when rock layers are squeezed from opposite sides when forces within earth push up crust. Mountains also form when some rock blocks move up and others move down. They can be found in both water and land areas. A mountain range is a large group of mountains.
[change] Height
The height of a mountain is measured as distance above sea level. The tallness of a mountain is from the center.
[change] Tallest mountains
The highest mountain in the solar system is Olympus Mons (27 km) on Mars. The highest mountain in the world is Mount Everest (8,848m)which is in India in Asia. (The "tallest" mountain in the world is Mauna Kea, in Hawaii. The "height" of a mountain is measured from sea level, but the "tallness" of a mountain is measured from its base, even if under water.) The highest mountain in North America is Mount McKinley (6,194m) in Alaska in the USA. The highest in South America is Aconcagua (6,962m) in Argentina. For Africa, it is Kilimajaro (5,963m) of Tanzania. In Europe, the highest mountain is in Russia called Elbrus (5,633m). Antarctica's highest mountain is Vinsin Massiff (5,140m). In Oceania, a mountain called Puncak Jaya (5,030m) is the highest there. This particular mountain is in Papua New Guinea / Indonesia.
[change] Mountain types
There are four main mountain building processes:
- fault
- fold
- plutonic
- volcanic
There are five main types of mountains:
- volcanic
- domed
- folded
- plateau
- fault-block
Some people say there are six types, as domed mountains can be a plutonic dome or a tectonic dome.
[change] Volcanic mountains
Volcanic mountains are mountains that form when molten rock erupts onto the earth's surface. They can either form on land or in the ocean. The Cascade Range in Washington, Oregon and northern California is composed of volcanic mountains. Some of the largest volcanic mountains are found along divergent boundaries, which form the mid-ocean ridges. The mid-ocean ridges have huge volcanic mountain chains that run through the Atlantic, Pacific and Indian Oceans. The mountains in the mid-ocean ridges can actually grow tall enough to create islands such as Iceland or the Azores.
Other volcanic mountains can form over hot spots, which are pockets of magma beneath the crust that erupt onto earth's surface. The Hawaiian Islands are actually the tops of really high volcanic islands that have formed over a hot spot on the sea floor. The main Hawiian island is actually a volcano that is about 9 km above the ocean floor, with a base that is about 160 km wide. Almost 4 km of this island is above sea level. In fact, a new Hawaiian island is forming right now!
[change] Domed mountains
Domed mountains, like those in the Black Hills of South Dakota and the Adirondack Mountains of New York, are an unusual type of mountain that is formed when molten rock rises through the crust and push up the rock layers above it. This creates a circular dome on the earth's surface. The molten rock eventually cools off and forms hardened rock. When the pushed up rocks are worn away, the hardened rock exposed. This exposed rock then wears away in places, leaving separate high peaks, or dome mountains.
[change] Folded mountains
Folded mountains make up some of the highest mountains in the world. Folded mountains commonly form along converging boundaries, where 2 continents are colliding. They tend to look like an accordion. Some really complex folds can be found in parts of the Alps, Himalayas, Appalachians, and Russia's Ural Mountains. These long mountain chains also show extensive signs of folding.
[change] Plateau mountains
Plateau mountains are formed similar to folded mountains. They are large areas of flat topped rocks that have been lifted high above the crust by converging continental plates. Most plateaus are found near folded mountains. An example would be, the Tibetan Plateau, which is next to the Himalayan mountains.
[change] Fault block mountains
Fault block mountains are formed when parts of the earth's crust has been broken off into large ult block mountains are formed when two simultaneous blocks of land rise above or fall down leaving its middle part behind. when magma pushes up and forces top layers of rock (elastic) up with it. Domed mountains, although have broken (plasic) and move up as a 'chunk'. 5. 'M.O.R'- Mid Ocean Ridge, the area of sea floor spreading, lines of volcanoes.
A fault block mountain is a mountain or range formed as a horst when it was elevated between parallel normal faults. A horst is the raised fault block bounded by normal faults.
