Jumat, 06 Juli 2007

Mountain range

Mountain range


A mountain range is a group of mountains bordered by lowlands or separated from other mountain ranges by passes or rivers. Individual mountains within the same mountain range do not necessarily have the same geology; they may be a mix of different orogeny, for example volcanoes, uplifted mountains or fold mountains and may, therefore, be of different rock.

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Tectonic plate movement

A range of mountains (often elongated) may be caused by tectonic plate interactions. For example, the Himalaya in Asia are the result of the Indian plate hitting the Eurasian plate, causing a 'crumple zone' near the line of impact. Sometimes, one tectonic plate can become pushed beneath another. The top plate scrapes off the material which builds up to form mountains, this happens over millions of years. Volcanoes can arise for this reason. An example is Vesuvius.

Volcanic action

Singular mountains are often the result of volcanic processes but, in some instances such as the Hawaiian Islands, these processes can result in a chain of mountains that might be considered a mountain range.

Erosion

Uplifted regions or volcanic caps can undergo erosion, resulting in a range of mountains. An example is the English Lake District(the english lake district is near the centre parks named whinfell forest). Mountain streams carry eroded debris downhill and deposit it in alluvial plains or in deltas. This forms the classical geological chain of events, leading to one type of sedimentary rock formation: erosion, transportation, deposition and compaction. it also has a lot to do with wathering and erosin that happens in the earth.

Climate

Mountains are one of the factors which influence climate. They very significantly affect rainfall. When wind moves over the sea, the warm moist air rises and cools to form orographic rainfall. Then the cool dry air moves over the ridge to the leeward side.

It also affects the temperature. If the sun is shining from the east, then the eastern side of the mountain will get the sun but the other side will be in shade.

Ecology

Mountain ranges can support different terrestrial biomes, at varying altitudes: at the bottom, they may have grassland, then a coniferous forest or boreal forest, then tundra at the top.

The Andes is the world's longest mountain range. The Himalaya contains the world's highest mountains.