What are mountains & how are they formed?
A mountain is a geological
landform that rises above the surrounding land. Mountains result from the
collision and friction between tectonic plants in the Earth's crust, or between
sub-plates, components of the plates. Tectonic plates move very slowly. It can
take millions and millions of years for mountains to form. The Himalayan
mountains began forming this way about 55 million years ago. The Himalayan
mountain range has 30 of the world’s tallest mountains, including Mount
Everest, which soars 29,035 feet in the air.
Types of mountains:
Mountains can be classified into five different basic types
based on the cause that formed the mountain, type of rocks, shape and placement
on land.
Fold Mountains (Folded Mountains): These are the most common types
of mountains. These are formed when two continental tectonic plates collide and
their edges crumble to form mountains. Folded mountains are the product of two intercontinental
(continent-continent) plate collisions. The crust is uplifted forming folds on
top of the other. Vast mountain ranges stretching across thousands of
kilometers are Fold Mountains. The Rocky Mountains in North America, the Alps
in Europe, the Andes in South America, the Urals in Russia and the Himalayan
Mountains in Asia are examples of Fold Mountains.
The Fold Mountains
are of two types:
New or Young Fold Mountains - The Alps, the Himalayas, the
Circum-Pacific oceanic mountains, etc., are worth mentioning. The main characteristics
of these mountains are the complex folding of the rocks, faulting, Volcanic,
activities, cordillera form, the erosion and weathering caused by running
water, ice, winds, etc., the existence of glacier-capped high peaks, etc.
Old Fold Mountains - These mountains were folded in very ancient
times. They were, then, subjected to denudation and uplift, many faults were
formed and the layers of the rock were wrapped. Many mountains exist as relics,
due to erosion. The presence of monad rocks, accordant summits, sculptured
domes, the irregular forms of peaks, relics plateaus, etc., are some of the
important characteristics of these mountains.
Fault-block Mountains (Block Mountains): Fault block mountains are
formed as a result of a combination of tension(tensional stress) and uplift
forces. The stretching and cracking of
the crust gives the mountains their appearance and name. They are bounded by
high‐angle normal faults, and usually form a series of horsts and grabens.
Broad crustal uplift (possibly a result of subduction stresses or mantle
upwelling) can stretch and break the crust, creating fault zones along which
the blocks move or slide. Uneven tectonic uplift can tilt the blocks.
Dome Mountains: Dome
mountains are rounded isolated structures that are usually not associated with
mountain belts as they occur in generally flat regions.
Volcanic Mountains: These mountains are the accumulations of large
amounts of volcanic lavas and pyroclastic material around the volcanic vent,
such as seamounts and stratovolcanoes. The Hawaiian and Aleutian Islands are
volcanic mountains.
Relict or Residual Mountains - The mountains which are subjected to
weathering and erosion for a long time, are lowered down and are called Relief
or Residual mountains. The mountains of the Western Ghats, the Aravalli
Mountain and the Parasnath mountain of Bihar belong to this type.
Lacolith Mountains - The outrushing magma forms the fissures, the
crust of the earth at a place into a dome, mountains formed in such a way are
called Lacolith Mountains.
Types of Mountains with Examples
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1.
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Block Mountain
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Ruwenzori Mountain range in Central Africa, Black forest, Vosges,
bohemian massif and the Sierra Nevada in the south-western USA.
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2.
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Fold Mountains
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Himalayas, Aravalli, Appalachians, Alps, Rockies, Andes.
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3.
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Relict Mountains
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Aravalli, Rajmahal, Nilgiris, Satpuras, Western Ghats.
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4.
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Dome Mountain
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Henry mountain, USA
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Also Read:
- Mountain Passes in Western and Eastern Ghats India
- Mountain Passes in Himalayas : India
- Mountains of the World - Continent Wise
- Major Straits of the world with Map
- Canals of the World - World Geography
- 75 Cities Towns on River Banks of India
- Land Locked Countries of the World - Continent Wise
- 20- Major Lakes of the World
- 16-Major Trenches of the World & Their Importance
- Volcanoes of the World - Continent Wise
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