What are Fold Mountains?

Image Credit: 
Main Image: 
Fold Mountains

You can easily distinguish between other types of mountains and the Fold Mountains as these mountains display folded elevations on large scale. The lateral compressions and the simultaneously uplifted stratified and sedimentary rocks give these mountains a crumpled like look resembling a carpet when it is pushed. Basically, these folds are formed because there is deformation in rocks. Depending upon the characteristics of rocks the edges of continental plates are made up of (brittle or ductile), the folds are formed. Hence, the various shapes in Fold Mountains are formed due to formation of different types of folds viz. symmetrical, asymmetrical, isoclincal, overturned, Chevron and recumbant folds.  



What are Fold Mountains?

Fold Mountains are formed when two tectonic plates collide with each other and the edges of these two plates merge into each other due to the push force that is created. In this way, the tectonic plates keep colliding with each other in a slow motion giving rise to long stretches of mountain ranges and peaks. Fold Mountains are mostly made up of sedimentary rocks. When a water body comes in between the two plates, the sedimentary deposits are forced to move in the depressions known as geosynclines. These deposits slowly form sedimentary rocks. When separated tectonic plates move towards each other, these sedimentary rocks wrinkle just as a cloth gets crumpled when pushed with force and rise up to form Fold Mountains. Fold Mountains can be classified as young fold mountains and old fold mountains. 

  • Young Fold mountains that are 10 to 25 millions years of age, Ex: Himalayas and Rockies
  • Old Fold mountains that are more than 200 millions years of age Ex: Appalachians and Urals in USA



What are the examples of other  kinds of Mountains?

There are other kinds of mountain formations as well. These are the

  • Volcanic mountains: Hawaiian Islands, Bermuda are the tops of Volcanic mountains, Cascade Mountain range in Washington
  • Fault Black mountains: Sierra Nevada Mountains in Nevada state of USA, Harz Mountains in Germany
  • Dome mountains  or Erosion mountains: Black Hills of South Dakota which are formed due to erosion
  • Plateau mountains: Adirondack Mountains in New York, Catskill mountains,  mountains of New Zealand



What is an Orogenic Event?

The Earth consists of two types of crusts viz. oceanic crust and continental crust. Orogenic events take place on both these crusts. The movement of tectonic plates is very slow and they only shift few centimeters in a year. Due to this, Fold Mountains take millions of years to rise to their actual height. This process of overlapping and collision of tectonic plates of the earth’s crust is known as "orogenic event". The Himalayas are still growing because the orogenic event between the Indian continental plate and the Eurasian continental plate has not stopped. Many times orogeny can occur in between two oceanic plates or between tectonic and oceanic plates. The Southern Alps in New Zealand are formed due to the collision between the Australian plate and Pacific plate.


Where are  Fold Mountains found?

Some famous examples of Fold Mountains are the, 

  • Andes
  • Rockies in North America 
  • Alps in Europe
  • Himalayas in the Indian subcontinent
  • Urals and Appalachians in USA

Himalayas are the youngest and tallest Fold Mountains in the world. The Himalayas are still growing and the process is thought to have started around 24 million years back when the Indian subcontinent plate collided with the Asian plate.


Do you know : While the Apallachians are older then the Himalayas and much smaller than them, what most of us might not know is that the Appalachians were higher than the Himalayas at one point in time, a time when the Eurasian and North American plates collided.

Do you know : 14 highest mountains of the world are in the Himalayas



For more information on Mountains, click on the links below: 

Alps are Fold mountains 

Volcanic Cones

External References
Related Videos: 
See video
Related Images: