Mountain Building (Important Facts) {Part-4}

THE PROCESS INVOLVED in mountain building - termed Orogenesis - occur as a result of the movement of the Earth's crustal plates. There are 3 main types of mountains:

1. Volcanic Mountains
2. Fold Mountains
3. Block Mountains

Volcanic Mountains

Fold Mountains

Block Mountains

Most Volcanic Mountains have been formed along plate boundaries where plates have come together or moved apart and lava and debris have been ejected onto the Earth's surface. The lava and debris may have built up to form a dome around the vent of a volcano.

Fold mountains are formed where plates push together and cause the rock to buckle upwards.

Where ocean crust meets less dense continental crust, the oceanic crust is forced under the continental crust. The continental crust is buckled by the impact.This is how folded mountain ranges, such as the Appalachian Mountains in North America, were formed.

Appalachian Mountains

Fold mountains are also formed where two areas of continental crust meet.The Himalayas, for example, began to form when India collided with Asia, buckling the sediments and parts of the oceanic crust between them.

Himalayas Formation

Block mountains are formed when a block of land is uplifted between two faults as a result of compression or tension in the Earth's crust. Often, the movement along faults has taken place gradually over millions of years. However, two plates may cause an earthquake by suddenly sliding past each other along a faultline.

Earthquakes