1. Chapter 5 Deformation of the Crust
Mountain Formation

2. Individual mountains are parts of mountain ranges.
Adjacent mountain ranges make up a mountain system.
The largest mountain systems are part of two even larger systems called mountain belts….the circum-Pacific belt, and the Eurasian-Melanesian belt.

3. Plate Tectonics and Mountains
Both mountain belts are along convergent plate boundaries…believed to be responsible for most mountain formation.
Some mountain ranges may have formed where now inactive plate boundaries may have collided in the past…Appalachians.

4. Continental—Oceanic Collisions
Subduction causes the continental crust to be pushed up to form mountains.
Melting rock creates magma which rises to the surface, forming volcanoes.
Example…The Cascade mountain range in the Pacific Northwest.

5. Oceanic—Oceanic Collisions
Subduction causes melting of rock. Magma pushes up through the crust to form underwater volcanoes.
A volcanic island arc is the result. The Mariana Islands in the North Pacific Ocean are the peaks of volcanic mountains that rose above sea level.

6. Continental—Continental Collisions
No subduction. When continental crust collides, it is pushed upward to form high folded mountains.
The rock layers are squeezed together like an accordian.
Example…the Himalayas.

7. Plateaus
Large areas of flat-topped rock lifted high above sea level. Found next to folded mountains.
The rock layers are pushed upward slowly and gently enough that they remain flat instead of deforming and folding into mountains.