Fold Mountains Mountains formed when two Plates Collide.

Fold MountainsFold Mountains

Mountains formed when two Mountains formed when two Plates Collide.Plates Collide.


• Fold mountains are mountains that are made when two of the earth’s plates collide.

• When two plates collide the pressure compresses the rocks, forcing them to buckle and fold. Think of what happens to the bonnet of a car during a crash.

Evidence of FoldingEvidence of Folding

• Scientists have found fossils of dead sea creatures thousands of metres up in the Andes in South America.

• These creatures lived in the sea, and their remains sank to the ocean floor when they died.

• Their remains were trapped in newly forming rocks which are later pushed up from under the sea when plates collide to make fold mountains.

Ridge and Valley LandscapeRidge and Valley Landscape

• When the two plates collide the crust buckles and folds. This creates a pattern of ridges and valleys.

• The downward part (the valley) is called a syncline.

• The upward part (the ridge) is called an anticline.

Young Fold MountainsYoung Fold Mountains

• As we know from previous sections, the earth’s plates are constantly colliding in different parts of the world. These collisions are still increasing the height of some fold mountains today.

• The world’s young fold mountains are already about 30-35 million years old.

• These mountains are called Alpine Fold Mountains. They are very high because they have not been worn down by weathering and erosion.

Alpine Fold MountainsAlpine Fold Mountains

• There are 4 major mountain ranges formed during the Alpine Folding period. These are,

• 1. The Rockies in North America.

• 2. The Andes in South America.

• 3. The Alps in Europe.

• 4. The Himalayas in Asia.

Where are Fold Mountains Made?Where are Fold Mountains Made?

Alpine Fold MountainsAlpine Fold Mountains

Which 2 plates collided to form the Andes?Which 2 plates collided to form the Andes?

The HimalayasThe Himalayas

Which 2 plates collided to make the Himalayas?Which 2 plates collided to make the Himalayas?

Armorican Fold MountainsArmorican Fold Mountains• Ireland’s fold mountains were formed hundreds of

millions of years ago.

• They were formed in Munster about 250 million years ago, and were once as high as the Alps.

• However, weathering and erosion have worn them down over millions of years and they are now much smaller.

• Examples include the Magillicuddy’s Reeks, The Galtees, The Comeraghs, and The Knockmealdowns.

Armorican Fold MountainsArmorican Fold Mountains

Fold Mountains Mountains formed when two Plates Collide.

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