Fold Mountains

Mountains formed when two

Plates Collide.

Fold Mountains

• 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.

Fold Mountains

Formation of the Himalayas

Fold Mountains

Evidence 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 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 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 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.

Alpine Fold Mountains

Where are Fold Mountains Made?

Fold Mountains

Which two plates collided to form the Rockies?

Rockies in

N. America

Rockies

Which 2 plates collided to form the Andes?

Andes – S.

America

Andes

Alpine Fold Mountains

Which two plates collided to form the Alps?

Alpine Fold Mountains

Alpine Fold Mountains

Which 2 plates collided to make the Himalayas?

The Himalayas

The Himalayas

Himalayas

Mt.

Everest

The Himalayas

Armorican 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 Mountains

Caledonian Mountain Building Period

About 400 million years

ago, the Eurasian and

American Plates pushed

together.

The rocks that were

between these two

plates were pushed

up into mountains

In Ireland these mountains

existed from Galway to

Donegal to the Mourne

Mountains to the Dublin

and Wicklow Mountains

The mountains were

much higher than

they are now but

have been worn

down by millions of

years of weathering

Donegal

Mountains

Galway Mts

Wicklow Mts