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
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.
Where are Fold Mountains Made?
Fold Mountains
Alpine Fold Mountains
Alpine Fold Mountains
Alpine Fold Mountains
Alpine Fold Mountains
Which 2 plates collided to form the Andes?
The Himalayas
The Himalayas
The Himalayas
Which 2 plates collided to make 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