Global distribution of fold mountains

folding

Lithosphere

Large rigid sections called plates.

7 major & 7 minor plates

Theory of Continental Drift - how do they move

(movement of plates)

Forceful convection currents occur in the Earth’s mantle

What is a result of plate movement

Fold mountains.

destructive (convergent) plate boundaries

Plates meet at boundaries.

fold mountains occur here.

Form because of the immense pressure of the collision.

How do fold mountains occur

the pressure of the collision (destructive plate boundary) cause the plates to buckle upwards creating the fold mountain.

3 Mountain building periods

1. The Caledonian Orogeny

(Mountain building period) occurred approx 490-390MYA (million years ago).

• American & Eurasian plates

• Bluestack & Wicklow

As a result;

The folding has a SW-NE trend

Mainly located in north-western and Leinster regions of Ireland.

Oldest mountains in Ireland.

2. The Armorican Orogeny

Approx 250MYA

African & Eurasian plates collided

• Gave rise to ridge and valley landscapes of Munster.

• e.g. Macgillycuddy Reeks & the Galtees

3. The Alpine Orogeny

This folding occurred approx 30MYA

Did not affect Ireland

African and Indian plates collided w/ Eurasian plate

• Alps, Himalayas and Rocky mountains.

• Youngest fold mountains

• These peaks are some of the highest as

  denudation has not significantly affected their peaks.