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Fold Mountains

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Fold Mountains Formation Form along both destructive and collision plate boundaries, in other words where two plates are pushing towards each other. – PowerPoint PPT presentation

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Title: Fold Mountains


1
Fold Mountains
2
Formation
  • Form along both destructive and collision plate
    boundaries, in other words where two plates are
    pushing towards each other.
  • The best examples are the Himalayas, the Rockies,
    the Andes and the Alps, all of which are huge
    fold mountain ranges caused by the collision of
    two plates.

3
Theory
  • The general theory is that as two plates, with
    land masses on them, move towards each other they
    push layers of accumulated sediment in the sea
    between them up into folds.
  • Thus most fold mountains will continue to grow,
    as the plates constantly move towards each other.

4
Fold Mountains Constructive Boundaries
5
Formation
  • As already seen, at a destructive plate boundary
    the oceanic plate is subducted beneath the
    continental one.
  • The molten material then rises to the surface to
    form volcanoes, either in an island arc (e.g. the
    West Indies) or on the continental land mass
    (e.g. the volcanoes of the Andes).
  • In both cases Fold Mountains can be formed.

6
Formation
  • When the Nazca plate dives under the South
    American one, their motion forward also has been
    pushing sediment together.
  • This, over millions of years, has been pushed up
    into huge fold mountains The Andes.
  • Within them there are also volcanoes as the
    mountains are above the subduction zone.

7
Formation
  • If an island arc has been formed, the same idea
    occurs.
  • Over millions of years the movement of the two
    plates together will push the island arc nearer
    to the continent.
  • As this occurs the sediments on the seabed are
    folded up to become huge mountains.

8
Fold Mountains Collision Margins
9
Formation
  • These occur less frequently, but two excellent
    examples are the Himalayas, where the Indian
    plate is moving North and East towards the
    stationary European plate, and the Alps, formed
    by the collision between the African and Eurasian
    plates.
  • In these examples both plates are Continental
    ones, and so can neither sink nor be destroyed.
  • The material between them is therefore forced
    upwards to form the mountains.

10
Formation
  • For the Himalayas the material that now forms the
    mountains was originally on the bottom of the
    non-existent Tethy's Sea.
  • As the Indian plate pushed towards the Eurasian
    one, the sediments were folded up to form the
    Himalayas, leaving the only trace of the sea to
    be the fossilised shells that you can find high
    up in the mountains.
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