Colliding Continent & Fold Mountains

CONTINENTS

The classic example of two continents colliding is the sub continent of India colliding with the continent of Asia. A European example can be found where Italy collided with the rest of Europe, now Switzerland and Austria.

Asia India

India has been steadily drifting North away from

Africa after PANGEA broke up.Mantle

As India moved towards Asia, the sea between the two land masses, called the Sea of Tethys had new layers of sediment laid down on the sea bed, brought by rivers flowing off the two continents

AsiaIndia

Rivers carry masses of sediment into the sea Sea of Tethys

India bulldozes the sea floor sediments up into folds, making the Sea of Tethys even shallower.

AsiaIndia

Sea get shallower as sediments builds up and is pushed into folds by

India acting like a bulldozer.

Descending plate re-melts in the upper mantle.

Gradually as the sediments get pushed even higher, the Sea of Tethys begins to disappear, leaving stranded salt lakes

AsiaIndia

Salt lakes

Layers of sediment get increasingly folded.

As the sea dries up, the salt lakes become the salt deposits of the future, trapped in fold

mountains.

Asia India

The sea has now gone, leaving a range of young

fold mountains.

The folding becomes more dramatic and complex as the fold mountains get higher.

AsiaIndia

Volcanic activity increases.

Asia India

The new range of mountains is called the Himalayas. They are entirely made from sedimentary and metamorphic rock.

Asia India

As the two continents collide, the destructive plate margin becomes inactive and volcanic activity almost stops. There is still some forward movement of the Indian plate, so the

Himalayas are still growing higher.

AsiaIndia

Eventually, some time in the future, a new destructive plate margin will form at the edge of the Indian Ocean.

Asia India

New plate margin forms under the Indian Ocean.

The next sequence of slides shows the process again,

without the labels.