Plate Tectonics

Plate Tectonics

The theory of plate tectonics is a recent concept which helps us to understand how land masses and ocean basins of the earth are arranged.

What are Plates?

These are large sections of the earth’s crust that are able to move.

What is the Continental Drift?

The theory that the earth was one big landmass called ‘Pangea’ before it split into two pieces, to the North ‘Laurasia’ and to the South ‘Gondwanna’.

Evidence to the Continental Drift

1) The rock formations of the boundaries of continents near each other were similar.

2) It looked like a jigsaw puzzle.

3) Look alike fossils on different continents.

Types of Plate Movements

Convergent, Divergent and Transform Plate Margins.

Divergent Plate Margin

When two plates are moving away from each other.

Sea Floor Spreading

When two plates move away from each other, magma from beneath the earth rises to the surface where it cools and hardens to form a new strip of land.

Convergent Plate Margin

When two plates move towards each other.

Collision Zone

When two plates of continental crusts of the same mass converge they form a collision zone where fold mountains are formed.

Subduction Zone

When an oceanic and continental plate of different masses converge.

Transform Plate Margin

When two plates move alongside each other.

Events Occuring at Plate Margins

1) Divergent: Earthquakes and Volcanic Eruptions

2) Convergent: Fold Mountains, Earthquakes and Volcanic Eruptions
3) Transform: Earthquakes

What is an Earthquake?

A sudden release of energy in the Earth's crust that creates seismic waves.

Features of an Earthquake

1) The Focus: Where the earthquake originates.

2) The Epicentre: Where the waves are the strongest.