Plate tectonics - created from Mind Map

Page 1

Replaced idea of continental drift

1950s and 1960s

7 large sections called plates

A few smaller sections called plates

Convection currents

Caused by the intense heat in the mantle

Causes the plates to move

Plate boundaries

Where two plates meet

Slow movement of the plates

Forms volcanoes and new mountains

Makes earthquakes and tsunamis

Constructive plate boundary

Where two plates are moving apart (diverging)

Hot magma from the mantle rises to fill the gap

When new magma continues to build up above the ocean

New crust is made

Creates new mountains under the sea

Mid oceanic ridge

New volcanic island are made

Destructive plate boundary

Two plates move together (continental and oceanic)

Earthquakes

Denser continental plate is forced down (subducted) underneath the less dense oceanic crust

creates an ocean trench and causes the material to melt as it is dragged down

The magma rises through cracks as a very violent volcano

Conservative plate boundary

Plates meet and slide past eachother

Faults are found here due to the plates moving in different directions

No crust is destroyed or added

Sliding movement is not smooth and immense friction builds up

Eventually one plate suddenly jerks past the other causing shockwaves and an earthquake on the surface

Collision plate boundary

Two continential plates bump into eachother

Both plates are continental so they buckle and fold

Pushes up the land to create fold mountains

Plate tectonics