As we saw in the previous post ‘Plate Movement‘, the Earth’s crust is made up of tectonic plates which are constantly moving due to convection currents in the mantle.
Where two plates meet is called a plate boundary. There is a number of different types of plate boundaries.
Destructive Plate Boundary
A destructive plate boundary is sometimes called a convergent or tensional plate margin. This occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface.
Collision zones
Collision zones form when two continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains.
Constructive plate boundary
A constructive plate boundary, sometimes called a divergent plate margin, occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.
Plate movements are small and slow, but the effects can be huge.
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