Plate Tectonics

Oceanic crust

They are moving apart

Plates moving together

At a constructive plate margin the 2 plates move away from each other through convectional currents. Due to warm air rising boiling magma rises from the mantle and creates a mini-volcano filling the gap. This then cools and creates a new crust.

Think of this as the new-crust factory

Constructive, or divergent.

Because it's a destructive margin the two plates are slowly moving towards each other. When the oceanic plate meets the continental plate the denser oceanic plate is forced down and subducts under the other plate into the mantel and destroyed through friction. This often creates volcanos and an oceanic trench with the remains of the submerged plate.

The area where an oceanic plate is being pushed under a continental plate.

The plates are smashed together but no plates are destroyed because they're both pushing with the same force. Think of 2 cars colliding head on at the same speed.

2 oceanic plates come and push against each other. The pressure builds up and each plate folds upwards to make a mountain range. No volcanoes are created but light earthquakes are.

This is when 2 plates are sliding alongside each other in the same direction but at different speeds. Crusts aren't created or destroyed although this causes earthquakes.