Plate Boundaries.

The first 200 words of this essay...

Plate Boundaries

Divergent (constructive)

At Constructive margins such as the Mid-Atlantic Ridge two plates move away from each other. Molten rock which is magma immediately rises to fill any possible gaps and forms new oceanic crust. The Atlantic Ocean is widening by about 3cm a year which means that the Americas are moving away from Eurasia and Africa.

Later eruptions elsewhere in Iceland caused the temporary evacuation of Heimaey in 1973 and the melting of the part of the Vatnajokull ice cap in 1996.

Convergent (Destructive)

Destructive margins occur where the plates consisting of Oceanic crust move towards plates of Continental crust. To the west of South America the Nazca plate I move towards the American Plate. Where they meet the Nazca plate is forced downwards to form a subduction zone. A subduction zone is where the Nazca plate and the American plate meet as the move towards each other. Also a deep-sea trench is formed which in this case would be called the Peru-Chile trench. As the Oceanic crust descends, it melts due to the heat from the friction caused by the contact with the American Plate and also due to the