Tectonics: Plate tectonics

Before looking at plate tectonics we should first consider the structure of the earth. In the centre is a solid core. Surrounding the core is the inner core, then the mantle, which is covered in the earths 'skin' or crust.

The temperature of the earth reduces from the core (hottest) to the mantle and then the crust that is either continental crust (carrying earth) or oceanic (carrying water). The crust is made up from plates. the plates move with via the convection currents cause by the radioactive break down of the earths core. This movement is called Plate tectonics . It is plate tectonics that cause the creation of volcano's and earthquakes at a point where the plates meet. the diagram below shows the earth plates.

The plates have moved over many millions of years to form the continents as they currently exist.
The Earth's plates move in different directions

Plates behave differently at different plate boundaries:
1. At a tensional, constructive or divergent boundary the plates move apart.
2. At a compressional, destructive or convergent boundary the plates move towards each other.
3. At a conservative or transform boundary the plates slide past each other.

Tensional/Constructive Margins plate boundaries occur when two plates move away from each other. This allows magma to come to the surface, which hardens into ingenious rock. This can occur over a long period of time but eventually a volcano can develop.

At a compressional or destructive boundary the plates are moving towards each other. This usually involves a continental plate and an oceanic plate. t occurs when a occur when an oceanic plate is forced under (or subducts) a continental plate. as the plates are pushed together they are force upwards causing fold mountains, such as the Alps in Europe.




Conservative (transform faults) plate boundaries occur when two plates slide past each other.






Collision plate boundaries Collision plate boundaries occur when two continental plates move towards each other.





The movement of tectonic plates creates dramatic volcanic eruptions and earthquakes over which the human world has no control, although attempts have been made to manage the effects obviously not the causes.