Plate tectnotics and the forces at work at plate boundaries

Question 1

Intro - theory of plate tectonics

Answer 1

The theory of plate tectonics states that the Earth lithosphere is split into sections called plates.
These plates are moved by endogenic forces, such as conventions currents.
The magma, rises in the mantle.
As it rises, it cools, moves sideways and sinks downward.
This causes the plates to crash into each other or move away from each other.
This can create Earthquakes and Volcanoes.

Question 2

Part 1 - Convergant boundaries

Answer 2

There are three types of boundary:
Convergent,
Divergent and
passive.
Convergent boundaries crash into each other, which can cause powerful earthquakes.
There are three types of convergant boundaries,
Oceanic-oceanic, Continental-Continental and Oceanic-Continental

Question 3

Part two - Divergent Boundaries

Answer 3

Divergent boundaries pull away from each other.
An example of this boundary is the mid-Atlantic ridge, in the middle of Iceland.
Two plates pull apart and the magma from the mantle rises upwards and cool to create new land.
Rocks like basalt are found at these ridges.

Rift valleys are also created at divergent boundaries.
This is an example of a normal fault which occur when divergent boundaries pull apart.
As the crust pulls apart, it gets thinner.
Eventually the rocks fractures and breaks.
As it does so, the hanging wall falls down due to gravity and leaves the football elevated above it.
This is a rift valley, also known as a graben.

Question 4

Part 3 - passive boundaries

Answer 4

Passive boundaries are when two plates slide alongside each other.
These plates generate powerful earthquakes.
A piece of rock can jut out from each boundary and the two plates get caught.
Pressure builds up and the two rocks break.
The plate slides forward quickly, causing a violent earthquakes.
An example of this boundary is the San Andrea Fault.