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Explaining plate collisions
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1.
Explain how volcanoes form
over hot-spot (4 marks)
As hotspots are areas of unusually hot magma in the lithosphere, this burns through the plate. Then,
Magma raises to the surface and creates a volcano. The volcanoes move with the plate. When they move
away from the hot-spot, they become extinct.
2.
Explain the processes that
happen at a conservative
plate margin (4 marks)
When 2 plates slide past each other, they tend to get stuck. This will build pressure and will be released
in a 'jerk' movement. This will cause an earthquake. There are no volcanic activity as no crust is
destroyed so magma can't rise.
3.
Explain the processes that
happen at a convergent
plate boundary on a
collision margin (4 marks)
Whenever 2 continental plates collide due to convection currents, no subduction occurs because the
plates are equally dense. Instead, folding, faulting and uplift leads to the formation of mountains due to
low density rock e.g. Himalayas
4.
Explain the processes that
happen at a convergent
plate boundary on a
destructive margin
This is when a denser oceanic plate is subducted underneath a continental plate because the oceanic
plate is more dense. In addition, the molten rock from the oceanic plate rises and it rises into the volcano
as magma is denser in the lithospheric mantle.
5.
Explain the processes that
take place at divergent plate
boundaries (4 marks)
Convection currents force 2 oceanic plates to move away from each other. Magma rises up to fill the gap
to form a mid-oceanic ridge and volcanic islands from basaltic oceanic crust due to convection currents.
This results in shield volcanoes which produces slow lava as the magma doesn't rise up with the same
pressure of a destructive plate margin.