The Earth’s tectonic
There are two types of crust: -
Oceanic crust – denser and about 5km thick.
Continental crust – lighter and about 30km thick.
The crust is made up of individual
plates. These plates are constantly
moving due to the hot convection
currents that rise within the mantle.
The movement of the plates has a great
impact on the boundaries of the plates,
but the middle area of the plates are
Large convection systems in
the mantle may carry along
the plates of the lithosphere
like a conveyor belt.
Plates may move apart, move closer
together or slide past each other. This
may result in: -
•Deep ocean trenches
Exercise – name
Types of Plates
Compressional (destructive) plate
•Plates move together
•One plate sinks below the other
•The plate melts in the subduction
zone where there is great pressure
•Energy may be released as an
•The molten rock or magma may
rise forming composite volcanoes
•The lighter crust at the surface
may crumple to form fold
Tensional (constructive) plate boundaries
• Plates move apart
• Gap filled by rising
magma from the mantle
• Rising magma forms
• Most common under
oceans so submarine
volcanoes or volcanic
• Plates buckle to form
Passive (conservative) plate boundaries
• Plates slide past each
• May slide past each
other the same
direction ( and
different speeds) or
the opposite direction.
• Pressure builds up
until one plate gives
way causing an
• Can cause land to be
crumpled or ridged
• E.G. North American
Plate/Pacific Plate –
San Andreas Fault.
1. What is the likelihood of tectonic activity in the UK?
2. Tectonic activity in Europe is concentrated in Iceland
and southern Italy. State one tectonic similarity and
one difference between Iceland and Italy.
3. Type of Examples Features Example
plate of plates produced country/regi