Plate margins Flashcards
How and why do tectonic plates move
- Move towards one another - destructive/collision
- move apart from one another - constructive/divergent
- Slide past each other - conservative
What do destructive/convergent plates do
move towards one another
what do constructive/ divergent plates do
move apart from one another
What do conservative plates do
slide past one another
Describe collision plate boundary and give example
- type of convergent
- fold mountains are created
e.g alps
What is an example of a convergent/destructive plate boundary
Japan. 118 active volcanoes
Give an example of a divergent plate boundary
Mid Atlantic Ridge - Iceland
Give an example of a conservative plate boundary
San Andreas Fault line - USA
Explain convection currents
- Plates are continuously moving due to the convection currents in the mantle
- The core heats the molten rock in the mantle forcing it to rise
- When it approaches the crust cools down and descends
- This is known as a convection current
What is a hot spot
a stationary source of magma
Explain the physical processes that happen at a destructive plate boundary/ convergent
Japan is an example of a destructive plate margin, there are 118 active volcanoes. The dense oceanic plate subducts underneath the lighter continental plate. The oceanic plate subducts under gravity this is known as slab pull. the plate melts due to friction and a magma chamber is formed. The magma forces its way upwards causing a volcanic eruption. The release of energy in the form of seismic waves creates an earthquake
what is slab pull
older, denser tectonic plates sink into the mantle at subduction zones
what is ridge push
where the new crust formed at divergent is less dense than the surrounding crust and so it rises to form oceanic ridges.
Explain collision plate boundary
Collision is a type of convergent plate boundary. Two continental plates collide and are forced upwards creating fold mountains, subduction does not take place and therefore there is no volcanic eruption. An example is the Alps in Europe or the Himalays in Asia.
What do destructive plate margins create
Earthquakes (violent)
Composite volcanoes
Give example of a destructive plate margin
Pacific and Philippine plates
example of conservative plate margins
pacific and north american
describe conservative plate margin movement
pressure builds at the margin of the tectonic plates as they are pulled along behind a plate being subducted elsewhere
As friction is overcome, the rock fractures in an earthquake
what do conservative plate margins create
earthquakes
Describe constructive plate boundary
constructive plate margin
the plates move apart from one another. When this happens the magma from the mantle rises up to make (or construct) new land in the form of a shield volcano. The movement of the plates over the mantle can cause earthquakes and release of seismic energy
What do constructive plate boundaries create
earthquake and volcanoes
