Geography Revision Flashcards
What does the structure of the earth contain
Inner core
Outer core
Mantle
Crust
What is the mantle
This is the thickest layer of the earth and the second layer from the crust. It creates convection currents and is made of solid rock that can flow, plastic rock.
What is the inner core
The inner most part of the earth. It is 1200km thick from 6300km deep to 5100km. It is the hottest part of the earth- temperatures reach over 5500 degrees C. Mainly made of iron and nickel, the material is under lots of pressure. The rock is solid in the inner core due to the pressure.
What is the outer core
The outer core is found surrounding the core. It is a semi liquid iron. Temperatures are about 5300 degrees C. It is 2200 km thick. The liquid iron is what gives the earth the magnetic field which protects us from harmful solar winds and life on our planet.
What is the crust
The crust is the thinnest layer of the earth which is between 8 and 40km thick. The crust is the outer layer of the earth. It contains rocks and minerals. Its thinner under the ocean than on land.
What is destructive plate boundary
Where two plates are moving towards each other. One plate is continental crust and one is made of oceanic crust.
What is a plate boundary
Where two very large plates on the earths crust meet. Earthquakes and volcanoes happen here.
What is continental crust
This is a plate that makes up our land surfaces. It is made up of less dense rock and because of this, it doesn’t sink.
What is oceanic crust
This is a plate that makes up our oceans floors. It is made up of more dense rock. It sinks easily due to its density.
What is subduction zone
Where one plate is forced downwards below another plate and grinds past it causing huge amounts of friction and heat.
What is ocean trench
A particularly deep point of the ocean bed where the oceanic and continental crust have dragged each other downwards.
What are fold mountains
They are large mountain ranges formed by the collision and ‘folding’ of two plates as the plates continually push into one another.
What is pyroclastic flow
A superheated mass of rock, ash, gas and dust which moves at over 450mph at a temperature of about 1,000 degrees C.
