Tectonics Flashcards
Crust
Thinnest layer of Earth
Between 5 and 70km thick
Solid rock broken up into pieces called tectonic plates
Mantle
Thickest layer 2900km
Moves slow big circles caused by convection currents
1000 degrees near crust
3700 degrees near outer core
Semi-molten (semi-liquid rock)
Outer core
Semi liquid iron
3700 - 5000 degrees
2300km thick
Iron here is liquid and magnetic
Inner core
1250km thick
Hottest part of earth
5000 degrees
Made up or iron and nickel under pressure
Wegener’s theory
Jigsaw fit
All the countries of the world were once joined together and then had been moved apart
Called Pangea
Evidence for Continental Drift
Fossil evidence
Fossils found in countries so far away it would be impossible for the animal to get there unless all the countries of the World were connected
Convection currents
movements of volcanic rock in mantle
Palaeomagnetism
the study of the Earth’s magnetic field preserved in rocks
What are the tectonic plate
Pacific plate
North American plate
South American plate
Eurasion plate
Cocos plate
African plate
Nazca plate
Indo-australian plate
Juan de Fuca playe
Subduction zone
where one plate is forced downwards below another plate and grinds past it causing huge amounts of friction and heat
Destructive plate boundary
where two plates are moving towards each other
continental crust | oceanic crust
Fold mountains
large mountain ranges formed by the collision and ‘folding’ of two plates as they plates continually push into one another.
Ocean trench
a particularly deep point of the ocean bed where the oceanic and continental crust have dragged each other downwards
Plate boundary
where two very large crustal plates meet on the earth’s surface
Oceanic crust
plate that is made up of more dense rock
Composite volcano
A very steep volcano formed at a destructive boundary
Why earthquakes are often found at plate boundaries
Most earthquakes occur due to the movement and interaction of tectonic plates
Tectonic plates constantly shift and collide with one another creating eargtquakes at their boundaries