Zusammenfassung der Ressource
Tectonics 1
- 1912: Alfred Wegener proposed Pangaea (continental drift)
- geological, climatological and biological evidence
- Africa and South America fit together
- similar fossil remains on each continent
- coal reserves in antartica
- which split into Gondwanaland and Laurasia
- Composition of the Earth
- Crust
- Oceanic
- heavier, denser, younger, non-permanent
- e.g Basalt
- Continental
- older, lighter, permanent
- e.g Granite
- Mantle
- Nickel and Iron
- 3,000km
- 1,000 degrees
- Outer Core
- Nickel and Iron
- Liquid = heat
- Inner Core
- Nickel and Iron
- Solid = pressure
- Convection currents
- 1000 degrees + mantle rocks are heated
- Rise up to cool surface
- They cool, go sideways and back down
- Ridge push
- Plates at spreading centres
- Hot material spews through gaps
- ridge formation
- as gravity pulls it down so more material flows out
- elevated temp lowes density so it rises in the mantle
- Slab Pull
- Plates at subduction zones
- lower temp makes plate denser than mantle
- the crust is pulled (subducted) into the mantle