what is the top layer of the earth?
a dry brittle surface of recently cooled lava
what are 3 points about the crust?
1) think rock layer at the surface
2) floats on the mantle
3) two types: oceanic and continental
4) continuously stressed (plate tectonics)
what is the difference between oceanic and continental crust?
oceanic:
- denser (heavier)
- younger
- mainly basalt
continental:
- less dense (lighter)
- older
- mainly granite
where is continental crust thickest?
under mountain ranges (20 - 60 km)
what are 3 facts about the mantle?
1) accounts for 80% of the Earth’s volume
2) temp ranges from 5000 to 1300
3) two parts: upper lithosphere + asthenosphere
what is the difference between the lithosphere and the asthenosphere?
lithosphere:
- more rigid
- cooler
- closer to crust
asthenosphere:
- semi molten
- next to core
what are the crust and mantle separated by?
moho discontinuity
what are 3 facts about the core?
1) outer core = semi molten
2) inner core = solid
3) temperature at centre is 5,500