Plate Tectonics
- Created by: saoirse: )
- Created on: 11-01-17 17:50
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- Plate Tectonics
- Core (approx. 2000km thick)
- Inner Core- solid ball containing lots of iron and nickle
- Outer Core- semi molten ball containing lots of iron and nickle
- Mantle (approx. 3000km thick)
- Made of silicate rocks
- Near the core the mantle is quite rigid
- Above that there is the ASTHENOSPHERE which is semi molten and flows
- Very top is ridgid
- Crust
- The rigid top part of the mantle and the crust together are called the LITHOSPHERE
- Lithosphere is divided into slabs called tectonic plates
- Move due to convection currents in the asthenosphere
- Plates meet at boundaries or plate margins
- Move due to convection currents in the asthenosphere
- Lithosphere is divided into slabs called tectonic plates
- Continental crust is thicker and less dense (30-70km thick)
- Oceanic crust is thinner and more dense (6-10km thick)
- The rigid top part of the mantle and the crust together are called the LITHOSPHERE
- Movement of Tectonic Plates due to convection currents
- Radioactive decay of some elements in the mantle and core generates a lot of heat
- When the lower parts of the asthenosphere heats up they become less dense and slowly rise
- As they move towards the top they cool down and become more dense so they slowly sink
- These circular movements of semi-molten rock are called convection currents
- Convection currents create drag on the base of the tectonic plates and this causes them to move
- Creating Crust
- Rising convection currents diverge at the base of the lithosphere this causes the plates to move apart too
- Magma rises up then cools to form a new crust
- Over time this crust is dragged apart and more new crust forms
- When this happens at a plate margin under the sea the sea floor gets wider - sea floor spreading
- it creates structures called mid-ocean ridges
- Core (approx. 2000km thick)
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