The Development Of Pate Tectonic Theory

Question 1

How is the earth structured?

Answer 1

Lithosphere;
Crust: continental= 30-70km lower density granite
            Oceanic= 6-10km higher density basalt
Astentospheare;
Upper mantle= partially melted
Core;
Outer core=2200km liquid
Inner core=1270km solid

Question 2

Convection currents

Answer 2

[=plate=]*[=plate=] [=plate=]
↑→→→↓←←←↑ ↑→→→↓
↑ ↓ ↑ ↑ ↓
↑ ↓ ↑ ↑ ↓
↑ ↓ ↑ ↑ ↓
Heat Heat

These currents are in the liquid mantel and push plates when they move from the heat source causing some gaps and some collisions

Question 3

Ridge push

Answer 3

In mid ocean ridges very hot magma is pushed out. As this is got it is less dense and quite buoyant it rises over the ridge. As it cools it becomes denser and sinks whilst pulling out some extra magma with it. This is better understood by the phrase gravitational sliding.

Question 4

Slab pull

Answer 4

At a subduction boundary when the subducted plate is in hold of the magma it is pulled in by the magma and pulls with it more of the plate.