Plate Tectonics What is it and what makes it work? Steven Earle, Geology Department Malaspina University-College

The Earth’s interior 7000 C 4000 C 1000 C

Pea-soup analogy

mantle convection Heat transfer from the core to the mantle produces slow convection of the mantle material (in the order of centimetres per year)

Mantle convection produces lateral forces at the boundary between the mantle and the crust

Lateral forces at the crust- mantle boundary push the crust around – in different directions – and this leads to the motion of crustal plates. The plates are moving at rates of cm/year

Plate motions

Divergent boundary

Convergent boundary Subduction

Transform boundary

Plates of the Earth’s crust

Plates around North America