1. 17.3 Theory of Plate Tectonics

2. Plate Tectonics
The theory of plate tectonics states that the Earth’s crust and rigid upper mantle are broken into enormous slabs called plates
These plates move in different directions and different rates

6. Plate Boundaries Tectonic plates interact plate boundaries
At some they come together, or converge
Others they move away from one another, or diverge
Some move horizontally to one another

8. Convergent

9. Divergent These are place where plates are moving apart
Most of these are found ion ocean floors where they form ocean ridges
This is where the ocean floor spreads
Scientists have measured the rate of growth of the Atlantic to be 2-3 cm/y
These boundaries can also occur on land and they are called rift valleys
East Africa

12. Transform