The Theory of Plate Tectonics

Theory of Plate Tectonics

The lithosphere is broken into Tectonic Plates

• The lithosphere is made from the crust and the uppermost part of the mantle

• The lithosphere is rigid, brittle rock

• These plates float on the asthenosphere

Pangea

• The super continent that Alfred Wegener described in his theory of Continental Drift

How do the plates ACTUALLY MOVE?

• Convection currents in the asthenosphere drive the movement of lithospheric plates

How does a convection cell occur?

• Hot magma in the asthenosphere begins to rise, similar to the way hot air rises.

• As it rises to the top of the asthenosphere, it cools and becomes more dense.

• This cooler, dense magma then sinks again. As it sinks, it gets warmer, until the process begins again

• This movement of magma is what drives the plates to move.