Plate Tectonics:

Theory

Vocabulary: plate tectonics, plates, lithosphere, asthenosphere, divergent boundary, convergent boundary, subduction zone, transform boundary (fault), convection current

Plate Tectonics and Plates:

Lithosphere and Asthenosphere:

Divergent Boundary

Convergent Boundary:

3 types of Plate Boundaries:

Subduction zone:

:

Possible Causes:

Convection Currents

Convection Currents

The mantle is made of much denser, thicker material, because of this the plates "float" on it like oil floats on water.

Many geologists believe that the mantle "flows" because of convection currents. Convection currents are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over. The next time you heat anything like soup or pudding in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the mantle they also move the crust. The crust gets a free ride with these currents. A conveyor belt in a factory moves boxes like the convection currents in the mantle moves the plates of the Earth.