What is tectonics? Tectonics is the study of the movement of the Earth’s crust. The slow movement of the mantle moves the crust which sits on top of it!

What would cause the Earth’s crust to break as it moves on top of the mantle? What do we call the broken pieces of Earth’s crust?

What is moving the plates? Convection

The lithosphere (the plates and upper mantle) move very slowly-- only a few cm. per year, as slow as your fingernails grow!

If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

Alfred Wegener came up with the theory of Continental Drift-- He thought that over millions of years the plates have moved so much, that once they must have been connected!

He called this connected supercontinent Pangea! Later, fossil evidence was found to prove how the continents once connected.

How can the plates move if they are completely covering Earth and all touching? They push each other out of the way!

Each Plate has it’s own name

There are four types of Plate Boundaries: 1.Divergent 2.Convergent 3.Subduction 4.Transform

Divergent Boundaries Two plates move apart and lava rises to fill the gap. New crust is formed. Causes oceanic ridges and rift valleys

Convergent Boundaries Two continental plates collide. Mountains are formed.

Subduction Boundaries An oceanic plate and continental plate collide. The oceanic plate is more dense, so it sinks underneath the continental plate. Volcanoes form where the collision occurs.

All around the Pacific Ocean plate, subduction causes volcanoes!

Transform Boundaries Two plates slide past each other This causes earthquakes