The Theory of Plate Tectonics

Chapter 6 Lesson 3

Plate Tectonics

• Earth’s surface is made of rigid slabs of rock, or plate, that move with respect to each other.

Plate Tectonics Continued

• Lithosphere – rigid crust and uppermost layer that floats on top of asthenosphere (the plastic-like part)

• Floats on top and therefore can move.

Plate Boundaries

• Divergent – plates separate from each other• Convergent – Plates move towards each other

(smash together) One will subduct under the other. The denser plate goes under.

• Transform – slide past each other. Can get stuck and then slip causing Earthquake.

Draw this (doesn’t have to be perfect)

Draw the best you can

Draw the best you can

Notice the subduction (don’t draw)

Evidence

• Earthquakes – when a plate is stuck then slips• Volcanoes – magma erupting at plate

boundaries• Mountains forming where plates push

together.

Plate Motion

• So they move…. But how?• Convection – circulation of material caused by

differences in temperature.• Asthenosphere has convection currents.• The current moves the plates.

Plate Movement Continued

• Basal Drag – kind of like a conveyer belt moving the groceries at a store.

• Ridge Push – pushes the lithosphere (or plate) away from the other plate.

• Slab Pull – pulls a plate down towards the asthenosphere again.

Notice the types of movement

VIDEO!!!!!!!

• https://www.youtube.com/watch?v=0mWQs1_L3fA