B3
Lesson Summary
Vocabulary Link
- plate tectonics
- plates
- divergent boundary
- rift valley
- constructive margins
- convergent boundary
- subduction zone
- destructive margins
- transform fault boundary
- conservative margin
- convection
- slab pull
- slab suction
- ridge push
- The theory of plate tectonics states that the upper surface of the Earth is broken up into a number of large chunks of rigid lithosphere plates that are constantly in motion.
- These lithosphere plates ride on top of the asthenosphere, a layer of plastic rock in the mantle that can flow.
- Divergent boundaries, also known as constructive margins, are areas where new crust is being created as two plates move away from each other.
- Convergent boundaries, also known as destructive margins, are areas where crust is destroyed as one plate is forced under another plate.
- Transform fault boundaries, also known as conservative margins, are areas where crust is neither created nor destroyed as two plates slide past parallel to one another.
- Convection is believed to be the underlying mechanism driving the motion of plates.
- Slab pull, caused by sinking plates in a subduction zone, is believed to be the dominant force acting on plates.