Plate tectonic theories

Question 1

Slab pull

Answer 1

The denser plate sinks back into the mantle under the influence of gravity. It pulls the rest of the plate along behind it.

Question 2

Ridge push

Answer 2

magma rises through fissures as the plates move apart. The magma cools to form new plate material. As it cools It becomes denser and slides down away from the ridge. This causes other plates to move away from each other.

Question 3

Seafloor spreading

Answer 3

The process by which new oceanic crust is formed at mid oceanic ridges and outwards, pushing older crust away from the ridge

Question 4

Convection

Answer 4

radioactive decay heats the lower mantle, causing the magma to become less dense and rise. Once it reaches the upper mantle it cools, becomes more dense and sinks. This process repeats forming convection currents