Plate tectonics

Question 1

The earths structure

Answer 1

Crust
Lithosphere
Asthenosphere
Mantle
Inner core
Outer core

Question 2

Internal energy sources

Answer 2

Inner core - Very hot due to pressure and
radioactive decay (contains
elements like uranium that
give off heat when they
decompose)
This heat is responsible for
Earth’s internal energy, and
it spreads throughout

Question 3

Plate tectonic theory

Answer 3

The lithosphere is broken up into large slabs of rock called tectonic plates.
Plates move due to convection currents in asthenosphere –> push and pull the plates in different directions.
Convection currents caused when the less dense magma rises, cools, then sinks.
Edges of where plates meet are called plate boundaries (plate margins).

Question 4

Ridge push

Answer 4

Driving force for plate motion in plate tectonics that occurs at mid-ocean ridges as the result of the rigid lithosphere sliding down the hot, raised asthenosphere below mid-ocean ridges.

Question 5

Slab pull

Answer 5

When a plate subducts, the plate sinking into the mantle pulls the rest of the plate (slab) with
it, causing further subduction.

Question 6

Conservative plate margin

Answer 6

Plates are sliding past each other horizontally.
Crust is neither produced nor destroyed.
Plates made of rock with jagged edges –> catch and snag one another.
Friction and pressure between plates builds until the plates can’t take the stress.
Plates slip past each other, which can cause both plates to move resulting in the ground shaking.

Question 7

Constructive plate margin

Answer 7

Plates move apart.
Convection currents push apart plate and cause a gap.
Magma rises up to fill the gap.
New crust is generated as the plates pull away from each other.
Rift valleys are created when the crust pulls apart, and land drops to create a valley.

Question 8

Destructive plate margin

Answer 8

Happen when the oceanic plate slides beneath the continental plate.
Crust is destroyed as one plate dives under another at the subduction zone.
The rocks catch against each other as the plates are not smooth.
The pressure between plates builds until the plates can’t take the stress.
The plates slip past each other, which can cause both plates to move resulting in the ground shaking.

Question 9

What landforms occur at conservative boundaries?

Answer 9

Faults, earthquakes

Question 10

What landforms occur at destructive plate boundaries?

Answer 10

Ocean trench, fold mountains, stratovolcanoes, caldera volcanoes

Question 11

What landforms occur at constructive plate boundaries?

Answer 11

Volcanoes, ocean ridges, rift valleys