Earth's Structure

Core Structure

Convection Currents

Tectonic Plates

Plate Boundaries

Mantle - Nearer the earth's core, so is liquid, with a plastic and malleable texture. It is 3000km thick.

Outer Core - Made up of Nickel and Iron and is liquid, 2300km thick.

Crust - There are two types of crust: oceanic and continental. Continental is older and harder. It subducts beneath continental as it is denser. Upper mantle is included here as it is solid. It is 30 - 60km thick.

Inner Core - So much pressure is applied that it condenses and solidifies, mad up of nickel and iron. 1200km thick.

Step 2 - The rock is heated, causing the particles to move around and spread out, reducing the density, and causing it to rise towards the crust.

Step 3 - The tectonic plates provide frictional force and causes them to slide to the side. In some areas the oceanic tectonic plates subduct, causing the rock to sink back to the bottom, but in some weak spots, it melts the plates and rises towards the surface.

Step 4 - The sinking rock goes back towards the mantle and the cycle is repeated.

Step 1 - Heat radiates from the core with high temperatures and rises to the mantle.

Continental Plates

Oceanic Plates

Made of younger and denser plates. The friction from the convection currents causes them to drift around over millions of years. This causes a change in continental plates' relative position.

Made up of old rock, 1500km thick. They are of lower density. An example is the North American Plate

Collision Convergent

Destructive Convergent

Conservative Transformative

Constructive Divergent

Two plates meet, grinding past each other. Land is not created nor destroyed, but large amounts of pressure is built up, eventually being released in seismic waves, creating an earthquake. E.G San Fran Sisco, a city in which earthquakes are very prevalent.

Two continental plates meet. Due to their low densities, neither can subduct, so they both rise and fold to form mountains. E.G The Himalayas

Convection currents cause a gap in between tectonic plates, through which the magma rises, cools, solidifies and forms a volcano. E.G Mid Atlantic Ridge

Oceanic and Continental Plates meet, the oceanic plate subducts, forming a Trench. Pressure builds up in the Benioff zone, and when the oceanic plate melts as it nears the core, the pressure is released, causing an earthquake. E.G Nazca Plate subducting underneath the South American Plate.