Plate Tectonics

Plate Tectonics

The Theory of Plate Tectonics states that the lithosphere of the Earth is floating on a semi-liquid layer called the asthenosphere. The lithosphere is divided into plates which continually change shape and move up to 5cm (2in.) per year.

The motion of the Earth's plates is driven by an unequal distribution of heat within the Earth. Hot material in the mantle moves upwards toward the surface of the Earth while cooler material in the mantle sinks back to the core of the Earth creating a convection current system.

There are 7 Major Plates

• North American
• South American
• Pacific (largest)
• Australian-Indian
• African
• Eurasian
• Antarctic

Intermediate Plates Include:

• Caribbean
• Nazca
• Philippine
• Arabian
• Cocos
• Scotia

There are over 12 smaller plates known to exist.