Plate Tectonic Theory

Plate Tectonic Theory

• Plate Tectonic Theory was proposed by Alfred Wegener in 1915.
• It describes the movement of the continents.
• Plate Tectonic Theory contributes to the theories of continental drift and sea-floor spreading.
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Plate Tectonic Theory

• The theory states that the lithosphere is split into plates which float on the mantle and core of the Earth.
• The core of the Earth is approximately 6000 degrees Celsius, this causes the molten rock in the mantle to heat up.
• This heating causes convection currents, which cause hot magma to rise and cool magma to sink in the mantle.
• The convection of the magma in these currents drags the plates in the crust in the same direction as the current through the processes of ridge push and slab pull.

Types of crust

• Oceanic CrustHeavy and dense
• Younger
• 5-10km thick
• Made of basalt
• Continental crust
• Lighter and less dense
• Older
• 20-200km thick
• Made of granite