Plate Tectonics

An original Power Point presentation by Lindsey Durham

Plate Tectonics

• The crust of the Earth is not an unbroken shell but is made of plates (slabs of rock) that move.

Plate Tectonics

• Continental Drift– The plates are still moving today

• 4 inches/year

Plate Tectonics

• 3 Types of Plate Movements– Divergent– Convergent– Transform

Plate Tectonics

• Divergent plates– Occurs when 2

oceanic plates move apart.

– Magma from the mantle rises through the new crack.

– The magma cools and new ocean floor is created.

– This is called sea floor spreading.

Plate Tectonics

• Convergent Plates• 2 plates push against

each other.

– 3 types• 2 Continental plates• 1 Continental and 1 Oceanic• 2 Oceanic plates

Plate Tectonics

• 2 Continental– The 2 plates push

against each other making folds which create mountains.

Plate Tectonics

• 1 Continental and 1 Oceanic– Subduction occurs

• The oceanic plate slides under the continental plate because it is lighter.

• The impact causes crack in which magma flows up through.

• The cooled magma builds up creating volcanoes.

Plate Tectonics

• 2 Oceanic Plates– Subduction occurs and magma flows up the

crack forming volcanoes.

Plate Tectonics

• Transform Plates– 2 plates slide against each other– Fault lines created

• Cracks in the earth’s crust

– When the plates move the cause earthquakes

Plate Tectonics

• Tsunamis– Underwater earthquakes that can cause

HUGE waves.