Major Geological EventsCaused by

Plate Tectonics

Types of Boundaries• Divergent

― Plates move apart• Convergent

― Plates come together • Transform

― Plates slide horizontally past each other

Divergent Structures• New crust is formed as plates

pull apart• Land features include:

― Mid-Ocean Ridges Ex. - Mid-Atlantic Ridge

― Rift Valleys Ex. - African Rift Valley

― Earthquakes

Mid–Ocean Ridge (Location of Sea Floor Spreading)

Sea Floor Spreading (Mid-Ocean Ridge)

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Divergent Structure

Rift Valley

Divergent Structure

Convergent Boundaries• Crust is destroyed and recycled back into the

mantle• Three types of convergent collisions• Features include:

― Trenches – Mariana Trench― Volcanic Arc (Volcanic Mountains) – Andes

mountains― Mountain Ranges – Himalayan Mountains― Earthquakes

Subduction

• Result of convergent boundary• A more dense plate slides under a less dense

plate and sinks into the mantle.

• Features include:― Oceanic-Oceanic = Trenches― Oceanic-Continental = Mountain

Ranges

Subduction Examples

Convergent Boundary• Oceanic-Oceanic

• Land Features – Trench and Island Arc

Oceanic-Oceanic convergence

Convergent Boundary• Oceanic-Continental

• Land Features – Trench and Volcanic Arc (Volcanic Mountains)

Oceanic-Continental convergence

Convergent Boundary• Continental-Continental

• Land Features – Folded Mountains

Continental-Continental convergence

Mountain Ranges

Transform Fault Structures• Crust is neither destroyed nor created• Can occur between two oceanic plates

or oceanic-continental plates• Features include:

― Earthquakes― Fault line – San Andreas Fault

Transform Boundary• Oceanic-Oceanic

• Land Feature – Fault Line

Transform BoundarySan Andreas Fault Line

Transform Boundary• Continental-Continental

• Land Features – Fault Line

Earthquakes – All Boundaries

Volcanoes

Mountain Ranges

Putting It All Together

Plate Boundaries

Plate Movement