PLATE BOUNDARIES

Instructional Goals  Explain how each of the three plate boundaries are formed  Predict the resulting landforms from each boundary  Identify examples of plate boundaries

What do you know?  What do you know about earthquakes, mountains, etc?

Plate Boundaries  The place where two plates meet is called a plate boundary

Types of Plate Boundaries  Divergent  Convergent  Transform

Divergent Boundaries  Plates moving away from each other  When do divergent boundaries occur?

Examples of Divergent Boundaries  Mid-Atlantic Ridges  Iceland (rift area)  Red Sea  Lake Baikal  East African Rift

Convergent Boundaries  Plates are moving towards one another (colliding)  Destroys crust  What happens at a convergent boundary depends on the plates

Oceanic-Continental  - oceanic plate subducts because it is more dense  - examples:  Andes Mountains  Mount St. Helens (Juan de Fuca subducts beneath the North American plate)

Oceanic-Oceanic  - oldest crust subducts  - volcanic island chains  - examples:  Philippines  Japan  Aleutian Islands

Continental-Continental  - neither plate subducts  - forms mountains  - Examples  Himalayas  Appalachians  Rockies  Alps

Transform Boundary  - forms everywhere ridge is not a straight line  - two plates slide past each other  - crust is conserved

Examples  San Andreas Fault  Pacific Plate is moving faster than North American plate at a rate of about 2 cm per year

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How does it all connect?  Earth layers  Moving Plates  Continental Drift  Plate Boundaries  Divergent, convergent, transform fault  Earthquakes, volcanoes and mountains and things

Journal  “Tectonic” comes from the Greek word tektonikos, which means “of a builder”. Why is this word appropriate for tectonic plates? In what ways are tectonic plates responsible for building/destroying features of the Earth’s surface?