Intro Objective 10/5/11 Describe the three types of tectonic plate boundaries. What do you think forms when two tectonic plates collide? What about when they divide?

Plate Boundaries

3 Types of Boundaries Divergent boundary –Plates separate –2 types Transform boundary –Plates slide past each other –1 type Convergent boundary –Plates collide –3 types

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Plate Boundaries Continental- Continental divergence Rift valley Small volcanoes and earthquakes Example: African Rift Valley Deep valley that forms when 2 continental crusts move apart

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Divergent Boundary

Oceanic-Oceanic divergence Mid-ocean ridge Small volcanoes and earthquakes Example: Mid-Atlantic Ridge Underwater mountain chain’s and valley’s created by sea-floor spreading

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Plate Boundaries Transform Boundary Plates slide past each other Many earthquakes occur here Example: San Andreas Fault in CA

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Convergent Boundary Oceanic-Oceanic collision Subduction Deep-ocean trench Creates huge volcanoes and earthquakes Example: Philippine islands Process of denser crust sinking down into mantle Valley/canyon created at subduction zone

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Oceanic – Oceanic Collisions

Continental-Oceanic Collision Subduction of ocean plate Powerful volcanoes and earthquakes Forms mountains Example: Andes mountains in Chile

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Continental – Oceanic Collisions

Continental- Continental collision Creates HUGE mountains Both crusts move upward since neither are dense enough to sink into mantle Example: Himalayan Mtns. in India

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Continental – Continental collisions

(Tectonic Plates Video - F4)

Plate Boundaries Summary: Plates can collide into each other, separate and slide past each other creating the three types of plate boundaries: Divergent, Convergent and Transform. These boundaries create many different types of landforms on Earth.

Outro Objective 10/3/11 Explain that the earth's lithosphere is composed of many plates rather than one continuous piece What do you think makes these plates move into each other?