Plate Tectonics Chapter 4.5

Who is J. Tuzo Wilson and what was his idea? J.Tuzo Wilson proposed that all the lithosphere is broken into separate sections called plates. His idea lead to the current theory of Plate tectonics.

What is the theory of Plate Tectonics? The Theory of Plate Tectonics states that pieces of Earth’s lithosphere are in constant, slow motion, driven by convection currents in the mantle. The theory explains the formation, movement, and subduction of Earth’s Plates. Map with boundaries Plate tectonic video

Describe and draw the three types of plate boundaries. Three Kinds of Plate Boundaries: 1) Transform Boundaries Two plates slip past each other, moving in opposite directions. Earthquakes often happen at this kind of boundary. Transform boundary animation Plate tectonic video

2) Divergent Boundaries Two plates move apart. Most happen at the mid-ocean ridge. Rift valleys are a kind of divergent boundary that forms on land. Divergent plate boundary animation. Rift valley animation Plate tectonic video

Rift Valley

Convergent Boundaries Two plates come together. When two plates converge, or come together, a collision happens. Convergent Plate Boundary

Three types of convergent boundaries A.) Oceanic crust – Ocean crust What are the three types of convergent boundaries. What happens at each type. Three types of convergent boundaries A.) Oceanic crust – Ocean crust The plate more dense dives under the other plate. SUBDUCTION B) Oceanic Crust – Continental Crust The less dense continental crust can’t sink under the denser O.C., so the O.C. plunges beneath the C.C. SUBDUCTION C) Continental Crust – Continental Crust Subduction doesn’t happen. Instead the plates crash head-on and form mountain Ranges. MOUNTAINS c.c. colliding with c.c.video

Animation of all three plate boundaries. Animation of all three types. Plate tectonic video Bill Nye Plate tectonics Video Bill Nye.asf

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What causes the plates to move? Pacific Ocean is getting smaller and the Atlantic Ocean is getting wider due to seafloor spreading and subduction.