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Chapter 7 Plate Tectonics: Open your IAN for today’s notes. Chap 7, Sec 3 Review Objectives: 1. Review subduction. (yes, again!) 2. What ocean features does it create? 3. What continental crust features are created by tectonic boundaries? 4. Brainpop Plate Tectonics • Sea-floor spreading and subduction can change ______________________ of the oceans. • The Pacific Ocean, aka__________ ______________, has lots of subduction zones, thus it is getting ______________. • The Atlantic Ocean is _____________. Sea-floor spreading is the process by which _________ ____________________ forms as magma rises toward the surface and solidifies. As the tectonic plates move away from each other, the sea floor spreads apart and magma fills in the gap. New Evidence to support Wegner’s claims? • Cooling & Shrinking of the Earth’s Crust • Sea Floor Spreading • Molten Material and Magnetic Stripes • Convection Currents Magnetic reversals in oceanic crust are shown as bands of light blue and dark blue oceanic crust. Light blue bands indicate normal polarity, and dark blue bands indicate reverse polarity What are Three Possible Driving Forces of Plate Tectonics? So what will happen as these plates in the ocean floor continue to spread? • Earth 100 Million Years from now • Convection Currents in the Earth. One more time, a different way! • Plate tectonics on a cocoa earth - YouTube 1. ______________ – when the ocean floor sinks beneath a deep ocean trench and gets swallowed by the mantle. 2. __________________– this feature forms from subduction (the oceanic crust bends downward forming a deep underwater canyon on the ocean floor). 3 Types of Boundaries have different effects. What are they? • 3 types of Boundaries in Review • With your hands, show me the 3 types of boundaries! Stand and Do! • Now let’s illustrate it! • HW: Flashcards!