Plate Boundaries
Essential Questions: What is plate tectonics? What are the three types of plate boundaries? What crustal features are formed at plate boundaries?
Quick Action – INB Template Cut out the INB Template. Paste it into your notebook. The next two pages will go on top of this page to make a 3 page flip book. This Template is page 3. © KeslerScience.com
Quick Action – INB Template Page 2 Page 1 © KeslerScience.com
Plate Boundaries Seven Continents today © KeslerScience.com
Continental Drift Theory Theory of Plate Tectonics Plate Boundaries Continental Drift Theory Alfred Wegener developed the theory that the continents drift. At the time he did not know the mechanism that made this happen. Sea-Floor Spreading Harry Hess discovered that magma was rising on the sea floor causing it to spread. The hot magma rising in the mantle caused the spreading on the sea floor and the large pieces of crust (tectonic plates) to move. Theory of Plate Tectonics These two theories lead to the Theory of Plate Tectonics. © KeslerScience.com
Plate Boundaries Plate Tectonics is the theory that Earth's outer crust (lithosphere) is divided into several plates that glide over the plastic-like and less ridged asthenosphere (upper mantle). © KeslerScience.com
Plate Boundaries Convection Currents What is the engine that moves the plates? Convection Currents Transfers energy in the mantle Causes the hotter magma in the mantle to rise Causes the cooler magma in the mantle to sink © KeslerScience.com
Quick Action – INB Template Type of Boundary Sketch of Boundary Direction of Movement Description/Features of Plate Boundary Examples Divergent Plate Boundary Transform Plate Boundary Convergent Plate Boundary Collision Subduction Ocean-Ocean Ocean-Continent Complete the table as you move through the PowerPoint Presentation. Glue into your notebook as a reference. © KeslerScience.com
(neither destroys or creates crust) Plate Boundaries What happens at plate boundaries? Plates do one of 3 things. Converge (colliding or coming together) Diverge (dividing or moving apart) Transform (sliding past each other) Converge (destroys crust) Diverge (creates crust) Transform (neither destroys or creates crust) © KeslerScience.com
Quick Action – Plate Boundaries Ready for a song? The melody is to the “Adam’s Family.” Converging is colliding, Diverging is dividing, Transform is sliding, We are the plate boundaries. Dah na na na. <Snap, Snap> Bet you can’t get that out of your head! © KeslerScience.com
Plate Boundaries Divergent boundaries – dividing or moving apart Two oceanic crusts diverge and create a mid-ocean ridge (mountains under the ocean). This process is call sea-floor spreading. New crust is created. The Mid-Atlantic Ridge actually comes above the ground in Iceland. © KeslerScience.com
Plate Boundaries Divergent boundaries – dividing or moving apart Two continental crusts diverge and create a rift valley. New crust is created. Example is the Great Rift Valley in Africa Over millions of years water will eventually fill the valley. © KeslerScience.com
Plate Boundaries Transform boundaries Transform boundaries Plates slip sideways past each other creating earthquakes. Crust is neither created or destroyed. Many of these boundaries are found on the sea floor. The most famous transform boundary is the San Andreas fault in California. © KeslerScience.com
Plate Boundaries What happens when plates converge or collide? Continental/Continental = folded mountains (Himalayas). Continental/Oceanic = volcanoes form (Cascades in Oregon and Washington) Oceanic/Oceanic = Volcanic arc of islands form(Aleutian Islands in Alaska) © KeslerScience.com
Plate Boundaries Converging boundary -continental/continental boundary. Two continental crusts collide and push against each other. This pressure causes both plates to rise creating folded mountains. Not a subduction zone Himalaya Mountains © KeslerScience.com
Cascade Volcanoes in WA, OR and CA Plate Boundaries Converging boundary - continental/oceanic boundary The ocean crusts goes below the continental crust because its more dense. Volcanoes form on the continent. A trench forms at the place when the plates collide. Subduction zone Cascade Volcanoes in WA, OR and CA Old crust is destroyed © KeslerScience.com
Aleutian Islands in Alaska Plate Boundaries Converging boundary - oceanic/oceanic boundary Two oceanic crusts collide and push against each other. The older crust goes below the other one and creates a volcanic arc of islands. Subduction zone Old crust is destroyed Aleutian Islands in Alaska © KeslerScience.com
Quick Action – INB Template © KeslerScience.com
Quick Action – Plate Boundaries Let’s review the three types of plate boundaries. On three slips of paper write down C, D, or T. Get with a partner Decided which type of boundary you want to “act out.” Demonstrate to the class your “boundary” and have the class determine which type of boundary you are representing by holding up the corresponding letter, which represents converging, diverging and transform boundaries. © KeslerScience.com
Plate Boundaries Ring of Fire A long chain of volcanoes that surround the Pacific Ocean. One of the most geologically active area on Earth. Site of frequent earthquakes and volcanic eruptions. Caused by plate boundaries converging, diverging and transforming. © KeslerScience.com
Quick Action – INB Template Plate Boundaries Glue this side to Notebook after creating pocket with tabs Glue this side to Notebook after creating pocket with tabs Make pocket tabs in your notebook. Convergent Divergent Glue this side to Notebook after creating pocket with tabs Transform © KeslerScience.com
Quick Action – INB Template Cut out plate boundary cards and put them in the correct pocket in your notebook. © KeslerScience.com
Quick Action – INB Template Plate Boundaries © KeslerScience.com
Check for Understanding Can you… Explain plate tectonics? Name the three types of plate boundaries and describe their movement? Relate plate boundaries to the formation of crustal features: such as mountains, trenches, volcanoes and ridges? © KeslerScience.com