Transcript File
Aim: How does the Theory of Plate Tectonics influence the way the Earth is today? I. Plate Tectonics A. Theory of Plate Tectonics 1. The surface of the Earth is composed of about a dozen major rigid, moving crustal plates and several smaller plates 1.Plates a. Slabs of Earth’s lithosphere (crust and upper mantle) b. Average thickness is 100 km (62 miles) c. Most plates support both continent and ocean B. Continental Drift – states that the continents have drifted and still are drifting apart. C. Why do the plates move? 1. Due to tremendous heat, rock in the asthenosphere is like hot taffy 2.This allows plates to ride on top of hot, flowing rock. 3. Plates move because heat is being released from deep inside the earth. 4. Convection currents causes hot material to rise and expand (plates diverge) and cooler material to sink and contract (plates converge). Alfred Wegener D. Alfred Wegener – proposed that in the distant past, the Earth’s continents were all joined as a single landmass. 1. Evidence for his theory 1. South America and Africa would fit remarkably well, shoreline to shoreline. 2.If the Americas were moved next to Africa and Europe, there would be a match of ancient continental rocks and tectonic (fold and fault) structures. c. Pangaea – when Wegener placed all the continents together like a puzzle, it formed a large landmass which he called Pangaea. Fossil Evidence Plate Boundaries • http://geology.com/nsta/divergent-plateboundaries.shtml • http://www.iris.edu/hq/programs/education_and_ outreach/animations/11 • http://www.classzone.com/books/earth_science/t erc/content/visualizations/es0804/es0804page01. cfm?chapter_no=visualization Plate Puzzle Activity • Task: • With the bag of puzzle pieces place them together so that is forms a rectangular map. • Work together as a table group. On a separate sheet of paper answer the following question. Answer each question in COMPLETE SENTENCES. You may use Chapter 3 in the blue “Dynamic Earth” book as a reference. 1. What are the major features that correspond to the plate boundaries? 2. Compare the picture of earthquakes on page 61 with the map on page 65. How are they similar? What is a possible explanation for this? 3. What plate is North Carolina located on? 4. Who is Alfred Wegener? What did he discover? 5. Which plate is the largest? 6. What kinds of evidence are used to support the theory of continental drift? 7. Describe the three different types of plate collisions. 8. What is ocean-floor spreading? How does it relate to the theories of continental drift and plate tectonics? 9. How do you think living organisms have been affected by the movement of plates throughout Earth’s history? (hint page 73) 10. Create a Venn Diagram between the concepts: Plate Tectonics and Continental Drift