Chapter 2. Plate Tectonics and the Ocean Floor
1. relate in general terms how the availability of wartime technology and data contributed to the critical evidence for the acceptance of plate tectonics theory. What is the difference between continental drift and plate tectonics theory?
2. use a map to write a general description of the world ocean floor. What patterns do you see? (Your description should include terms such as mid-ocean ridge, faults, fracture zones, trenches, and island arcs.)
3. describe in general terms the process of sea-floor spreading.
4. evaluate the evidence for sea-floor spreading that comes from magnetic reversals, sea-floor sediments, and sea-floor topography.
5. calculate the velocity of sea-floor spreading.
6. summarize Darwin's theory of island coral reef formation.
7. understand how much data came together to support the idea of plate tectonics.
8. distinguish between the lithosphere and asthenosphere. Locate their boundaries.
9. illustrate the differences between the major types of plate boundaries: divergent (spreading center), convergent, and transform. Locate examples of each of these. What is the nearest example of each to you in La Plume, PA?
10. distinguish between the continental shelf, slope, and rise.
11. define subduction; give an example of a location where a subduction zone of each of the following types exists: ocean-ocean, ocean-continent, and continent-continent.
12. explain the movement of plates at a transform boundary; give an example of such a boundary in North America.
13. what is our best guess as to the force which powers the movement of the lithospheric plates.
Critical Thinking Questions and Activities:1. Which plate do you occupy? Speculate on the location of the world's next ocean; on a possible location of a developing great mountain chain.
2. Plot the distribution of quakes on a cross section through an ocean trench to see a Wadati-Beinioff zone appear.
3. Watch a 'lava lamp' in action. Compare its activity to that of the proposed mechanism of movement of plates by convection currents of magma within the earth.
4. Has the end of the cold war resulted in an increase of formerly classified military data that might speed our understanding of the ocean floor and plate tectonics?
5. locate the closest active hotspot to Keystone College. Do you think there is any relation between hotspot activity and 'hot springs' areas which have long been used as health spas? to areas of potential geothermal energy resources?