The Theory of Plate Tectonics: Chapter Objectives

After completing this chapter, students should:

1. Appreciate that the theory of plate tectonics revolutionized the field of geology.
2. Know the continental drift theory and the evidence for it.
3. Understand Alfred Wegener's and Alexander Du Toit's pioneering contributions to continental drift theory.
4. Be able to explain why the idea of continental drift met with skepticism from most geologists.
5. Know what paleomagnetism is and how it provides evidence for continental drift.
6. Understand seafloor spreading and be able to summarize its main points and the facts that led Harry Hess to develop the idea.
7. Be able to explain how periodic reversals in Earth's magnetic field led to conclusive evidence for seafloor spreading.
8. Know the three main fault types and be able to explain the kinds of forces that produce them and the directions in which rock moves along them.
9. Understand what happens at mid-ocean ridges and how transform faults are created along them.
10. Understand what subduction is and be able to explain what happens at a subduction zone.
11. Know what the "ring of fire" is and why volcanoes and earthquakes tend to occur along its boundaries.
12. Be able to explain the three driving forces that keep lithospheric plates in motion.
13. Understand the difference between relative and absolute plate movements and be able to explain how each is determined.