1. Theories of Geological Evolution

2. First Stop Catastrophism How is it possible to explain the world around you, without science? Until the 1700s, most Europeans thought that a Biblical Flood played a major role in shaping the Earth's surface. Catastrophism – the theory that Earth’s features are mostly accounted for by violent, large- scale events that occurred in a relatively short amount of time.

3. Second Stop Uniformitarianism In the 1785 a new theory was proposed by James Hutton, called Uniformitarianism. Charles Lyell expanded on this theory and wrote “Principals of Geology.” Uniformitarianism – the theory that Earth’s features are mostly accounted for by gradual, small- scale processes that occurred over long periods of time.

5. Notes 1 st theory – Catastrophism Earth shaped by catastrophes 2 nd theory – Uniformitarianism Earth shaped gradually by constant geologic processes 3 rd theory – Continental Drift Continents were once connected and then drifted apart 4 th theory – Plate Tectonics Convection  seafloor spreading  push and pull of Earth’s plates

6. The Rise and Fall of a theory… and how it was saved changed. Using 4 lines of evidence, Wegener was able to identify that the continents were once assembled as Pangaea. Third Stop Continental Drift NAME the Evidence

8. Fourth Stop ---- Final Stop Plate Tectonics Solving the mystery of Drifting Continents. Harry Hess

10. With the person next to you: 1. Review your guided notes and list all of the evidences used in the theory of plate tectonics. 2. Draw a model of seafloor spreading and include the following aspects ◦Mid-ocean ridge (MOR) ◦2 lithospheric plates, include your crusts ◦2 Convection Currents