1. Chapter 2: Plate Tectonics I LESSON 1 The Moving Plates

2. CRO #2 Describe Alfred Wegener’s original theory of continental drift. –What was Pangaea? When did it exist and what happened to it? Describe 4 pieces of evidence he used to support his theory. Explain why his theory was originally rejected by the scientific community.

4. Bill Nye clip from 100 greatest discoveries Alfred Wegener and continental driftAlfred alfred wegener song

5. The theory Continental Drift – a theory proposed by Alfred Wegener about 100 years ago that suggested that the continents were once connected and have since “drifted” apart. Pangaea – the name Wegener gave to the hypothetical supercontinent that existed when all of the major landmasses were once connected.

7. Pangaea It is believed to have existed between 245- 180 million years ago (late Paleozoic to middle Mesozoic eras). It slowly broke apart as the continents we know today drifted into their present day locations. As it broke apart, the Atlantic Ocean formed between landmasses once connected.

8. The Evidence This theory was an attempt to explain: –How matching fossils are found on widely separated landmasses. –The jig-saw fit of coastlines on opposite sides of the Atlantic ocean. –Matching rock formations and mountains on opposite sides of the Atlantic ocean. –Ancient climates very different from today’s in many places but not different on a global scale. (many landmasses must have been located at different latitudes in the past).

10. Glossopteris

13. Lystrosaurus

17. mesosaurus

18. Mesosaurus

21. Paleoclimates Paleoclimatic evidence that suggests landmasses were located at different latitudes in the past compared to today. Glacial ice sheets covering areas that are near the equator today (hot) while at the same time tropical swamps (coal beds) found in areas far from the equator today (cool climates).

23. Coal (200 million year-old deposits)

24. The problem (rejection) Alfred Wegener’s concept of continental drift did not catch on at first because: –He could not provide an explanation of how they could move; could not identify a force great enough to move them. –He believed the landmasses moved by sliding over the sea-floor; an idea quickly disproven based on the strength of the rock the continents are made of.