1. SCIENCE JOLT
Nov 16 7. 1. 2. 2. 6.
Match the numbers to the correct letter: A. P-wave
B. S-wave
C. Inner Core
D. Outer Core
E. P-wave Shadow
F. S-wave Shadow
G. Epicenter 3. 3. 4. 5.

2. Plate Tectonics
The Continental Puzzle

5. Alfred Wegener
Not the first to notice that continents fit, but the first to seek and find supporting evidence for his hypothesis of “Continental Drift.”

6. Wegener hypothesized that the continents had once been a “super-continent” which he called “Pangea”
“Pangea” “All Land”

7. He also hypothesized that the continents began to break up 200 MYA, and then drifted to their present day locations.

8. Evidence 1. Matching Fossils
Lystrosaurus and Cynognathus were land reptiles.
Mesosaurus lived in fresh water lakes and shallow bays.
Glossopteris seeds, not likely to have blown or floated across the ocean.

9. Land Bridges?

10. Evidence 2. Rock Types Matching types of rocks:
Appalachians and Mountains in British Isles and Scandinavia – same age, same rock type.

11. Evidence 3. Ancient Climates
Glaciers leave scratches and grooves in bedrock when they move. Glaciers don’t move from sea onto land.
Evidence
3. Ancient Climates
Areas that are now tropical were once covered with glaciers.
At the same time, N America used to be tropical, as evidenced by vast coal deposits.

12. Theory of Continental Drift
Fossil Evidence
REJECTED
Geologic Evidence
Climate Evidence
No explanation for a push/pull force to cause motion of the continents.

13. Rejection of Wegener’s Hypothesis
Wegener died at age 50 while on an expedition in Greenland
At the time of his death, no one believed his hypothesis.

14. Scientists began using SONAR to exploring ocean floor.
Early 1900s
Scientists began using SONAR to exploring ocean floor.
SOund NAvigation Ranging
Sound waves bounce off ocean floor and return to ship. The longer they take to return, the deeper the water.

15. Deep Ocean Trenches and Mid-Ocean Ridges

16. Deep Ocean Trenches
Form deepest parts of the Ocean
Marianas Trench – Over 11 Km deep
Found mainly around the rim of the Pacific Ocean
Some in Indian Ocean and Atlantic Ocean

17. Mid-Ocean Ridges
First thought to be only in the center of the Atlantic Ocean
Over 70,000 Km long, and 1,000-4,000 Km wide
Longest feature on Earth’s Surface
Often have a long central valley,
called a Rift Valley
In Iceland, it rises above surface of ocean.