1. Alfred Wegener ( )

2. Established Hypothesis in 1912
All the continents were once joined together in a single landmass and have since drifted apart.
Wegener called this large landmass Pangaea

3. Evidence: (puzzle fit, fossils, rocks, climate)

4. Earthquake & Volcanic Evidence Paleomagnetism
Evidence for Continental Drift Theory Name ____________________Date__________
Rock Evidence (Landforms) Interactive Book pg 165 & ES pg470
Puzzle-Like Shape of Continents:
Observation that the continents seem to be able to “fit” together.
Fossil Evidence Interactive Book pg 166 & ES pg 470
Climate Evidence (Paleoclimatic) Interactive Book pg. 167 ES pg 471
Sea-Floor Spreading
Interactive Book pg 168 & ES 473
Earthquake &
Volcanic Evidence
Paleomagnetism
ES book p. 476

5. Puzzle-Like Shape of Continents:
Observation that the continents seem to be able to “fit” together.
Rock Evidence (Landforms)
Many rock layers in the U.S. (Appalachain Mts.) are identical to the rocks in parts of Greenland and Europe so at one time these rocks existed as one geologic structure.
Fossil Evidence
Climate Evidence (Paleoclimatic)
Glossopteris (fern-like plant) fossils found in present day Africa, S. America, Australia, India, & Antarctica.
Fossils of reptiles like Mesosaurus & Lystrasaurus found on different continents
Glossopteris fossils , a tropical plant, were found in present day Antarctica.
Coal deposits in present day Antarctica. Coal forms from decaying swamp plants
Glacial deposits in present day Africa, S. America, India, Australia
Sea-Floor Spreading
Earthquake &
Volcanic Evidence
Paleomagnetism
(ES book p. 476)
Sonar technology allowed mapping of the ocean floor and revealed the Mid-Atlantic Ridge. This ridge and others like it are created by sea-floor spreading.
HARRY HESS!
Iron-bearing rocks align with Earth’s magnetic field like a compass. This creates data to map the age of the ocean floor.
The magnetic pattern on one side of the mid-ocean ridge is identical to the pattern on the other side so the side formed together and spread apart.
Plotting of volcanic and earthquake activity reveals an outline of Earth’s tectonic plates, a key piece of evidence that Wegener was missing when presenting his theory.

7. Daily Assessment
Topic: Theory of Continental Drift Assignment: Can you name the 4 major pieces of evidence that Wegener used in support of his hypothesis regarding Continental Drift?

8. Harry Hess (Seafloor Spreading)
Seafloor spreading occurs at mid-ocean ridges (Mid -Atlantic Ridge). The seafloor is actually spreading apart. The discovery of the seafloor spreading strongly supports the theory of continental drift.
In the 1925’s, sonar was used in the discovery of the Mid –Atlantic Ridge

9. Mid-Atlantic Ridge

10. Mid-Atlantic Ridge