SECTION 3 DRIFTING CONTINENTS

1. ALFRED WEGENER hypothesized that all of the continents had once been joined together in a SINGLE LANDMASS and have since DRIFTED apart.

2. Wegener named this supercontinent PANGAEA meaning “all LAND”.

3. Wegener’s idea that the continents slowly moved over Earth’s surface became known as CONTINENTAL DRIFT.

4. Wegener published all his evidence for continental drift in a book called THE ORIGIN OF CONTINENTS AND OCEANS.

5. Wegener used evidence from:

Landforms 1. When he pieced together maps, he noticed that a mountain range in SOUTH AFRICA lines up with a mountain range in ARGENTINA.

Landforms 2. EUROPEAN coal fields match up with similar coal fields in NORTH AMERICA.

Fossils 1. FOSSIL – any trace of an ancient organism that has been preserved in rock.

Fossils 2. Fossils of the REPTILES Mesosaurus and Lystrosaurus have been found in places now separated by OCEANS.

Fossils 3. Fossils of Glossopteris (a fernlike PLANT that lived 250 million years ago) have been found in rocks in AFRICA, South America, AUSTRALIA, India, and ANTARCTICA.

Climate 1. The island of SPITSBERGEN lies in the Arctic Ocean north of Norway. It has a harsh, POLAR climate. Fossils of TROPICAL plants are found on Spitsbergen. This made Wegener think the island was once located closer to the EQUATOR.

Climate 2. Deep scratches in rocks show that continental glaciers once covered SOUTH AFRICA. Today, the climate is too MILD for these thick layers of ice to form. Wegener concluded that South Africa was once much closer to the SOUTH POLE.

6. As a continent moves toward the EQUATOR, its climate becomes warmer. As a continent moves toward the POLES, its climate becomes colder. However, the continent carries with it the FOSSILS and ROCKS that formed at its previous location.

7. Wegener could not provide a satisfactory explanation for the force that PUSHES or PULLS the continents. Therefore, most geologists REJECTED his idea of continental drift.