B. Historical Development

1. Alfred Wegener - 1915 => continents have changed position on the Earth’s surface through time.

=> Continental Drift

- Pangea

300 m.y. old
Supercontinent

2. Wegener’s evidence:

a.  Jigsaw fit of the continent’s edges

b. Paleoclimate indicators at wrong latitudes

- glacial deposits (till & striations)
b. Paleoclimate indicators at wrong latitudes (cont.)

Coal

Reefs
 
Eolian Deposits

Evaporites

c. Fossil Evidence => fossil species match between  continents separated by oceans
d. Similar Geology on both sides of the Atlantic

 Rocks

 Structures

 Ancient Mountains
3. Problems with Wegener’s theory:=> an inadequate mechanism

 - floating continents
 
 - movement by centrifugal force (earth’s rotation)

 How to explain the oceans
- Wegner’s Pangaea did exist…….

 - continents didn’t drift apart
  moved apart by sea floor spreading