1. The Earth’s Internal Processes: Continental Drift Theory
Sea Floor Spreading
Plate Tectonics
GMC Santos
San Beda College

5. Theory of Continental Drift by Alfred Wegener (1915)
The continents where once part of a super continent or single landmass (Pangaea) that broke apart 200 M years ago and had drifted horizontally to their current location

6. It was observed by cartographers that the edges of the continental shelves in the Atlantic Ocean have similar shapes

9. Evidences for Continental Drift: Puzzle
Edges of continental shelves almost fit together like pieces of a jig-saw puzzle

10. Evidences for Continental Drift: Fossil Records
Fossils of Mesosaurus have been found in South America and Africa

12. Evidences for Continental Drift: Climate Clues
Fossils of warm weather plants were found in Greenland
Glacial deposits and grooved bedrock found in southern areas of South America, Africa, India and Australia

13. Evidences for Continental Drift: Rock Records
Similar rock structures as found on different continents

14. Sea- floor Spreading
Ocean floor had “mountains and valleys” similar to continents above water
presence of ridges and valleys extending through the center of the Atlantic and other oceans of the world forming mountain ranges (mid-ocean ridges)