History of Continental Drift
- For the last 40 years, the theory of plate tectonics has provided geology's conceptual framework.
- An example of scientific revolution , this theory (and model) was assailed and ridiculed for 40 years before evidence accumulated in its favor.
- A descriptive predecessor of plate tectonics was continental drift.
- This hypothesis stated that at one time a super continent called Pangaea (Greek for "all land") existed.
- Pangaea broke apart and over time the continents drifted to their current positions.
Timeline of Continental Drift Theory Development:
- 1620: the British natural philosopher Francis Bacon mentioned the remarkable fit of the facing shores of the Atlantic.
- 1858: an Italian map maker, Antonio Snider-Pellegrini suggested that continents had at one time fit together.
- He based this claim on identical fossils found in European and North American coal deposits.
- 1915: Alfred Wegener, a German meteorologist, cited similarities in geometric fit, rocks, landforms and fossils as evidence that continents drift.
- Problems arose for Wegener:
- Wegener was not a geologist and so had less credibility with geologists.
- Geologists at the time were used to working with a "wrinkled apple" Earth model.
- A new scientific theory is difficult for scientists to accept.
- Wegener early attempts to describe how the continents moved were disproved.
- 1930: Doing research in central Greenland, Wegener died on the ice rescuing a colleague.
- 1960's : Sir Edward Bullard and associates used computers to get the best geometric fit. The results were better than had been expected; the best fits were found using the edge of the continental shelves.
- Late 1950's and 1960's : research in a variety of fields began to provide evidence.
- A more encompassing theory arose called plate tectonics.