Continental Drift to... ...plate tectonics.
Succession of ideas:
- Continental Drift: key person is Alfred Wegener
- Sea-floor spreading: key person is A. Holmes
- oceans & continents are quite different
- compared to continents:
- ¥ oceanic crust is thinner ( 6 vs. 30-35 km)
- ¥ rock type is "basalt"
- ¥ oceanic crust is younger
- in addition:
- "active" mountains are at the edges of continents
- ocean has ridges in middle, trenches at edges
- earthquakes are at (some) continent-ocean boundaries
... Click for Sea-Floor Spreading a la Holmes.
- Plate Tectonics: many people, perhaps Vine & Matthews and J. Tuzo Wilson are ones to remember