Comment: 25:55 - 26:53 (00:58)
Source: Annenberg/CPB Resources - Earth Revealed - 6. Plate Dynamics
Keywords: "James Sadd", "plate tectonics", modeling, theory, earthquake, volcano, mountain, orogeny, "sea floor spreading", mechanism, plate, "North American Continent", "Pacific Ocean", Rockies, "Alfred Wegener", "continental drift"
Our transcription: Plate tectonics is a model of the way the Earth works.
The significance of this theory lies in the fact that it connects many seemingly unrelated geologic phenomena, such as earthquakes, volcanic activity, mountain building, sea floor spreading.
Yet certain questions remain. For one thing, we don't fully understand the mechanisms that drive plate movement.
Also, it's undeniable that there are certain places where the geologic relationships don't fit easily into the plate tectonic model.
The western margin of North America between the Pacific and the Rockies is one such example.
However, unanswered questions like these don't mean failure.
Instead, they propel Science forward forcing scientists to reevaluate the assumptions of existing theories.
Nearly 100 years ago Alfred Wegener challenged the scientific orthodoxy with his theory of continental drift.
That challenge resulted in nothing less than a revolution in earth sciences.
Geology School Keywords