Abstract: Plate Tectonics

J. Tuzo Wilson

Science normally progresses by many small steps in a more or less logical progression. From time to time an important new concept demands a radical departure from past ideas. Examples of these scientific revolutions are associated with the names of Copernicus, Darwin, and Einstein.

To be successful, a scientific revolution must retain the methods and data which proved useful in the past, while, by some change in fundamental viewpoint, making possible advances impossible so long as the older ideas were held. Thus, no one could understand anything about the true nature of stars until it was realized that the sun and not the earth dominated the solar system.

It is difficult for anyone to persuade himself to accept a revolution because to do so requires more faith than logic. Acceptance is achieved only when the importance of the new developments are realized. Plate tectonics constitutes a scientific revolution and it is making possible great progress in the earth sciences.

The idea of continental mobility has developed through three stages: cataclysmic theories; the concept of drift of individual continents; and plate tectonics. The arguments for, and advantages of, the latter view are discussed, including mention of mobility of the earth's interior, palaeomagnetism, magnetic imprinting, geology of the ocean floors and of the continental margins.

The probability that a life cycle of ocean basins and mountain building should replace the concept of geosynclines is discussed and also past cycles of plate motion. Rifts of several different types seem to have formed at different stages in the cycle.

The probability that some plates are in motion relative to static parts of the deeper interior is indicated by hot spots and by palaeomagnetism. This seems to provide an explanation for the formation of island arcs, marginal seas, and the interior basins and swells which have formed during some stages of the development of continents, for example, during the Tertiary in Africa and during the early Paleozoic in North America.

AAPG Search and Discovery Article #90977©1975-1976 Distinguished Lectures