1946-1974
Calm Before
the Storm

Evolution of A Theory

Related Stories:

 The Theory

 The Debate

 The Lecture

 The Evolution

It could be argued that global plate tectonics theory evolved from such a range of scientific inquiry and observation that the complete list of contributors would have to include Leonardo da Vinci, who in the 15th century observed that:

"Above the plains of Italy where flocks of birds are flying today fishes were once moving in large shoals."

No such honor roll can be attempted here. What follows is an incomplete list, even for the short period of history it addresses.

But the years immediately following World War II were so filled with research breakthroughs that a partial listing at least provides a sense of the chronological sequence of events leading up to one of history's most profound advancements in geological science.

 1944

Arthur Holmes authored the classic textbook, Principles of Physical Geology. Following an idea dating back to the 1830s, revitalized in the 1930s by himself, F.A. Vening Meinesz and David Griggs, Holmes reintroduced thermal convection in the mantle as a possible mechanism for continental drift.

 1946

Harry H. Hess published his discovery of guyots, flat-topped submarine volcanoes in the Pacific, which provided early evidence for seafloor spreading.

 1952

H.W. Menard and Robert S. Dietz discovered fracture zones in the Pacific Basin that were recognized as being associated with lateral faulting. These zones later became significant as a means of determining the direction of plate movement.

 1956

Maurice Ewing and Bruce Heezen, Lamont Geological Observatory, reported that narrow troughs or rift valleys run along the crests for most of the length of the extensive submarine mountain chains in the Antarctic, Indian and Atlantic oceans.

J. Hospers, S.K. Runcorn, K. Creer and E. Irving, graduate students at Cambridge University in the early 1950s, began applying an intensively statistical method of paleomagnetism to the problems of polar wandering associated with continental drift. By 1956 Runcorn and Irving had refuted the Darwinian belief that the earth was too rigid for polar wandering or continental drift by using paleomagnetic data to demonstrate that both had occurred.

 1959

Allan Cox began paleomagnetic research that confirmed the earlier work (1920s) of Motonari Matuyama, which concluded that the earth's magnetic field had reversed during the early Pleistocene.

 1962

Hess's historic article, "History of the Ocean Basins," was published, suggesting that the continents do not plow through oceanic crust, but are carried on mantle that is overturning due to thermal convection.

 1963

Fred Vine and Drummond Matthews of Cambridge explained the linear magnetic anomalies parallel to active ridges by correlating earlier theory on seafloor spreading with research then being done on the time scale for geomagnetic reversals.

 1964

J. Tuzo Wilson, University of Toronto, postulated that oceanic islands such as the Hawaiian Islands were formed by the movement of a plate over a hot spot deep in the mantle. In 1965 he recognized a new class of faults and wrote the definitive paper on transform faults and their bearing on continental drift.

 1965

Bullard, Everett and Smith of Cambridge introduced axis of rotation to describe displacement on a sphere, a geometric technique that became an important tool for later plate tectonic studies.

 1967

Dan McKenzie, Scripps Institute of Oceanography, created a geometric model that employed rigid-body rotations to explain the mechanics of plate tectonics on a sphere.

James Heirtzler, Lamont-Doherty Geological Observatory, was the first to make use of the recent technological development of a self-operated, medium-sized computer to organize the massive amount of magnetic data collected on the observatory's oceanographic cruises, enabling researchers to plot profiles at any scale and compare data from different areas.

Robert Parker, Scripps, completed a computer program called Supermap for plotting worldwide geophysical data using any projection. He hit upon the idea of using a Mercator projection to plot plate tectonics, which proved highly useful in later studies.

Walter Elsasser, at Princeton, devised a theory that showed how a rigid ocean plate resting on a soft layer could transmit stress over great distances.

W. Jason Morgan, also at Princeton, developed a method for finding pole locations from variations in the rate of seafloor spreading, as determined from magnetic stripes. He also produced the first map showing the major plates of the world.

 1968

Xavier Le Pichon, Lamont Geological Observatory, adapted the computer methods of McKenzie, Parker and Morgan to handle much more vast quantities of geophysical data and produced a geophysical analysis of all the major plates of the world. Combining information from magnetic stripes with geologic data, he also retraced the past history of plate motions.

 1970

Arthur Maxwell, Richard Von Herzen, K.J. Hsu, James Andrews, Tsunemasa Saito, Stephen F. Percival Jr., E.D. Milow and Robert Boyce reported on the 18-month South Atlantic ocean cruise of the Glomar Challenger for the Joint Oceanographic Institutions for Deep Earth Sampling. Their findings provided conclusive evidence confirming the global hypotheses of seafloor spreading and continental drift and signaled the arrival of a new era in geologic research -- global plate tectonics.

Information for this article was drawn almost entirely from a text compiled by Allan Cox, Plate Tectonics and Geomagnetic Reversals, 1973, W. H. Freeman and Co.