87. Seafloor Spreading (1963)

Seafloor Spreading

Totally unexpected linear magnetic anomalies off the Canada/US west coast were first discovered in the 1950s. They remained inexplicable until it was recognized that Earth’s magnetic field periodically reversed in direction and that the source of the anomalies could be cooled lavas extruded at a series of linear ocean ridges. Such ridges had been recognized in many oceans, but their significance remained enigmatic.

Geological Survey of Canada geophysicist Lawrence Morley was one of the first to have the “eureka” moment that put all the pieces together when he suggested that the magnetic anomalies could be a kind of tape-recorder of the symmetric spreading of the ocean floor through time. 

In early 1963, Morley submitted his hypothesis about magnetic stripes and tectonic plate movement, first to Nature and then to the Journal of Geophysical Research. Both journals rejected his idea as too speculative. In June of that year he presented his idea to the Royal Society of Canada. Through an unfortunate coincidence, in September 1963, Nature published essentially the same hypothesis by British scientists Frederick Vine and Drummond Matthews. It was widely accepted, and they received credit for the idea. Subsequently, Morley’s contribution was recognized, and the concept is now known as the Vine-Matthews-Morley Hypothesis.

Category: Science Advances

Decade: 1960s


Cox, A., 1973. Plate Tectonics and Geomagnetic Reversals; W.H. Freeman and Company, San Francisco, 702 p.

Lear, J., 1967. 1967: Canada’s unappreciated role as a scientific innovator; Saturday Review, Sept. 2 1967, p. 45–50.

Vine, F.J. and Matthews, D.H., 1963. Magnetic anomalies over ocean ridges; Nature, v. 199, p. 947–949. doi:10.1038/199947a0

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