Wegener's theory: The role of geophysics in its eclipse and triumph

Abstract

Wegener's hypothesis of continental drift was based on a synthesis of world geological observations. Although there was much debate about the correctness of the geological interpretations, the chief objection to the theory came from the absence of a viable geophysical mechanism and in particular from the argument in favour of the mantle having finite strength. By about 1950 the hypothesis was widely rejected by geoscientists but soon after the development of palaeomagnetism provided what was needed to test it: a quantitative method of determining the position of the continents in the geological past. Comparisons of palaeomagnetic polar wandering curves from the different continents provided strong support for the essential ideas which Wegener had put forward. By the early 1960s the hypothesis of convection in the Earth's mantle made possible by solid state creep removed the basic geophysical objections to Wegener's theory. Sea floor spreading neatly complemented continental drift, and integrated into the concept of plate tectonics, has provided a framework in which much other geological and geophysical data fit.