John Tuzo Wilson

1908-1993

Canadian Geologist

In 1963 John Tuzo Wilson revolutionized geology by suggesting that volcanic islands, such of those of Hawaii, had been formed by the movements of plates over a "hotspot" in the earth's mantle. This helped revive the theory of continental drift, which had suffered due to apparent contradictions—contradictions that Wilson's theory resolved. Two years later, in 1965, he offered another groundbreaking idea when he published a paper describing a third type of plate and plate movement, in addition to the two types already identified.

Born on October 24, 1908, in Ottawa, Ontario, Wilson was the son of a Scottish engineer who had immigrated to Canada. In 1930, when he earned his B.A. from Trinity College at the University of Toronto, he became the first student at any Canadian university to earn a degree in geophysical studies. Wilson went on to St. John's College, Cambridge, where he earned a second B.A. in 1932, then to Princeton to earn a Ph.D. in 1936.

From 1936 to 1939, Wilson worked with the Geological Survey of Canada. With the outbreak of World War II, he joined the Royal Canadian Engineers, a unit of Canada's army in which he attained the rank of colonel. Following the war's end, in 1946 Wilson became professor of geophysics at the University of Toronto. There he would remain until 1974, during which time he would perform the most significant work of his career.

By this time, the idea of continental drift, first put forward by Alfred Wegener (1880-1930) in the early 1900s, seemed to have come and gone. Geologists had returned to the belief that the continents were fixed in place, particularly in light of apparent contradictions, such as the fact that some volcanoes could be found many thousands of miles from the nearest plate boundary. Then, in 1963, Wilson published his revolutionary findings.

Perhaps the islands of Hawaii and those of other volcanic groups, Wilson suggested, had been formed not on the boundaries between two plates, but from the movement of a plate over an immovable "hotspot" in the mantle, deep beneath the plate. This resolved the contradictions in continental drift theory, and hundreds of studies since then have proven Wilson correct. However, at the time Wilson's ideas went so radically against the grain of received opinion that the major international scientific journals all rejected his manuscript. When in 1963 he finally did find a publication that would accept the paper, it was a relatively small one, the Canadian Journal of Physics.

Two years later, Wilson again presented a paper that contradicted prevailing opinion. Geologists knew of two types of plates and plate movement that connected trenches and ridges beneath the ocean: plates that moved apart, or divergent plates; and plates that moved toward one another, or convergent plates. Wilson now postulated a third type of plate boundary. Ridges and trenches, he observed, often end abruptly and "transform" into major faults that drop off sharply. These "transforms" or transform-fault boundaries, of which the San Andreas Fault in California is an example, offset the earth's crust horizontally, but do not create or destroy crust. As a result of Wilson's observations and those of others, continental drift theory was revived, helping to open the way for plate tectonics theory in the 1960s and 1970s.

Wilson's publications include One Chinese Moon (1959), IGY: Year of the New Moons (1961), A Revolution in Earth Science (1967), and Continents Adrift and Continents Aground (1977). He served as president of the Royal Society of Canada (1972-73) and the American Geophysical Union (1980-82), of which he was elected a fellow in 1962. His awards include the Walter H. Bucher Medal (1968) and the Mau Medal (1980). A range of mountains in Antarctica is also named for him.

Wilson remained at the University of Toronto until 1974, when he retired and became director general of the Ontario Science Centre. He served as chancellor of York University from 1983 to 1986, and died on April 15, 1993, in Toronto.

JUDSON KNIGHT