John Tuzo Wilson (October 24, 1908 – April 15, 1993) was a Canadian geophysicist and geologist who achieved worldwide acclaim for his contributions to the theory of plate tectonics. Plate tectonics is the scientific theory that the rigid outer layers of the Earth (crust and part of the upper mantle), the lithosphere, is broken up into around 13 pieces or "plates" that move independently over the weaker asthenosphere. Wilson maintained that the Hawaiian Islands were created as a tectonic plate (extending across much of the Pacific Ocean) shifted to the northwest over a fixed hotspot, spawning a long series of volcanoes. He also conceived of the transform fault, a major plate boundary where two plates move past each other horizontally (e.g., the San Andreas Fault). His name was given to two young Canadian submarine volcanoes called the Tuzo Wilson Seamounts. The Wilson cycle of seabed expansion and contraction (associated with the Supercontinent cycle) bears his name. Early life and education Wilson was born in Ottawa on October 24, 1908, the son of John Armistead Wilson CBE, and his wife, Henrietta Tuzo. Wilson's father was of Scottish descent and his mother was a third-generation Canadian of French descent. He became one of the first people in Canada to receive a degree in geophysics, graduating from Trinity College at the University of Toronto in 1930. He obtained a second (BA) degree from St. John's College, Cambridge in 1932 and then a doctorate (ScD). He then pursued further graduate studies as Princeton University, where he received a Ph.D. in geology in 1936 after completing a doctoral dissertation titled "The Geology of the Mill creek - Stillwater Area, Montana." Career In 1936, Wilson joined the Geological Survey of Canada as a government geologist. This was interrupted by the Second World War during which he served with the Royal Canadian Engineers, serving in Europe and reaching the rank of Colonel. He was involved in Operation Musk Ox. In 1946 he was appointed the first Professor of Geophysics at the University of Toronto. He made significant contributions to the theory of Plate tectonics, adding a concept of hot spots. Plate tectonics is the scientific theory that the rigid outer layers of the Earth (crust and part of the upper mantle), the lithosphere, is broken up into around 13 pieces or "plates" that move independently over the weaker asthenosphere. Wilson maintained that the Hawaiian Islands were created