Derek York, geophysics professor, science writer (b at Normanton, Yorkshire, Eng 12 Aug 1936; d at Toronto, 9 Aug 2007). A leader in the field of potassium-argon dating of rock, Derek York was a foreign principal investigator for NASA during the Apollo missions to the moon. He came to the University of Toronto in 1960 from Oxford, where he had earned a doctorate of philosophy in earth sciences. His first book, The Earth's Age and Geochronology, written with Ronald M. Farquhar (1972), was translated into Chinese, and a subsequent book, Planet Earth (1976), into Japanese and Italian. In 1985 he won the past president's medal of the Geological Association of Canada for research in earth sciences and was elected a fellow of the Royal Society of Canada. He was chair of the physics department at the University of Toronto from 1992-1997, and was J. Tuzo Wilson Professor of Geophysics from 1995-2000.
He wrote science articles for the Globe and Mail from 1980-1992 and in 1986 won the Royal Society's Bancroft award for his contribution to public understanding of the earth sciences. In 1996 York was awarded the Sandford Fleming Medal of the Royal Canadian Institute. His last book, In Search of Lost Time, was published in 1997.