Kenneth Deffeyes, professor emeritus of geosciences at Princeton, died Nov. 29, 2017, at the age of 85.

He graduated in 1953 from the Colorado School of Mines with a geological engineering degree. After two years of Army service, he earned a Ph.D. in geological engineering from Princeton in 1959. He then worked for Shell, evaluating oil fields.

Deffeyes taught briefly at Minnesota and Oregon State before joining the Princeton faculty in 1967, transferring to emeritus status in 1998. He helped reshape the curriculum at Princeton and elsewhere as the field began to incorporate plate tectonics into its understanding of the Earth’s formation.

John McPhee ’53 captured Deffeyes’ personality, passion, and deep knowledge of geological history and petrology in his book Basin and Range (1981), as he followed him cross-country to learn the story of the Earth’s development. Deffeyes was behind the geology field trips that enlivened beginning geology courses and freshman seminars, still taught today.

Deffeyes is survived by his wife, Nancy; two children (including Sarah Domingo ’91); and two grandchildren. The University flag was flown over East Pyne at half-staff in his memory.

Graduate memorials are prepared by the APGA.

Class Year: 
Graduate Class of 1959