Earth and Planetary Science
EPS Geophysics

John Verhoogen

John Verhoogen (1912 - 1993)

Born in Brussels in 1912, John Verhoogen was a leading contributor to the modern understanding of Earth's dynamics. Even though he contracted poliomyelitis when he was 17 years old, he obtained degrees in mining engineering (at the University of Burssels, 1993) and engineering geology (at the University of Liege, 1934). He earned his Ph.D. in geology (1936) at Stanford University, although he studied mainly at UC Berkeley with Howel Williams. Later, after another period at the University of Brussels (1936-1939), he undertook research in the Belgian Congo making geophysical observations of the active volcano Nyamuragira. He remained in the Congo during the Second World War working on the procurement of strategic minerals. In 1947 he joined the faculty of the Department of Geological Sciences (now Geography and Geophysics) at UC Berkeley. He flourished there for the next thirty years until his retirement in 1976. He was a fellow of the Royal Astronomical Society (elected 1950), the American Geophysical Union, the Geological Society of America, and the American Academy of Arts and Sciences, and a member of the National Academy of Sciences and numerous other professional organizations. In 1978 he received the Arthur L. Day Prize and Lectureship from the National Academy of Sciences for his fundamental work on the thermodynamics of the Earth's core and mantle and contributions to scholarship in the Earth sciences. Other awards included two Guggenheim Fellowships, the Day Medal of the Geological Society of America (in 1958), and the Dumont Medal of the Geological Society of Belgium. Verhoogen served actively on a number of national and international advisory panels and editorial boards. From 1951 to 1954 he was vice-president of the International Association of Volcanology and Chemistry of the Earth's Interior.

John Verhoogen was an inspiring teacher of geophysics, an open, yet critical, witness of both classical and modern methods as well as the latest discoveries in the Earth sciences. The lucidity with which he spoke and wrote and his nearly total recall of detail were extraordinary. Moreover, he had an uncanny ability to penetrate quickly to the heart of a scientific problem and lay it bare with a few bold strokes. Emerging from a Verhoogen lecture, one would commonly hear both graduate and undergraduate students alike praise the professor's breathtakingly clear account of how the Earth works. His belief that analytic methods should be used in teaching geology is exemplified in the undergraduate textbook The Earth (Holt, Rinehart and Winston, New York; 1970), of which he was the principal author. The text's approach was before its time for most geology departments.

Verhoogen was a highly influential and successful mentor to some of the outstanding geologists and geophysicists of the last half century. Among these were his students Alan Cox and Richard Doell, who subsequently made critical contributions to the theory of plate tectonics. He courageously defied the general antipathy to the theory of continental drift common in the 1950s in geology departments at American universities. Verhoogen later stated that he was an advocate of drift at an early stage just because Paul Fourmarier, his professor at Liege, was opposed to it. "I became fervently disposed to it, just on the general principle that you don't believe what your professors tell you," he said. He was influenced early on by notions of large-scale convection in the Earth's mantle and, unlike Sir Harold Jeffreys of Cambridge, who was the most influential opponent to drift, in 1948 he saw no physical objections to it and felt that lack of a mechanism did not preclude it. Notwithstanding, he wrote of Jeffreys' The Earth, "Most of it I did not understand (in 1934), but it nevertheless made a profound impression on me."

During the 1950s Verhoogen played a central role in developing geochronology and paleomagnetism studies at Berkeley. When physics professor J. Reynolds designed the mass spectrometer--which became a vital part of the development of the potassium-argon method of dating minerals--Verhoogen provided him rock samples possessing the greatest variation in isotope ratios. About the same time Verhoogen and his graduate students launched an investigation of the paleomagnetism of rocks and minerals at Berkeley, with particular attention to questions of geomagnetic polarity reversals and continental drift. Potassium-argon dating of paleomagnetic rock samples of both polarities collected around the globe, undertaken mainly by Berkeley-trained scientists in labs at Berkeley and elsewhere, demonstrated the existence of a global polarity time scale and thereby proved that the geomagnetic field had indeed reversed itself many times in the past. The polarity time scale also turned out to be central to the sea-floor spreading model and plate tectonics. The history of these developments and the pivotal parts they played in the plate tectonic revolution are described in detail in The Road to Jaramillo (William Glen, Stanford, 1982), which quotes from letters to Verhoogen and interviews with him and his students on this subject. Initially, Verhoogen's adherence to deep Earth convection was limited: "My concerns about convection were directed toward resolution of questions about the generation of magma and transfer of heat to the surface and temperature distribution in the mantle, but not directed toward resolution of the drift question." Nevertheless the dynamic Earth theory was key to attracting students with the background in physics that allowed them to construct the geomagnetic reversal time scale and to have the freedom to accept the model of interaction of more-or-less stable lithospheric plates. Verhoogen also contributed significantly to the modern development of geology through collaboration with his Berkeley colleague F.J. Turner. In 1951 they published Igneous and Metaphoric Petrology (McGraw-Hill, New York). This and subsequent revised editions (in final form titled Igneous Petrology, with I.S.E. Carmichael and F.J. Turner, 1974) became the most widely used and influential textbook on the subject. Turner was strong in field geology and laboratory petrology but was no mathematician.

As post-polio syndrome increasingly restricted his physical capability, Verhoogen made the brilliant decision to shift his focus to theory. Verhoogen's singular contribution was his comprehensive thermodynamic treatment of rock genesis. With this emphasis, he sought to provide the necessary rigorous and quantitative underpinning for crystallization from melts or recrystallization of pre-existing rocks at high temperatures. It now seems amusing that a referee unsuccessfully suggested that Verhoogen's innovative chapter on chemical thermodynamics be deleted on the ground that it would be "incomprehensible to geologists and useless to petrologists." Indeed, this treatise illustrates clearly Verhoogen's foresight as well as his theoretical insights and mathematical ability, and his willingness to grapple with fundamental geological problems through thermal engines, convective motions, melting, and volcanism. In his published research Verhoogen contributed to our understanding of properties of volcanoes and temperature distribution in the Earth. His views on thermal expansion of solids and terrestrial heat balances were widely quoted. These interests led to a characteristically iconoclastic monograph entitled Energetics of the Earth, published by the National Academy of Sciences (1980), which combined four lectures he delivered as a recipient of the Arthur L. Day Lectureship. Verhoogen later explained that the topic of the lectures had been of great interest to him "for more than forty years, but remains largely speculative." In 1983 he summarized his position on geophysics: "On the theoretical side perhaps the greatest step forward since the discovery of radioactivity has been the recognition of convection as the dominant mode of heat transfer in most of the mantle and core. Here at long last is something to hang onto."

It is not an exaggeration to call Verhoogen one of the first truly quantitative Earth scientists. He was given to devastating but often witty criticisms of geological positions with which he did not agree. He was, however, always generous in collaboration with colleagues and students and his presence will be remembered particularly for his fairness and lively conversation. Verhoogen was married to the late Ilse Goldenschmidt, a native of Austria. He is survived by two sisters, both of Brussels, four children, Robert H. of San Francisco, Alex R. of Spokane, Washington, Therese of Berkeley, and Sylvie Biramonte of Borex, Switzerland; and seven grandchildren.

To preserve his memory, interested individuals may direct contributions to graduate student fellowships in the UC Berkeley Earth & Planetary Science Department. Checks should be made out to "The Regents of the University of California" and addressed to Front Office, Department of Earth and Planetary Science, 307 McCone Hall, University of California, Berkeley, CA, 94720-4767.

In Memoriam written by Bruce A. Bolt, Robert Coe, Richard R. Doell, and Charles Kittel.