BOWEN, NORMAN L.

born June 21, 1887, Kingston, Ont., Can. died Sept. 11, 1956, Washington, D.C. in full Norman Levi Bowen Canadian geologist who was one of the most important pioneers in the field of experimental petrology (i.e., the experimental study of the origin and chemical composition of rocks). He was widely recognized for his phase-equilibrium studies of silicate systems as they relate to the origin of igneous rocks. Bowen studied chemistry, mineralogy, and geology at Queen's University, Kingston, Ont., earning two degrees there by 1909. He obtained his Ph.D. at the Massachusetts Institute of Technology in 1912. That year he joined the Geophysical Laboratory of the Carnegie Institution of Washington, D.C., as an assistant petrologist. He was to spend much of his career there. By 1915 Bowen had executed a group of experimental studies that proved to be critically important to petrology and formed the basis of his critical review The Later Stages of the Evolution of the Igneous Rocks (1915), a paper of such outstanding merit that it established Bowen's position at the age of 28 as an international figure in petrology. Bowen resigned from the Geophysical Laboratory to return briefly to Queen's University as professor of mineralogy (1919), but after two years he returned again to the laboratory in Washington. There he remained for 16 years, broadening his attack on silicate systems. His researches carried great weight when he applied his experimental physicochemical data to field petrological problems. To this end he diligently visited classical localities relating to problems of igneous rocks: the Bushveld of South Africa, the alkalic lavas of East Africa, and the peridotites of Skye and the Fen area of Norway. In the spring of 1927, Bowen delivered a course of lectures to advanced students in geology at Princeton University, the substance of which was published in 1928 as The Evolution of the Igneous Rocks. In this vigorous presentation, Bowen provided a survey and a synthesis that have exerted a profound influence on petrologic thought. Later Bowen collaborated extensively with J.F. Schairer, a young and able experimenter who had joined the laboratory from Yale University. Together they worked on silicate systems containing iron oxide, beginning with ferric oxide and later ferrous oxide. Bowen made a second and more extended break from the Geophysical Laboratory when he taught at the University of Chicago from 1937 to 1947. He rapidly developed a school of experimental petrology there and produced a succession of papers by his pupils that dealt with equilibrium studies of alkali systems. Bowen himself presented a synthesis of these results in their bearing on the origin and differentiation of alkaline rocks (1945). After World War II, Bowen was induced to return once more to the Geophysical Laboratory in 1947 to cooperate in research on mineral systems embracing volatiles, particularly water. This work culminated in studies (published in 1958), with O.F. Tuttle as a collaborator, on the granite system. Bowen's association with the Geophysical Laboratory extended, in all, more than 35 years, and his long and splendid record was recognized by the award of honours from learned societies in the United States and Europe. He retired in 1952 but was still active and had an office in the Geophysical Laboratory as research associate until his death. Cecil Edgar Tilley The Editors of the Encyclopdia Britannica