He also introduced Bowen to some of the possible causes of differentiation, such as dif- fusion, fractional crystallization, crystal seg- regation, gaseous transfer, immiscibility (liquation), and assimilation. Probably Charles H. Warren imbued Bowen with the Norman L. Bowen: The principles of physical chemistry as applied to mineralogical and petrological problems. Experimental Approach It was clear that he had already focused on igneous differentiation and the principles to Petrology of physical chemistry.
H. S. Yoder, Jr., Geophysical Laboratory, Carnegie Institution The Experimental Experience of Washington, Washington, DC 20015, [email protected] In 1910, at the suggestion of T. A. Jag- gar, then at MIT, Bowen applied to the Geo- physical Laboratory at the Carnegie Institu- tion of Washington to do an experimental he greatest petrologist of the 20th crops was done under a blanket of mosquitoes study related to a geological field problem century is clearly Norman Levi and black flies. Bowen could use an axe and for partial fulfillment of the requirements of Bowen (1887–1956). He promoted tump line, make pace-and-compass surveys, the Ph.D. As the laboratory’s first predoc- the solution of petrological field and cook. In the course of his mapping, he toral Fellow, he was assigned the “nephelite Tproblems by the application of principles became interested in the differentiation of problem,” a favorite topic of J. P. Iddings. At deduced from simple phase diagrams of the diabase. that time, most of the experimental tech- end members of common rock-forming niques for high temperatures used today minerals, thereby providing a quantitative Courses Chosen were all in their early stages of develop- approach to a field previously concerned As a result of his field experiences, ment. The controllers for the high-tempera- only with observation and classification. when he returned to Queen’s University, ture furnaces were very large street-car-type Despite his quiet personality, subdued pre- Bowen registered in the School of Mining, banks of resistor coils; platinum-rhodium sentations, droll sense of humor, and even taking mineralogy and geology. After two thermocouples had just been calibrated to his small stature, he was a giant. more field seasons around Lake Abitibi and 1755 °C by Day and Sosman (1911); the Gowganda Lake, again paying attention to quenching method had just been invented Work and Play the diabases, he won a prize of $25 and the by Shepherd, Rankin, and Wright (1909). As a youth, Bowen helped his father in President’s gold medal from the Canadian Wright (1910) had perfected a new petro- the family bakery, driving the delivery rig— Mining Institute for the best paper submit- graphic microscope for examining fine- an experience that resulted in his enduring ted by a student: “Diabase and aplite of the grained synthetic preparations. Particularly distrust of horses. Winters were spent ice cobalt-silver area.” (See 1956 edition of important was the development of a calcu- skating, and during the summer months he Bowen [1928] for references to his pub- lation scheme for translating the chemical became a strong breast-stroke swimmer and lished works.) Trained in the Canadian analyses of rocks, whether crystalline or took part in races. He sang in the choir of bush on the myriad of variables in natural glassy, into a set of end-member minerals, the local Anglican church and is alleged to geological processes, he had rapidly the CIPW normative system (Cross et al., have had a fine tenor voice. absorbed the principles of geology and 1902), that could be simplified for labora- chemistry. On graduation in tory experimentation. In addition, the the- The Field Experience 1909, he won a London Exhi- ory of solid solutions had been laid out by Public schools in bition of 1851 Scholarship, H. W. Bakhuis Roozeboom (1901). In short, Kingston, Ontario, had pre- which gave him the opportu- Bowen arrived at a most opportune time pared him for college entrance nity to continue on in gradu- to do the nepheline-anorthite system—all examinations at Queen’s Uni- ate school. the tools and theory were in hand. The versity. Even though registered nepheline-anorthite diagram was deter- in the arts course with the Charismatic Teachers mined with considerable efficiency with 17 intent of becoming a teacher, He was first attracted to different mixtures and 55 quenching experi- Bowen had the urge, as many Norway because of J. H. L. ments under the tutelage of E. S. Shepherd young people do, to see new Vogt’s (1903–1904) book, Die and F. E. Wright. That simple system, the and alluring country and to Silikatschmelzlösungen and by first example found in silicates of solid solu- earn some money. He joined W. C. Brøgger, who had an Ontario Bureau of Mines applied physicochemical prin- geological mapping party to ciples developed in the inves- Larder Lake under the leader- tigation of slags to the prob- ship of R. W. Brock. Brock, lem of differentiation. Bowen who was an outstanding per- was discouraged, however, The sonality and eventually from going to Norway because courtship became Director of the Geo- of the language barrier and of N. L. logical Survey of Canada, because Brøgger was too busy Bowen had so much confidence in with legislative duties. Instead, and Mary Bowen’s inherent abilities, in Bowen went to MIT to study Lamont, a medical addition to his skills for sur- under the sparkling and student in viving in the bush, that he left charismatic teacher Reginald Boston. the young man to carry out A. Daly, who indoctrinated the work alone! Travel in the Norman L. Bowen on his him with the idea that basaltic bush was by canoe, and first job involving land liquid was a primary magma traversing in search of out- surveying. and all others were derivative.
10 GSA TODAY, May 1998 method, even though they recognized the above sequence until a satisfactory solution system as one of the Roozeboom theoreti- is achieved, recognizing that any new cally possible types, with continuous solid observation or inconsistency may initiate solution containing neither a maximum the process again. nor minimum. With the quenching method and run times of only 1/2–2 hours, Successful Philosophy Bowen was able to generate the entire pla- After half a century, it is clear that his gioclase diagram, well documented with philosophy had been successful even later studies. It provided the basis for his though new interpretations of the details subsequent views on magma differentiation were required (Yoder, 1979). Bowen’s and crystal fractionation, both old ideas legacy, in addition to the many accurate (Scrope, 1825; Becker, 1897) but lacking and precise phase diagrams of the end experimental demonstration. members of common rock-forming miner- als, is the construction of an experimental A New Integrated Approach and theoretical basis for the interpretation Several alternatives for the processes and documentation of the diversity of leading to magma diversity had already igneous and metamorphic rocks. been presented and explicitly summarized by Iddings (1892). But Bowen set out his References Cited prejudices forcefully and clearly in 1915 in Becker, G. F., 1897, Fractional crystallization of rocks: American Journal of Science, ser. 4, p. 257–261. two papers after studying only two more, The plagioclase phase diagram, with temperature Bowen, N. L., 1928, The evolution of the igneous rocks: in °C and the seven new synthetic and two natural yet most critical, phase diagrams illustrat- Princeton, New Jersey, Princeton University Press, anorthite-albite compositions studied, indicating ing the reaction principle. One paper, “The 334 p.; second edition, 1956, New York, Dover. the liquidus (upper curve) and solidus. The melt- later stages of the evolution of igneous Cross, C. W., Iddings, J. P., Pirsson, L. V., and Washing- ing point of anorthite was already well established rocks,” provided a flexible, broad theory ton, H. S., 1902, A quantitative chemico-mineralogical and used as a point for thermocouple calibration. classification and nomenclature of igneous rocks: Jour- based on quantitative experimental obser- nal of Geology, v. 10, p. 555–690. vations that he defended with rigorous Day, A. L., and Sosman, R. B., 1911, High temperature argumentation. As a result of his incredible gas thermometry: Carnegie Institution of Washington perceptiveness and intuition, Bowen had Publication 157, 129 p. tion combined with polymorphism, gener- integrated all the new experimental meth- Day, A. L., Allen, E. T., and Iddings, J. P,. 1905, The iso- ated in Bowen’s mind a much larger picture. morphism and thermal properties of the feldspars: ods, physicochemical theory, and field While writing his thesis he also managed to Carnegie Institution of Washington Publication 31, 95 p. observations into a unified new approach produce in 1912 a paper of lasting value, Iddings, J. P., 1892, The origin of igneous rocks: Philo- to petrology. It was his clarity of presenta- sophical Society of Washington Bulletin, v. 12, “The order of crystallization in igneous p. 89–213. tion, documentation of principles with rocks.” With this publication at age 25, experimental demonstrations, and applica- Roozeboom, H. W. Bakhuis, 1901, Die Heterogenen Bowen had introduced the precursor to a Gleichgewichte vom Standpunkte der Phasenlehre: tion to specific field problems that eventu- Braunschweig, Germany, Friedrich Vieweg und Sohn, major change in the approach to petrology. ally made his 1928 book The Evolution of the Vol. I—221 p.; Vol. II, 3 parts—467 p. (1904); 226 p. (1918); 199 p. (1918); Vol. III, 2 parts—313 p. (1911); Igneous Rocks, the handbook for petrologists Career Decision 348 p. (1913). worldwide. It was with some reluctance In the summer of 1911 Bowen was in Scrope, G. P., 1825, Consideration on volcanoes: Lon- that field geologists eventually accepted don, W. Phillips, 270 p. the field again with Reginald Daly, surveying Bowen’s philosophy as leading to the most Shepherd, E. S., Rankin, G. A., and Wright, F. F., 1909, the Shuswap terrane of British Columbia, satisfactory interpretation of the facts as The binary system of alumina with silica, lime and famous for its crosscutting granites and magnesia: American Journal of Science, ser. 4, v. 28, they were perceived by geologists: (1) recog- wholesale injection. In spite of his absences p. 293–333. nition of a set of field observations that from Boston, he managed to court Mary Vogt, J. H. L., 1903–1904, Die Silikatschmelzlösungen appear to be related; (2) simplification of mit besonderer Rucksicht auf die mineralbildung und Lamont, and they were married on October these relations into a set of laboratory die Schmelzpunkt-Erniedrigung: Christiana, Norway, 3, 1911. Upon graduation from MIT on June Jacob Dybwad, 235 p. experiments analogous to the conditions 4, 1912, he had offers from Jaggar, then at Wright, F. E., 1910, A new petrographic microscope: believed to have existed in nature; (3) exe- the Volcano Observatory in Hawaii, for a American Journal of Science, ser. 4, v. 29, p. 407–414. cution of those experiments in an unam- post in economic geology at Tucson, for a Yoder, H. S., Jr., 1979, The evolution of the igneous biguous manner; (4) application of the rocks: Fiftieth anniversary perspectives: Princeton, New position at the Geological Survey of Canada, principles derived from the experimental Jersey, Princeton University Press, 588 p. and for the job of assistant petrologist at the results to specific field occurrences; (5) re- Yoder, H. S., Jr., 1992, Norman L. Bowen (1887–1956), Geophysical Laboratory. After another field MIT class of 1912, First predoctoral Fellow of the Geo- examination of the field relations and test- season in British Columbia, in charge of his physical laboratory: Earth Sciences History, v. 11, ing the new principles with additional p. 45–55. ■ own field party, he decided to join the observations; and (6) reiteration of the Geophysical Laboratory staff, arriving September 1, 1912 (Yoder, 1992).
Critical Mineral Systems Walcott Biography To Be Published Plagioclase is the most abundant mineral in GSA original Fellow and 13th president Charles Doolittle Walcott is the subject of a biography Earth’s crust, so Bowen next undertook a by Ellis L. Yochelson; it will be published in June. Yochelson’s Rock Star profile of Walcott, a study of the two-component system albite- famous paleobiologist and biostratigrapher, was in the January 1996 issue of GSA Today. The anorthite. That system, studied earlier by book covers Walcott’s life from birth in 1850 until 1907, when he resigned as third director of Day, Allen, and Iddings (1905), was the the U.S. Geological Survey to become secretary of the Smithsonian Institution. subject of the first official publication of the Geophysical Laboratory. They had been The book is available from Kent State University Press, P.O. Box 5190, Kent, OH 44242 able to determine the melting temperature (not available through GSA Publication Sales). Charles Doolittle Walcott, Paleontologist is available at the prepublication price of $40, including postage and handling, for a limited only from An100 to An26.1 Ab73.9. Kinetic problems prohibited their measuring the time (after July 31, 1998, the price will be $53). All orders must include payment and the solidus temperature with the cooling-curve title of the book; Ohio residents add 6.25% sales tax.
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