Background

Norman Levi Bowen was born on June 21, 1887, in Kingston, Ontario. He was the son of William Alfred Bowen and Elizabeth McCormick, English immigrants.

Education

Norman Bowen studied chemistry and mineralogy at Queen's University and received the honors degree of M. A. in 1907. For the next six summers, Bowen worked in the field for the Ontario Bureau of Mines and the Canadian Geological Survey, most notably in British Columbia with R. A. Daly in 1911. Bowen returned to Queen's University in 1907 to enter the School of Mining, receiving the B. S. in 1909. In 1909 he entered the Massachusetts Institute of Technology.

Career

The geophysical laboratory had been founded in 1906 under the direction of Arthur L. Day for the specific purpose of experimentally defining the physicochemical parameters governing geologic processes, particularly the formation of igneous rocks. A lifelong association with the Geophysical Laboratory of the Carnegie Institution of Washington, D. C. , began in 1910, when Bowen, who had entered the Massachusetts Institute of Technology the previous year, experimentally defined the conditions of crystallization for the pair of minerals nepheline-anorthite (expressed in the form of the phase-equilibrium diagram).

In 1910, although a well-developed body of theoretical physical chemistrywas at hand, almost nothing was known of the actual temperatures and pressures at which real rocks are formed.

Classical methods of observation in the field and under the microscope were the basis for the inference of geologic processes, but their relation to the laws of physical chemistry was unknown. Harry Rosenbusch of Heidelberg headed the petrologic school that sought in the rock specimen itself the evidence of its origin and evolution; the method was essentially a posteriori. J. H. L. Vogt found artificially produced assemblages of silicate minerals in metallurgical slags.

In his student paper "On the Order of Crystallization in Igneous Rocks" (1912), Bowen employed Rosenbusch's classicalmethod even while disputing his conclusions. Bowen's early papers mention the influences of Vogt and the metallurgist Cecil H. Desch, as well as Alfred Harker and the petrologists Louis V. Pirsson and Joseph P. Iddings.

During the next forty-six years, alone and with other geologists and physical chemists G. W. Morey, J. W. Grieg, F. C. Kracek, E. Posnjak, O. R. Tuttle and J. F. Schairer Bowen established the phase diagrams for the principalcomponents of igneous rocks and applied them to develop the modern magmatic theory of petrogenesis. In doing so he made Washington, with its twin laboratories of the Carnegie Institution and the U. S. Geological Survey, the world center of experimental petrology.

Bowen's first phase diagram, nepheline-anorthite, was the basis for his dissertation at the Massachusetts Institute of Technology in 1912.

His Princeton lectures, published in 1928 as The Evolution of the Igneous Rocks, embodied a complete physicochemical theory of magmatic differentiation based on more than fifty of his articles that had been published since 1913, the majority being phase diagrams of silicate systems. No other twentieth-century work exerted a comparable influence on petrology.

In 1915, Bowen discussed laboratory and field evidence for crystallization differentiation in silicate liquids through the gravity settling of early-formed olivine crystals and the floating of silica minerals, a mechanism proposed also by Darwin.

He died in Washington, D. C.

Achievements

• Norman Bowen was a professor of geology at Queen's University from 1918 to 1920 and professor of petrology at the University of Chicago from 1937 to 1947. The rest of his career was spent almost exclusively at the geophysical laboratory of the Carnegie Institution. He wrote 18 papers with J. F. Schairer, the last appearing in 1956. He was president of the Mineralogical Society of America in 1937 and of the Geological Society of America in 1946. He was also an honorable member of the National Academy of Sciences. The "Bowen volume" of the American Journal of Science was dedicated to him in 1952 on his retirement. Preparation of ternary diagrams (three mineral components) by Bowen and Olaf Anderson extended the method from mineral pairs to complete, if ideal, rock systems. Bowen was awarded the Penrose Medal of the Geological Society of America in 1941 and served as their president in 1945. The Norman L. Bowen Award, awarded annually by the American Geophysical Union, is named in his honour. In addition to the intuitive understanding of the field geologist, Bowen had the ability to develop and apply a silicate physical chemistry to the intrusive rocks. The rare personal qualities that enabled him to surround himself with so many major collaborators and to lead the Carnegie Geophysical Laboratory to preeminence, coupled with his technical and intellectual virtuosity, gave rise to the modern magmatic school of petrology. The astronauts of Apollo 17 named a small lunar crater after him.

Works

More photos

• book

  • Evolution of the Igneous Rocks

    (For New condition books; You will be the first to open th...)

  • Origin of Granite in Light of the Experimental Studies in the System
  • Origin of Granite in the Light of Experimental Studies in the System NaAlSi3O8-KAlSi3O8-SiO2-H2O

Views

While continuing as an assistant petrologist at the geophysical laboratory, Bowen undertook the study of the plagioclase feldspars, the most important mineral component of igneous rocks. In two months Bowen fused, quenched, and analyzed seventy-five separate silicate charges. He showed that the plagioclase feldspars were miscible in all proportions, and he established that the particular plagioclase (proportion of soda to lime) crystallizing out was determined solely by temperature.

In melting silicate charges of a given composition, Bowen used the lowest temperature at which any glass could be obtained to determine the position of the melting-point curve (called the solidus) and the temperature of the first appearance of crystals in cooling down a silicate fusion to determine the freezing-point curve (liquidus). The results were checked against runs with natural crystals and against the newly published curves of Esper S. Larsen, Jr. , for optical determination of the composition of plagioclase glass.

Bowen explained the plagioclase solid solution by using the crystal structure theory of William Barlow and William J. Pope, anticipating the first X-ray determination of any crystal structure by only months. In this classic paper of crystal chemistry, "The Melting Phenomena of the Plagioclase Feldspars" (1913), Bowen accounted for the association of different igneous rock types by proposing the separation of crystals and liquid at various stages of the crystallization of a magma. The work contained all the essential ideas of modern magmatic petrology.

Also in 1915, Bowen published the complete theory as "The Later Stages of the Evolution of the Igneous Rocks, " accounting for the differentiation of magmas by the process that he later named "fractional crystallization. " The assimilation of country rock by fusion with a magma, his laboratory results showed, would affect the quantities of various rocks produced but not their compositions. The temperature and composition of the final magma depended upon the events of its history, such as the settling, flotation, and filtration of early-formed crystals.

In 1917, Bowen explained the problem of monomineral rocks, such as the anorthosites, as segregations from a gabbroic melt. In the polemical "Crystallization-Differentiation in Igneous Magmas" (1919), he asserted the authority of the phase diagram over hypotheses derived from field studies and coined the term "filterpress" for processes that he considered in detail in "Differentiation by Deformation" (1920).

In "The Reaction Principle in Petrogenesis" (1922), Bowen asserted that the two principal reaction series of silicate petrology, the continuous plagioclase and the discontinuous ferromagnesian series, together forced an order of crystallization confirming Rosenbusch's empirical order and contrary to that predicted by the law of massaction.

In "The Behavior of Inclusions in Igneous Magmas" (1922), he showed how the assimilation of foreign matter by a magma affects principally rates of crystallization and relative amounts rather than the mineralogy of the differentiates.

Membership

Bowen was elected a Foreign Member of the Royal Society (ForMemRS) of London in 1949. He was also a member of the Mineralogical Society of America and of the Geological Society of America.

Connections

On October 3, 1911, Norman Levi Bowen married Mary Lamont. They had one daughter.

Father:

William Alfred Bowen

Mother:

Elizabeth McCormick

Wife:

Mary Lamont

colleague:

George Washington Morey

American geochemist, physical chemist, mineralogist, petrologist

colleague:

O. R. Tuttle

geochemist

colleague:

E. Posnjak

geochemist

colleague:

F. C. Kracek

geochemist

colleague:

J. W. Grieg

American geochemist

colleague:

John Frank Schairer

American geochemist, mineralogist, petrologist

associate:

Arthur Louis Day

American geophysicist

References

• Biographical Memoirs Of Fellows Of The Royal Society, 1955 Volume I