Robert Garrels

Robert Minard Garrels (August 24, 1916 – March 8, 1988) was an American geochemist. Garrels applied experimental physical chemistry data and techniques to geology and geochemistry problems. The book Solutions, Minerals, and Equilibria co-authored in 1965 by Garrels and Charles L. Christ revolutionized aqueous geochemistry.

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Garrels earned a bachelor's degree in geology from The University of Michigan in 1937. He went on to earn an M.S. degree from Northwestern in 1939, his thesis work was on iron ores of Newfoundland in 1938. His Ph.D was awarded in 1941 based on lab studies of complex formation between lead and chloride ions in aqueous solution.

Garrels worked for the USGS during World War II and returned to teach at Northwestern until 1952. Also in 1952 he published a technical paper, "Origin and Classification of Chemical Sediments in Terms of pH and Oxidation-Reduction Potentials." with W. C. Krumbein, which was to become a classic study of sedimentary rocks from a physical chemistry viewpoint. This and following works revolutionized sedimentary and aqueous geochemistry.

He joined the USGS again for a time, but returned to academia at Harvard in 1955. He became full professor in 1957. His work and the lab he supervised at Harvard produced many classic works including the Solutions, Minerals, and Equilibria text. Here between 1960 and 1962 he along with his colleagues published the classic studies:

• "Oxidation of Pyrite by Iron Sulfate Solutions"
• "Stability of Some Carbonates at 25°C and One Atmosphere Total Pressure"
• "Control of Carbonate Solubility by Carbonate Complexes"
• "A Chemical Model for Sea Water at 25°C and One Atmosphere Total Pressure"

He returned to Northwestern in 1965 and conducted influential studies on the silicate and carbonate buffering of seawaters, the genesis of groundwaters and the theoretical treatment of irreversible reactions in geochemical processes.

In 1969 he moved to the Scripps Institution of Oceanography and later to the University of Hawaii. During this time he worked on thermodynamic properties of silicate minerals and also published "Cycling of Carbon, Sulfur, and Oxygen through Geologic Time" with Ed Perry in 1974.

In 1974 he returned to Northwestern and published important studies on the sulfur and carbon isotopic compositions of Phanerozoic rocks with Abraham Lerman and MacKenzie.

He moved to the University of South Florida in 1979 where he published "The Carbonate-Silicate Geochemical Cycle and Its Effect on Atmospheric Carbon Dioxide over the Past 100 Million Years" in 1983. He continued active while fighting cancer, publishing "Modeling Atmospheric 02 in the Global Sedimentary Redox Cycle" (1986) and "A Model for the Deposition of the Microbanded Precambrian Iron Formations." (1987)

He received many awards and honors including:

• election to the National Academy of Sciences (1961)
• president of the Geochemical Society (1962)
• the Arthur L. Day Medal of the Geological Society of America (1966)
• the Goldschmidt Award of the Geochemical Society (1973)
• the Penrose Medal of the Geological Society of America (1978)
• the Wollaston Medal of the Geological Society of London (1981)
• the Roebling Medal of the Mineralogical Society of America (1981)

Bibliography

• A Textbook of Geology, Harper's Geoscience Series (1951)
• Behavior of Colorado Plateau uranium minerals during oxidation (Trace elements investigations report) USGS (1956)
• Mineral Equilibria at Low Temperature and Pressure, Harper (1960)
• Solutions, Minerals, and Equilibria with Charles L. Christ (1965) (2nd ed. Freeman Cooper Co, 1982 and revised ed 1990) ISBN 0-86720-148-7 (1990 ed.)
• Evolution of Sedimentary Rocks with Fred Mackenzie; Norton, (1971) (ISBN 0-393-09959-8)
• Water the Web of Life with Cynthis Garrels; Norton (1972) (ISBN 0-393-09407-3)
• Chemical cycles and the global environment: Assessing human influences with Cynthia Garrels and F. T. Mackenzie W.; Kaufmann (1975) (ISBN 0-913232-29-7)
• Thermodynamic Values at Low Temperature for Natural Inorganic Materials: An Uncritical Summary, with Terri L. Woods; Oxford University Press (1986) ISBN 0-19-504888-1

References

• Biographical Memoirs V.61 (1992), The National Academies Press, by Robert A. Berner, p 195-212