In Memoriam
Harold W. Krueger (1935 - 1997)

Harold W. Krueger, a founder and owner of Geochron Laboratories of Cambridge, Massachusetts, died August 10, 1997, at the age of 62, after losing a three-year battle with cancer.

Born in St. James, Minnesota, Hal graduated with honors from the University of Minnesota with a Bachelor of Science in Geological Engineering in 1957 and a Master of Science in Geology in 1959. Hal's Masters work was in K-Ar dating, concentrating on rocks of the Precambrian of Minnesota and southern Ontario. He began a doctoral program in isotope geochemistry at the Massachusetts Institute of Technology in 1959, but soon left to found Geochron Laboratories along with three partners in 1960.

Geochron Laboratories, which began as a public stock company, was one of the first commercial laboratories to offer geological isotope analyses and it is the only successful one to have been started independently, without a close university association. The early years at Geochron were financially difficult, and after the first year only Hal, of the four original founders, was still involved with the company.

The first analytical service Hal offered through Geochron was the K-Ar dating of rocks and minerals. Geochron was the first commercial laboratory in the world to offer this service. In 1964, he added radiocarbon analyses to his services, and in 1969 stable isotope ratio analyses; again Hal was the first to offer these latter analyses on a commercial basis. Strontium isotope and tritium analyses were later added to his list of services. In 1967, he negotiated a merger with Orion Research Corporation. A few years later, Hal personally purchased Geochron from Orion, establishing his own corporation, Krueger Enterprises, Inc., as Geochron's legal owner, but still operating under the trade name "Geochron Laboratories".

During his 37 years with Geochron Labs, first as Technical Director, and then as President and owner, Hal devoted much of his time to studying New England geology and geochronology and pioneering the use of stable isotope analyses to identifying adulteration of foods, evaluating metabolic processes in humans and animals, determining the dietary composition of human bone, and in characterizing pollutants and determining their origins and flow patterns. As a consultant, he spent time in Morocco re-evaluating the geology of that country and its' relation to the opening of the Atlantic during the Mesozoic; in Indonesia evaluating the abilities and needs of the Indonesian Geological Survey; in Puerto Rico studying groundwater flows at a major waste repository; and at Yucca Flats, Nevada, as one of the first investigators examining the proposed nuclear waste repository site.

Hal's first love was laboratory work, and he preferred to spend as much time in the lab as possible. Over the years, he took a keen interest in the work of many of his clients, who, as a result, became his personal friends. Hal was a scrupulous investigator who like to paraphrase an old saying into "The evil is in the details". This may be one reason that he chose as his personal line of investigation the radiocarbon dating of bones - a difficult material to work with by the 14C method - which was later expanded to include the carbon and nitrogen stable isotope analyses of bones and bone components for dietary studies, using both bone collagen and bone apatite. He showed the feasibility and usefulness of this method through a series of laboratory and natural experiments.

Hal delighted in having both undergraduate and graduate students come to Geochron to use his facilities in their research work, and was more than generous with his time in assisting and instructing them in many of the finer details of the work. Hal devoted much of his time and that of his staff to hosting instructional tours for student groups, ranging from high school to graduate students. Shortly after Geochron was founded, he instituted the annual Geochron Research Awards Program, under which graduate students are awarded free analytical services, the recipients being chosen on the basis of the research proposals they submit for consideration. This program is still active after 37 years.

Although he was failing rapidly, Hal continued to come to the lab for at least a few hours a day up until two weeks before his death. He had the foresight to ensure the continuance of his laboratory, and Geochron continues to strive to provide the quality of service that Hal's friends, colleagues, and clients have come to expect. He leaves two sons, Dana and Scot, and a daughter, Lela. We have lost a good scientist, a great colleague, and a close friend.



Selected Bibliography

1961	Goldich, S.S., Nier, A.O., Baadsgaard, H., Hoffman, J.H., and Krueger, H.W. The Precambrian Geology and Geochronology of Minnesota. University of Minnesota, Minnesota Geological Survey Bulletin 41.
1965	Krueger, H.W. The Preservation and Dating of Collagen in Ancient Bones. Proceedings of the 6th International Conference on Radiocarbon and Tritium Dating, Pullman, WA USAEC Conf-650652 (332-337).
1970	Zartman, R.E., Hurley, P.M., Krueger, H.W., and Giletti, B.J. A Permian Disturbance of K-Ar Radiometric Ages in New England: Its Occurrence and Cause. Geological Survey of America Bulletin 8 (3359-3374).
1976	Lyons, P.C. and Krueger, H.W. Petrology, Chemistry, and Age of the Rattlesnake Pluton and Implications for Other Alkalic Granite Plutons of Southern New England. Geological Society of American Memoir 146 (71-102).
1980	Doner, L.W., Krueger, H.W., and Reesman, R.H. Isotopic Composition of Carbon in Apple Juice. Agricultural and Food Chemistry 28 (362).
1981	Sullivan, C.H. and Krueger, H.W. Carbon Isotope Analysis of Separate Chemical Phases in Modern Fossil Bone. Nature 292 (333-335).
1982	Krueger, H.W. and Reesman, R.H. Carbon Isotope Analyses in Food Technology. Mass Spectrometry Reviews 1 (205-236).
1983	Krueger, D.A. and Krueger, H.W. Carbon Isotopes in Vanillin and the Detection of Falsified "Natural" Vanillin. Agricultural and Food Chemistry 31 (1265-1268).
1983	Sullivan, C.H. and Krueger, H.W. Carbon Isotope Ratios of Bone Apatite and Animal Diet Reconstruction. Nature 301 (177-178).
1984	Krueger, D.A. and Krueger, H.W. Comparison of Two Methods for Determining Intramolecular 13C/12C Ratios of Acetic Acid. Biomedical Mass Spectrometry 11 (472-474).
1984	Krueger, H.W. and Sullivan, C.H. Models for Carbon Isotope Fractionation Between Diet and Bone. American Chemical Society Symposium Series, Stable Isotopes In Nutrition 258 (205-220).
1985	Martin, G.E., Krueger, H.W., and Burggraff, J.M. Radiocarbon 14C Differentiation of Sparkling and Carbonated Wines. Journal of the Association of Official Analytical Chemists 68 (440-443).
1989	Ericson, J.E., West, M., Sullivan, C.H., and Krueger, H.W. The Development of Maize Agriculture in the Viru Valley, Peru. The Chemistry of Prehistoric Human Bone, Cambridge University Press, Chapter 4, (68-104).
1989	Spies, R.B., Krueger, H.W., Ireland, R., and Rice, Jr., D.W. Stable Isotope Ratios and Contaminant Concentrations in a Sewage-Distorted Food Web. Marine Ecology Progress Series 54 (157-170).
1991	Krueger, H.W. Exchange of Carbon with Biological Apatite. Journal of Archaeological Science 18 (355-361).
1992	Eby, G.N., Krueger, H.W., and Creasy, J.W. Geology, Geochronology, and Geochemistry of the White Mountain Batholith, New Hampshire. Geological Society of America Special Paper 268 (379-397).