Stable Isotope Geochemistry of Rocks and Minerals

Abstract

Modern stable isotope geochemistry began with the classic paper of Harold Urey, published in 1947 and entitled Thermodynamic Properties of Isotopic Substances. For several light elements, Prof. Urey calculated isotopic fractionation factors between species of geochemical interest and, based on a suggestion by Prof. P. Niggliin ZUrich, proposed that paleotemperatures of the ancient oceans might be determined by analysis of the oxygen isotope compositions of carbonate shell materials. Within a few years, the research group that Prof. Urey had assembled at the University of Chicago was successful both in increasing the precision of the Nier isotope ratio mass spectrometer by the necessary factor of 10, and in establishing an oxygen isotope paleotemperature scale. The Chicago group made studies of oxygen isotope variations in rocks and minerals and in natural waters, the carbon isotope variations in nature, and the hydrogen isotope variations in natural waters andin rocks and minerals. Early studies of sulfur isotope variations in nature were made by Profs. H. Thode in Canada and M. Trofimov in the Soviet Union. Toward the end of the 1950\textquoteright{}s, Prof. S. Epstein\textquoteright{}s group at Caltech showed that oxygen isotope fractionations between coexisting minerals in higher temperature rocks were indeed large enough to be useful in geothermometry and opened up a powerful field of geochemical research.