Distinguished Professor, Biology
Distinguished Professor, Geology & Geophysics
My research is in geochemistry of processes occurring at near Earth's surface and the geological record of ecological change. My research includes the isotope physiology and diets of modern mammals as well as the history of diets of different mammalian lineages extending over millions of years. I am also interested in the geology of Old World paleoanthropologic sites, such as are found in the Turkana Basin in East Africa and other Rif Valley sites. I study modern soils, lakes, and ecosystems in an effort to apply isotope systematics to understand the evolution of ecosystems, monsoons, and the atmosphere over geological time scales. By using isotopes produced by cosmic rays in situ in rocks my research group studies the evolution of the landscapes over the last 1 million years. I am also involved in environmental studies, including the use of tritium and helium as hydrological tracers, and in understanding contaminant migration in surface or groundwaters.