Professor Hugh O'Neill FRS
Associate Director, Research School of Earth Sciences, Australian National University
Hugh O'Neill has made fundamental contributions to the study of mineral equilibria and their application to understanding planetary processes. His science is distinguished by his use of careful laboratory measurements of the physicochemical properties of geomaterials to address large-scale geological problems. These problems include estimating the chemical composition of the Earth and its major subdivisions, the core, the mantle and the crust; understanding how the Earth differs from other possible planetary compositions; studies of the redox state of the Earth's mantle; core formation in the Earth and the nature of the light element(s) in the core; the origin of the Earth-Moon system by giant impact; and partial melting in the Earth's upper mantle and its relationships with global tectonics and Earth history. An understanding of such complex issues demands that the fundamental principles be addressed, and this perspective has guided his extensive achievements in experimental petrology.