The 2009 Louis Néel Medal is awarded to Yves Guéguen in recognition of his outstanding contributions to mineral and rock physics, including work on the deformation of the Earth’s mantle and the complex interplay of physical, mechanical and transport properties of crustal rocks.
Yves Gueguen is an internationally leading expert in the field of rock physics. Since 1996 he is Professor of Geophysics and Head of the Laboratoire de Géologie at Ecole Normale Supérieure in Paris. In his scientific career, Yves has covered a broad area including experimental, theoretical and field studies that reach from high-temperature deformation and elastic properties of mantle materials to the mechanics and transport behavior of sedimentary rocks. As a CNRS fellow, Yves finished his doctorate in Nantes in 1974 already deeply involved in the study of mantle materials. At the time, Nantes was one of the hotbeds of research on mantle rocks. Adolphe Nicolas and his group contributed much to our understanding of mantle dynamics by successfully combining microstructure observations with the principles and methods of solid-state physics and material science to decipher the prevailing processes of rock deformation. As an important part of his work from this period, Yves and coauthor Anne-Marie Boullier published a series of seminal papers on the superplastic deformation in high-strain mylonite shear zones from lower crust and upper mantle. This was followed by a number of well-received publications studying dislocation activity and plastic flow of olivine including studies of naturally and experimentally deformed rocks.
Shortly after finishing his These d’Etat still in Nantes, Yves received his appointment to Professor of Geophysics at the University in Strasbourg in 1981. The move to Strasbourg was also associated with a shift in focus of Yves’ main research interests from high-temperature plastic flow in the mantle towards mechanical and transport properties of crustal rocks. In Strasbourg, Yves and his colleagues established a highly-reputed and productive research group from which several of his graduate students (Christian David, Thierry Reuschle, Patrick Baud and others) have since emerged as leading scientists with their own laboratories. After 12 years in Strasbourg, Yves moved to Rennes for a brief period before accepting the position of professor and director at Ecole Normale Supérieure in Paris. Again, he quickly managed to establish experimental and theoretical rock physics as a new research area at ENS while at the same time advising a constant flow of excellent graduate students, some of whom are now prominent members of the group: Alex Schubnel, Jouel Sarout and Jerome Fortin.
Over the years, Yves and his students published many outstanding papers on the mechanics of fluid-saturated rocks using experimental and theoretical studies. These contributions are of fundamental importance for the mechanics of seismogenic faults and transport processes in reservoir rocks. Combining fracture and damage mechanics with percolation theory, network modeling and advanced techniques of microstructure analysis, Yves contributed ground-breaking new results on such diverse topics as permeability and pore shape evolution, electrical conductivity, poroelasticity and scale effects in rocks. Yves and his coauthor Victor Palciauskas have also authored an excellent and well-received textbook on rock physics that stands out as a clear and comprehensive introduction to the field. In addition to being an international leader in rock physics and an excellent advisor to his students, Yves has also provided significant service to the community, for example in serving as a journal editor, in establishing and coordinating international research programs, and over many years, encouraging collaboration between research groups in Europe.