La fédération
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Research
My research concerns the study of fluid-solid reactions (here solids include minerals, glasses, rocks) that occur in terrestrial settings, where the focus has been the Earth’s surface and upper crust. When solids contact reactive aqueous fluids chemical and physical alteration processes take place, in particular dissolution and precipitation reactions. My research has shown that these reactions are generally controlled by interfacial processes that occur in a thin interfacial fluid film between the solid and the solvent phase, and very importantly, ultimately affecting the macroscopic behavior of the system. On an even larger scale, the macroscopic processes characterizing water-rock interactions (WRI) play a key role in controlling the overall balance of elements in the crust, the chemical composition of natural waters, the adsorption and sequestration of metals, soil formation and fertility, and global climate regulation through CO2 consumption. WRI is also important for industrial applications, such as the storage of nuclear and industrial waste, CO2 sequestration in geological environments, underground H2 storage, and geothermal energy. Based on a large international collaboration, I have recently started to examine water-rock interactions on grains from the asteroid Ryugu that were retrieved by the JAXA Hyabusa2 mission. This has provided a unique window on WRI processes that were operative while the Solar System was forming 4.6 billion years ago. This includes the chemical evolution of organic matter and the formation of hydrous clay phases in a pristine extraterrestrial environment. These processes ultimately have important implications for the evolution of many types of celestial bodies (asteroids, icy moons, comets, planetesimals), but also for the habitability of early Earth.
To summarize the big picture of my research, the overall aim is to obtain specific data needed to develop rate laws and models for quantifying reactivity and elucidating mechanistic pathways of alteration reactions undergone by minerals, glasses, and rocks in contact with aqueous fluids. Taken together, they provide a better understanding of physical and chemical instabilities in various terrestrial and extraterrestrial environments at different spatial and temporal scales.
To accomplish these goals, I use a “macroscopic-microscopic” approach to study WRI reactions at multiple scales, ranging from aqueous kinetic data derived from macroscopic laboratory experiments to physical and chemical measurements of fluid-solid interfaces at the µm-scale down to the atomic level (Å). This dual approach allows for a better understanding of the link between myriad processes operating at very different scales. Measurements of physical and chemical changes at interfaces are based on a wide range of analytical techniques, including advanced analytical electron microscopy (TEM), atom probe tomography, nano & ToF-SIMS, and electron spectroscopy.
To summarize the big picture of my research, the overall aim is to obtain specific data needed to develop rate laws and models for quantifying reactivity and elucidating mechanistic pathways of alteration reactions undergone by minerals, glasses, and rocks in contact with aqueous fluids. Taken together, they provide a better understanding of physical and chemical instabilities in various terrestrial and extraterrestrial environments at different spatial and temporal scales.
To accomplish these goals, I use a “macroscopic-microscopic” approach to study WRI reactions at multiple scales, ranging from aqueous kinetic data derived from macroscopic laboratory experiments to physical and chemical measurements of fluid-solid interfaces at the µm-scale down to the atomic level (Å). This dual approach allows for a better understanding of the link between myriad processes operating at very different scales. Measurements of physical and chemical changes at interfaces are based on a wide range of analytical techniques, including advanced analytical electron microscopy (TEM), atom probe tomography, nano & ToF-SIMS, and electron spectroscopy.