Fluid-rock interactions in the Earth

Volatile cycling on Earth, determined from their inventory and distribution within the silicate envelops, involves fluid-rock interactions from the surface down to subduction zones. Alteration processes, pedogenesis, and diagenetic processes have a strong impact on the cycles of trace metals or radionuclides, which are the subject of numerous projects developed within MINENV and PALM. There is also a strong research interest and expertise in the laboratory on deep geological fluids and their connection to surface processes. An approach of fluid-rock interactions during metamorphism (T > 200-300°C) from subduction to contact metamorphism, and their implications on the speciation of C-bearing phases (graphitic carbon, carbonates) using Raman spectroscopic tools has been developed by the ROCKS group. Field-based petrological and geochemical studies are applied to fluid-rock interactions and metasomatism controlling the storage and mobility of deep C-O-H fluids from different geodynamic settings (subduction, continental and oceanic lithosphere), and their contribution to global H and C cycles (MP³). More specifically, the formation of molecular hydrogen and abiotic hydrocarbons in ultramafic systems is studied via a multi-tool approach involving collaborations with several other teams for the mineralogical characterization of natural samples (MINENV, PALM, MIMABADI) and the numerical simulation of natural processes using ab initio techniques (TQM).