Summary: The increasing global demand for critical elements (CEs), such as metals (Al, Co, Cu, Li, etc.) and He and H2, has positioned geothermal brines as potential next-generation resources. Exploring high-enthalpy hydrothermal systems as a secondary, domestic source of CE is a rapidly evolving frontier essential for developing technologies used for the energy transition. However, the fundamental mechanisms that control CE enrichment and their transport within magmatic-hydrothermal systems remain poorly constrained, complicating sustainable resource exploitation.

This session invites interdisciplinary contributions that use geochemical and isotopic tracers to unravel the origins and mobilization of CEs in different geological environments and tectonic contexts.  We seek original contributions on CE source identification using multi-isotopic approaches; laboratory experiments to determine partitioning coefficients of CE between fluids and rocks or melts; kinetic and thermodynamic investigations to unravel how temperature, pH, and redox control CE leaching, transport, and selective precipitation; reservoir geology, migration processes and their impact on the accumulation of CE; data mining and predictive modeling applying multivariate statistical analysis and machine learning to build predictive models of CE distribution in underexplored environments.

Summary: Geological carbon storage is considered a key technology for reducing atmospheric carbon dioxide (CO₂) emissions and achieving long-term carbon neutrality goals. The injection and storage of CO₂ in deep geological formations involve complex multiphase flow, geochemical reactions, and mineral transformations, where WRI plays a critical role in controlling CO₂ migration, trapping mechanisms, storage capacity, and long-term stability. The dissolution of CO₂ into formation water, acid–rock reactions, mineral dissolution and precipitation, and changes in porosity and permeability collectively influence the evolution of storage reservoirs and the effectiveness of carbon sequestration. Understanding these coupled hydrogeological and geochemical processes is essential for predicting reservoir performance and ensuring safe and sustainable CO₂ storage.

This session welcomes contributions that investigate: (i) groundwater discharge and chemical evolution in groundwater-dependent ecosystems; (ii) the impacts of groundwater quality changes on ecosystems; (iii) biogeochemical processes linking groundwater systems and ecosystem functioning. We encourage submissions from diverse geographic regions and research communities addressing the complex relationships between groundwater geochemistry, ecological health, and environmental sustainability.

Summary: The migration behavior of radionuclides in geological environments is a critical concern for environmental safety, nuclear energy development, radioactive waste disposal, and the long-term management of contaminated sites. The transport, retention, and transformation of radionuclides are controlled by complex interactions among groundwater flow, mineral surfaces, aqueous geochemistry, and microbial processes. Natural geological barriers, including minerals, fractures, and sedimentary formations, play important roles in regulating radionuclide mobility through processes such as adsorption, ion exchange, precipitation, dissolution, and redox transformation. In engineered systems, understanding radionuclide behavior and its interaction with barrier materials is essential for evaluating the performance and safety of radioactive waste repositories and other nuclear-related facilities.

This session welcomes contributions that investigate: (i) geochemical processes controlling radionuclide speciation, mobility, and long-term fate in natural and engineered environments; (ii) experimental, isotopic, and spectroscopic approaches for understanding radionuclide–mineral–microbe interactions; (iii) reactive transport modeling for predicting radionuclide migration under changing environmental conditions. We encourage submissions addressing fundamental mechanisms, site characterization, safety assessment, and innovative strategies for managing radionuclide-related environmental challenges across diverse geological settings.

Summary: The increasing demand for critical minerals driven by renewable energy technologies, advanced manufacturing, and global energy transitions has intensified mineral exploration and mining activities worldwide. The extraction, processing, and weathering of mineral resources significantly modify geological and hydrological environments, leading to complex water–rock interactions and the release, transport, and transformation of potentially harmful elements. Environmental geochemical processes associated with mining, including sulfide oxidation, acid mine drainage formation, mineral dissolution, secondary mineral precipitation, and contaminant attenuation, play key roles in controlling the evolution of surface water and groundwater quality. Understanding these processes is essential for balancing critical mineral supply with environmental protection and sustainable resource management.

This session welcomes contributions that investigate: (i) geochemical processes controlling the formation, alteration, and weathering of critical mineral deposits; (ii) water–rock interactions associated with mining activities and their impacts on environmental quality; (iii) the mobility, fate, and remediation of potentially toxic elements during mining. We encourage submissions addressing the links between mineral resources, geological processes, and environmental sustainability across diverse mining regions and geological settings worldwide.