1,2,4,2,3,4- 1Université Marie et Louis Pasteur, CNRS, Chrono-environnement (UMR 6249), F-25000 Besançon, France
- 2Department of Geosciences, University of Bremen, Klagenfurter Straße 2-4, 28359 Bremen, Germany
- 3MARUM Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
- 4Department of Bological Geological and Environmental Sciences, University of Bologna, 40126 Bologna, Italy
Volcanic basins play a central role in the exchange of volatiles between the lithosphere, hydrosphere, atmosphere and biosphere. The intrusion of magmas into sedimentary basins induces complex interactions between magma, sediments and fluids, profoundly modifying the biogeochemical cycles of carbon and sulphur. These phenomena are known to have contributed to major climatic and biological crises throughout Earth's history, but the mechanisms by which volatiles are partially trapped are still poorly understood.
This study (Cheviet et al. 2023; 2025) focuses on magma-sediment-fluid interaction processes and their consequences for the mobilisation and sequestration of carbon and sulphur in the Guaymas Basin (Gulf of California), a young system where basaltic sills were emplaced in unconsolidated sediments rich in organic matter and pore water. Three levels of interaction have been identified: (1) contact metamorphism, (2) magmatic contamination (3) late hydrothermal circulation. Taken together, these processes allow several hundred thousand tonnes of sulphur and large quantities of carbon to be stored locally. On a basin-wide scale, these interactions transform sills and their direct surroundings in volatile traps, modifying the global balance of greenhouse gases emitted during magmatic intrusions. This study shows that, contrary to the classic paradigm of complete degassing into the atmosphere, a significant proportion of volatiles can be sequestered in magmatic and metamorphic rocks over the long term. These magma-sediment-fluid processes will be studied at basin scale within the framework of the DEGAS project (ERC-2024-CoG).
Cheviet, A., Buatier, M., Choulet, F., Galerne, C., Riboulleau, A., Aiello, I., Marsaglia, K. M., and Höfig, T. W.: Contact metamorphic reactions and fluid–rock interactions related to magmatic sill intrusion in the Guaymas Basin, Eur. J. Mineral., 35, 987–1007, https://doi.org/10.5194/ejm-35-987-2023, 2023.
Cheviet A., Goncalves P., , Choulet F., Bach W., Riboulleau A., Vennemann T., Buatier M.: Carbon trapping during contact metamorphism in magmatic basins. Contributions to Mineralogy and Petrology https://doi.org/10.1007/s00410-025-02262-0, 2025.
ERC-2024-CoG “Deconvolving sources and sinks of carbon and sulfur in magmas to reconstruct DEGASsing from Large Igneous Provinces” https://doi.org/10.3030/101170872
How to cite: Cheviet, A., Buatier, M., Choulet, F., Galerne, C., Bach, W., and Callegaro, S.: Impact of magmatic activity and magma-sediment-fluid interactionson the transfer and sequestration of volatiles in the Guaymas Basin, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12527, https://doi.org/10.5194/egusphere-egu26-12527, 2026.
