Tracking CO2 mobility during magma-limestone interaction: insights from spectroscopic analysis of experiments
- 1Department of Earth Sciences, Uppsala University, Uppsala, Sweden
- 2Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
- 3School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- 4Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden
- 5Department of Geosciences, University of Oslo, Oslo, Norway
- 6Faculty of Geological Engineering, Universitas Padjajaran, Bandung, Indonesia
- 7European Plate Observing System, European Research Infrastructure Consortium, Rome, Italy
- 8Department of Geosciences, University of Padua, Padua, Italy
- 9Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia
- 10Institute of Earth and Environmental Sciences, University of Freiburg, Freiburg, Germany
Magma-limestone interaction is thought to be an important source of carbon in volcanic arc emissions (1). To better understand the production of volatiles and their behaviour in silicate melts during magma-limestone interaction, we performed Raman and FTIR spectroscopic analysis of bubbles and glasses in the products of a time-series of high pressure-temperature experiments (2). The experiments were designed to simulate entrainment and assimilation of limestone (CaCO3) xenoliths in mafic magma using starting materials from an iconic example of a limestone-hosted arc volcano (Mt. Merapi, Sunda arc, Indonesia) (3). The experimental conditions were T = 1200 °C and P = 0.5 GPa, with run-times ranging from t = 0 s to t = 300 s. Our shortest run-time experiment (t = 0 s) reveals formation of CO2-rich bubbles (± C, CO, N2, H2, H2O, CH4) in and around the magma-limestone reaction site and fast diffusion of CO32- and CO2 molecules throughout the host melt (qualitatively faster than Ca diffusion). Longer run-time experiments (up to t = 300 s) show that bubbles evolved to become larger and richer in CO2 close to the reaction site and that they grew by extracting CO2 from the surrounding melt. Magma-limestone interaction thus rapidly mobilizes CO32- andCO2 and promotes formation of compositionally evolving CO2-rich fluids, which could migrate along fractures, faults, or other fluid escape pathways to contribute to atmospheric fluxes of CO2 at volcanic arcs.
References
(1) Mason E., Edmonds M., Turchyn AV (2017) Remobilization of crustal carbon may dominate volcanic arc emissions. Science 357, 290-294, doi: 10.1126/science.aan5049
(2) Deegan FM, Troll VR, Freda C, Misiti V, Chadwick JP, McLeod CL, Davidson JP (2010) Magma-carbonate interaction processes and associated CO2 release at Merapi volcano, Indonesia: Insights from experimental petrology. Journal of Petrology 51, 1027-1051, doi:10.1093/petrology/egq010
(3) Deegan FM, Troll VR, Gertisser R, Freda C (2023) Magma-carbonate interaction at Merapi volcano. In: Gertisser R., Troll VR, Walter T, Agung Nandaka IGM, Ratdomopurbo A (Eds.) Merapi volcano: Geology, eruptive activity, and monitoring of a high-risk volcano (Volcanoes of the World Book Series). Springer Verlag, Berlin, Heidelberg, New York. Chapter 10, 291-321, doi:10.1007/978-3-031-15040-1_10
How to cite: Deegan, F., Capriolo, M., Weis, F., Callegaro, S., Troll, V., Freda, C., Misiti, V., Aradi, L., Skogby, H., Darmawan, H., and Geiger, H.: Tracking CO2 mobility during magma-limestone interaction: insights from spectroscopic analysis of experiments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7943, https://doi.org/10.5194/egusphere-egu24-7943, 2024.
