Geological CO2 contributions quantified by high-temporal resolution carbon stable isotope monitoring in a salt mine
- 1Department of Geography and Geosciences, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
- 2K+S Aktiengesellschaft, Kassel, Germany.
- 3Inorganic and Isotope Geochemistry, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany.
CO2 emissions from geological sources have been recognized as an important input to the global carbon cycle. In regions without active volcanism, mines provide an extraordinary opportunity to observe dynamics of geogenic degassing close to its source.
High temporal resolution of stable carbon isotopes allows to outline temporal and interdependent dynamics of geogenic CO2 contributions. We present data from an active underground salt mine in central Germany that were collected on site with a field-deployed laser isotope spectrometer.
Throughout the 34-day measurement period, total CO2 concentrations varied between 805 ppmV (5th percentile) and 1370 ppmV (95th percentile). With a 400 ppm atmospheric background concentration, an isotope mixing model enabled the separation of geogenic (16–27 %) from highly dynamic contributions from anthropogenic CO2-sources (21–54 %). The geogenic fraction was inversely correlated to established CO2 concentrations that were driven by anthropogenic CO2 emissions within the mine. This indicates gradient-driven diffusion along microcracks.
Read more about this work in our open access publication in Scientific Reports at: http://rdcu.be/cblTz
How to cite: Frank, A. H., van Geldern, R., Myrttinen, A., Zimmer, M., Barth, J. A. C., and Strauch, B.: Geological CO2 contributions quantified by high-temporal resolution carbon stable isotope monitoring in a salt mine, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13234, https://doi.org/10.5194/egusphere-egu21-13234, 2021.
