EGU2020-2094
https://doi.org/10.5194/egusphere-egu2020-2094
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The carbon-isotope signature of diagenetic carbonates

Patrick Meister1 and Carolina Reyes2
Patrick Meister and Carolina Reyes
  • 1University of Vienna, Department of Geodynamics and Sedimentology, Vienna, Austria (patrick.meister@univie.ac.at)
  • 2University of Vienna, Department of Environmental Geosciences, Vienna, Austria (creyes6@gmail.com)

Diagenetic carbonates often show large variations in their carbon isotope compositions. Variations are mainly the result of isotope fractionation effects during microbial metabolic processes, and these processes themselves may induce carbonate formation. Inorganic carbon from dissimilatory microbial activity shows negative carbon isotope values (d13C), in particular if methane is used as a carbon source. In turn, inorganic carbon produced during methanogenesis shows positive d13C values. The range of isotope values preserved in the carbonate phase ultimately depends on the reservoir sizes, diffusive mixing of different carbon sources, and episodic formation of carbonate (Meister et al., 2019; Meister and Reyes, 2019). The carbon-isotope signature of diagenetic carbonates therefore represents an archive of past biogeochemical activity in the subsurface.

 

References:

Meister, P. and Reyes, C. (2019) The carbon-isotope record of the sub-seafloor biosphere. In: "Tracking the Deep Biosphere through Time" (Eds. H. Drake, M. Ivarsson, C. Heim), Geosciences 9, 507, 1-25. https://doi:10.3390/geosciences9120507

Meister, P., Liu, B., Khalili, A., Böttcher, M.E., and Jørgensen, B.B. (2019) Factors controlling the carbon isotope composition of dissolved inorganic carbon and methane in marine porewater: An evaluation by reactive-transport modelling. J. Marine Systems 200, 103227, 1-18. https://doi.org/10.1016/j.jmarsys.2019.103227

 

 

How to cite: Meister, P. and Reyes, C.: The carbon-isotope signature of diagenetic carbonates, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2094, https://doi.org/10.5194/egusphere-egu2020-2094, 2020

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