Microscale C-O-S isotope signatures record microbial sulfate reduction in ancient deep subsurface pyrite–calcite–barite assemblages

Runge, Eric; Fichtner, Vanessa; Tillberg, Mikael; Whitehouse, Martin; Drake, Henrik

doi:10.5194/bg-23-7893-2026

Articles | Volume 23, issue 21

https://doi.org/10.5194/bg-23-7893-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-23-7893-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 21

Research article

|

06 Nov 2026

Research article |

| 06 Nov 2026

Microscale C-O-S isotope signatures record microbial sulfate reduction in ancient deep subsurface pyrite–calcite–barite assemblages

Eric Runge, Vanessa Fichtner, Mikael Tillberg, Martin Whitehouse, and Henrik Drake

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https://doi.org/10.5194/bg-23-7893-2026-supplement

Data sets

Compilation of C-O-S stable isotope data from ancient subsurface calcite-pyrite-barite assemblages (Southern Sweden) Eric Runge et al. https://doi.org/10.5281/zenodo.22041131

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Short summary

We investigated past microbial processes in the deep continental subsurface by stable C-O-S isotope analyses of fracture-hosted pyrite-calcite-barite assemblages. These minerals show signatures of two different pathways of microbial sulfate reduction, linked to local hydrogeochemical conditions. We further suggest that these local conditions are also crucial in controlling the preservation of microbial biosignatures in deep subsurface mineral assemblages.