EGU23-13182, updated on 26 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mineral-trapping of greenhouse gases in Arctic glendonites

Bas van de Schootbrugge1, Martin Schobben1, Chloe Morales1, Lubos Polerecky1, Michiel Kienhuis1, Klaas Nierop1, Francien Peterse1, Nico Janssen2, Tianchen He3, Rob Newton3, Julia van Winden4, Johan Weijers4, Olaf Podlaha4, Appy Sluijs1, and Jack Middelburg1
Bas van de Schootbrugge et al.
  • 1Utrecht University, Institute of Earth Sciences, Utrecht, Netherlands (
  • 2TNO, Utrecht, Netherlands
  • 3Leeds University, Leeds, UK
  • 4Shell, Technology Centre Amsterdam, Netherlands

Fossil ikaite, preserved as the pseudomorph glendonite, occurs in vast amounts in Jurassic and Cretaceous successions in the high Arctic. Thermodynamics predict that ikaite is only stable at near-freezing temperatures and glendonite is thus widely used as a paleo-indicator of cold climate conditions, conflicting with traditional views of a very warm and equable Mesozoic greenhouse. Here, we show based on a multi-proxy investigation of Jurassic and Cretaceous glendonites from Siberia and Svalbard that this one-dimensional view detracts from their exceedingly complex biogeochemistry. NanoSIMS analyses of a Jurassic glendonite from Siberia produced large C-isotope gradients (> 40‰) over micrometer distances hinting at strong kinetic fractionation that is coupled to the formation of various precipitates, including an inclusion-rich primordial phase with C-isotope values as low as -38‰ that records methane oxidation. In line with previous results from Siberia, all investigated glendonites from the Cretaceous of Svalbard contain methane gas (700 - 2500 ppb/g) with enriched δ13C-CH4 signatures (-44 to -50‰ V-PDB), depleted δ2H--CH4 (-285 to -245‰ V-SMOW), and relatively large proportions of C2-C5 gas. Such values are potentially indicative of thermogenic methane gas sourced from structure II gas hydrates. Organic geochemistry of glendonites from Svalbard shows the presence of abundant hopanes, including bisnorhopanes with a CSIA signature of -41‰, suggesting activity of sulfide oxidizing bacteria possibly also linked to the inclusion of oil droplets. Moreover, exceptionally heavy bulk δ34Scas values of +46.2‰ clearly link marine ikaite formation in deep time to sulfate-driven anaerobic methane oxidation. Marine ikaite formation and preservation is thus a highly complex process, driven by temperature and (bio)chemical processes in the sea floor, complicating its use as a simple paleoclimate proxy. Regardless, glendonite episodically trapped large amounts of greenhouse gases and stored those for hundreds of millions of years, making this authigenic mineral a potential recorder of past carbon cycle perturbations.

How to cite: van de Schootbrugge, B., Schobben, M., Morales, C., Polerecky, L., Kienhuis, M., Nierop, K., Peterse, F., Janssen, N., He, T., Newton, R., van Winden, J., Weijers, J., Podlaha, O., Sluijs, A., and Middelburg, J.: Mineral-trapping of greenhouse gases in Arctic glendonites, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13182,, 2023.