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Article Dans Une Revue Geology Année : 2017

Glendonites track methane seepage in Mesozoic polar seas

Chloe Morales
  • Fonction : Auteur
Mikhail Rogov
  • Fonction : Auteur
Hubert Wierzbowski
  • Fonction : Auteur
Victoria Ershova
  • Fonction : Auteur
Thierry Adatte
Karl B. Foellmi
  • Fonction : Auteur
Erik Tegelaar
  • Fonction : Auteur
Gert-Jan Reichart
  • Fonction : Auteur
Gert J. De Lange
  • Fonction : Auteur
Jack J. Middelburg
  • Fonction : Auteur
Bas van De Schootbrugge
  • Fonction : Auteur

Résumé

During the Phanerozoic, Earth has experienced a number of transient global warming events associated with major carbon cycle perturbations. Paradoxically, many of these extreme greenhouse episodes are preceded or followed by cold climate, perhaps even glacial conditions, as inferred from the occurrence of glendonites in high latitudes. Glendonites are pseudomorphs of ikaite (CaCO3 center dot 6H(2)O), a hydrated carbonate mineral increasingly stable at low temperatures. Here, we show that methane seepage and oxidation provide an overriding control on Mesozoic glendonite formation (i. e., ikaite fossilization). Geochemical and petrological analyses of 33 Early Jurassic to Early Cretaceous glendonites from five sections in Siberia (Russia) reveal that most of their infilling carbonate phases are reminiscent of methane- derived authigenic carbonates. Bulk glendonites and surrounding sediments exhibit exceptionally high and low carbon isotope values (+20% to -45% VPDB [Vienna Peedee belemnite]), typical for carbon sources linked to methane generation and oxidation. Gas inclusion data confirm the presence of methane and longer-chain hydrocarbon gases, suggesting a thermogenic source for the methane. Glendonitebearing layers can be traced for hundreds of kilometers, suggesting widespread trapping of methane in the sub-seafloor during the Jurassic. As such, glendonites constitute an unexplored archive for detecting past episodes of methane release and oxidation in polar settings.
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Dates et versions

hal-02329286 , version 1 (23-10-2019)

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Chloe Morales, Mikhail Rogov, Hubert Wierzbowski, Victoria Ershova, Guillaume Suan, et al.. Glendonites track methane seepage in Mesozoic polar seas. Geology, 2017, 45 (6), pp.503-506. ⟨10.1130/G38967.1⟩. ⟨hal-02329286⟩
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