Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden

• DOI: 10.1038/s41467-019-12728-y
• Publication Date: 2019-10-18T12:05:56Z
• Authors: Henrik Drake; Nick M. W. Roberts; Christine Heim; Martin J. Whitehouse; Sandra Siljeström; Ellen Kooijman; Curt Broman; Magnus Ivarsson; Mats E. Åström
• Keywords: Impact structure; Devonian

Abstract Fractured rocks of impact craters may be suitable hosts for deep microbial communities on Earth and potentially other terrestrial planets, yet direct evidence remains elusive. Here, we present a study the largest crater Europe, Devonian Siljan structure, showing that structures can important unexplored long-term activity. Secondary carbonate minerals dated to 80 ± 5 22 3 million years, thus postdating by more than 300 have isotopic signatures revealing both methanogenesis anaerobic oxidation methane in bedrock. Hydrocarbons mobilized from matured shale source were utilized subsurface microorganisms, leading accumulation mixed with thermogenic possibly minor abiotic gas fraction beneath sedimentary cap rock at rim. These new insights into hosted activity implications understanding astrobiological consequences impacts.