https://doi.org/10.5194/tc-2021-226 Preprint. Discussion started: 9 August 2021 c Author(s) 2021. CC BY 4.0 License. 1 Review Article: Permafrost Trapped Natural Gas in 2 Svalbard, Norway 3 Authors: Thomas Birchall*1, 2, Malte Jochmann1, 3, Peter Betlem1, 2, Kim Senger1, Andrew 4 Hodson1, Snorre Olaussen1 5 1Department of Arctic Geology, The University Centre in Svalbard, P.O. Box 156, N-9171 Longyearbyen, 6 Svalbard, Norway 7 2Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway 8 3Store Norske Spitsbergen Kulkompani AS, Vei 610 2, 9170 Longyearbyen, Svalbard. Norway 9 *Correspondence to: Thomas Birchall (
[email protected]) 10 11 Abstract. Permafrost has become an increasingly important subject in the High Arctic archipelago of Svalbard. 12 However, whilst the uppermost permafrost intervals have been well studied, the processes at its base and the 13 impacts of the underlying geology have been largely overlooked. More than a century of coal, hydrocarbon and 14 scientific drilling through the permafrost interval shows that accumulations of natural gas trapped at the base 15 permafrost is common. They exist throughout Svalbard in several stratigraphic intervals and show both 16 thermogenic and biogenic origins. These accumulations combined with the relatively young permafrost age 17 indicate gas migration, driven by isostatic rebound, is presently ongoing throughout Svalbard. The accumulation 18 sizes are uncertain, but one case demonstrably produced several million cubic metres of gas over eight years. Gas 19 encountered in two boreholes on the island of Hopen appears to be situated in the gas hydrate stability zone and 20 thusly extremely voluminous.