EGU2020-21868
https://doi.org/10.5194/egusphere-egu2020-21868
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Methane hydrate mobilization by ice stream erosion during the last glacial

Pavel Serov1, Henry Patton1, Malin Waage1, Calvin Shackleton1, Jurgen Mienert1, Karin Andreassen1, and Alun Hubbard1,2
Pavel Serov et al.
  • 1UiT - The Arctic University of Norway, CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Tromsø, Norway (pavel.russerov@uit.no)
  • 2Aberystwyth University, Aberystwyth, United Kingdom

During the past ~2.6 Ma, some 30 glaciations have caused episodic high pressure and low temperature conditions and forced growth and decay of extensive subglacial methane hydrate accumulations globally. Research on Arctic methane release has primarily focused on warm, interglacial episodes when hydrates became unstable across territories either abandoned by former ice sheets or affected by permafrost degradation. Here we present a new mechanism – the subglacial erosion of gas hydrate-bearing sediments – that actively mobilizes methane in hydrate and dissolved form and delivers it to the ice sheet margin. We investigate this mechanism using geophysical imaging and ice sheet/gas hydrate modeling focused on a study site in Storfjordrenna, that hosted large ice stream draining the Barents Sea ice sheet. During the last glacial, we find that this ice stream overrode an extensive cluster of conduits that supplied a continuous methane flux from a deep, thermogenic source and delivered it to the subglacial environment. Our analysis reveals that 15,000 to 44,000 m3 of gas hydrates were subglacially eroded from the 17 km2 study site and transported to the shelf-edge. Given the abundance of natural gas reservoirs across the Barents Sea and marine-based glaciated petroleum provinces elsewhere, we propose that this mechanism had the potential to mobilize a substantial flux of subglacial methane throughout multiple Quaternary glacial episodes.

How to cite: Serov, P., Patton, H., Waage, M., Shackleton, C., Mienert, J., Andreassen, K., and Hubbard, A.: Methane hydrate mobilization by ice stream erosion during the last glacial, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21868, https://doi.org/10.5194/egusphere-egu2020-21868, 2020