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Nat Commun. 2016 May 11;7:11509. doi: 10.1038/ncomms11509.

Timescales of methane seepage on the Norwegian margin following collapse of the Scandinavian Ice Sheet.

Author information

1
Marine Geology, Geological Survey of Norway, Postal box 6315 Sluppen, 7491 Trondheim, Norway.
2
CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT the Arctic University of Norway, 9037 Tromsø, Norway.
3
Institute of Geology, Tallinn University of Technology, 19086 Tallinn, Estonia.
4
Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia.
5
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK.
6
Lundin Norway AS, 1366 Lysaker, Norway.

Abstract

Gas hydrates stored on continental shelves are susceptible to dissociation triggered by environmental changes. Knowledge of the timescales of gas hydrate dissociation and subsequent methane release are critical in understanding the impact of marine gas hydrates on the ocean-atmosphere system. Here we report a methane efflux chronology from five sites, at depths of 220-400 m, in the southwest Barents and Norwegian seas where grounded ice sheets led to thickening of the gas hydrate stability zone during the last glaciation. The onset of methane release was coincident with deglaciation-induced pressure release and thinning of the hydrate stability zone. Methane efflux continued for 7-10 kyr, tracking hydrate stability changes controlled by relative sea-level rise, bottom water warming and fluid pathway evolution in response to changing stress fields. The protracted nature of seafloor methane emissions probably attenuated the impact of hydrate dissociation on the climate system.

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