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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L01603, doi:10.1029/2006GL027977, 2007

Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates

Charles K. Paull

Monterey Bay Aquarium Research Institute, Moss Landing, California, USA


William Ussler III

Monterey Bay Aquarium Research Institute, Moss Landing, California, USA


Scott R. Dallimore

Natural Resources Canada, Sidney, British Columbia, Canada


Steve M. Blasco

Natural Resources Canada, Dartmouth, Nova Scotia, Canada


Thomas D. Lorenson

U.S. Geological Survey, Menlo Park, California, USA


Humfrey Melling

Fisheries and Oceans Canada, Sidney, British Columbia, Canada


Barbara E. Medioli

Natural Resources Canada, Ottawa, Ontario, Canada


F. Mark Nixon

Natural Resources Canada, Ottawa, Ontario, Canada


Fiona A. McLaughlin

Fisheries and Oceans Canada, Sidney, British Columbia, Canada


Abstract

The Arctic shelf is currently undergoing dramatic thermal changes caused by the continued warming associated with Holocene sea level rise. During this transgression, comparatively warm waters have flooded over cold permafrost areas of the Arctic Shelf. A thermal pulse of more than 10°C is still propagating down into the submerged sediment and may be decomposing gas hydrate as well as permafrost. A search for gas venting on the Arctic seafloor focused on pingo-like-features (PLFs) on the Beaufort Sea Shelf because they may be a direct consequence of gas hydrate decomposition at depth. Vibracores collected from eight PLFs had systematically elevated methane concentrations. ROV observations revealed streams of methane-rich gas bubbles coming from the crests of PLFs. We offer a scenario of how PLFs may be growing offshore as a result of gas pressure associated with gas hydrate decomposition.

Received 23 August 2006; accepted 20 November 2006; published 5 January 2007.

Keywords: Arctic; methane gas hydrate; gas venting.

Index Terms: 0702 Cryosphere: Permafrost (0475); 1630 Global Change: Impacts of global change (1225); 3002 Marine Geology and Geophysics: Continental shelf and slope processes (4219); 3004 Marine Geology and Geophysics: Gas and hydrate systems; 9315 Geographic Location: Arctic region (0718, 4207).

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Citation: Paull, C. K., W. Ussler III, S. R. Dallimore, S. M. Blasco, T. D. Lorenson, H. Melling, B. E. Medioli, F. M. Nixon, and F. A. McLaughlin (2007), Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates, Geophys. Res. Lett., 34, L01603, doi:10.1029/2006GL027977.