View Paper

GEOHAZARD INVESTIGATIONS OF PERMAFROST AND GAS HYDRATES IN THE OUTER SHELF AND UPPER SLOPE OF THE CANADIAN BEAUFORT SEA

Session: John Ross MacKay Symposium - Permafrost II / Symposium John Ross MacKay - Pergélisol II

Scott Dallimore, Geological Survey of Canada (Canada)
C.K. Paull, Monterey Bay Aquarium Research Institute (United States)
A.E. Taylor, Geological Survey of Canada (Retired) (Canada)
M. Riedel, Geological Survey of Canada (Canada)
H.A. MacAulay, Geological Survey of Canada (Canada)
M.M. Côté, Geological Survey of Canada (Canada)
Y.K. Jin, Korean Polar Research Institute (South Korea)

Building on the early work of J. Ross Mackay, this paper reviews the state of knowledge of offshore permafrost and gas hydrates beneath the Beaufort Shelf. A thick and extensive interval of transgressed terrestrial permafrost is present beneath the central shelf, warming seaward and pinching out at 90-100m water depth near the shelf-slope break. A complex gas hydrate regime is recognised with possible intrapermafrost and subpermafrost gas hydrate beneath the shelf, a zone with no gas hydrates at the shelf-slope transition, and a marine gas hydrate zone where water depths are greater than ~270 m. We believe that changes induced by transgression (formation and thawing of ground ice and gas hydrate) have created unique porous media conditions in this setting that can influence geohazards and active geologic processes. To this end we have undertaken a variety of multidisciplinary field investigations that have included marine geophysics, high resolution sea bed mapping, sediment coring, sea floor moorings and ROV dives.