|Titre||Deep water seabed geohazard investigations in the Beaufort Sea related to offshore hydrocarbon development|
|Auteur||Blasco, S; Bennett, R; MacKillop, K; Campbell, P; Carr, E; Hughes-Clarke, J|
|Source||39th Annual Yellowknife Geoscience Forum, abstracts of talks and posters; par Fischer, B J; Watson, D M; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume vol. 2011,
2011 p. 22 (Accès ouvert)|
|Liens||Online - En ligne |
|Séries alt.||Secteur des sciences de la Terre, Contribution externe 20110320|
|Réunion||39th Annual Yellowknife Geoscience Forum; Yellowknife, NWT; CA; Novembre 15 - 17, 2011|
|Document||publication en série|
|Province||Région extracotière du nord|
|Sujets||hydrocarbures; capacité de production d'hydrocarbures; milieux marins; géologie marine; combustibles fossiles|
|Programme||Géoscience marine pour le développement économique de l'Arctique, Géoscience en mer|
|Résumé||(disponible en anglais seulement)|
Seabed mapping in support of a regional assessment of geohazards affecting deep water hydrocarbon development in the Beaufort Sea continued in 2011. The
collaborative study among the GSC, ArcticNet, IOL, and BP began in 2009. This year, mapping technologies included multibeam sonar and a high resolution subbottom profiler used onboard the Coast Guard icebreaker Amundsen. The seabed, to depths of 100
m below seafloor, was investigated in water depths of 50 to 1300 m.
Research results to date indicate a variety of seabed stability conditions exist along the outer shelf ands upper slope region of the Beaufort Sea. The regional geohazard
framework is largely controlled by processes associated with multiple glaciations: emergence of the shelf during sea level lowstands; permafrost aggradation; rapid deposition of glacial outwash; failure of outwash deposits down slope; and submergence
of the shelf following the retreat of the ice sheet. Ice scouring observed to water depths of 150 m may be relict and related to historically more severe sea-ice regimes or to scouring during lower sea levels. Subsea ice-bearing permafrost may
terminate in 100 m water depths as it was generated when the shelf was subaerially exposed. Sea level was 100 m or more below present during periods of glaciation. The shelf edge at 100 m is associated with concentrations of mud volcanoes and
pockmarks. Gas venting in association with these features may result from gas migration from beneath the impermeable permafrost to the edge of permafrost at shelf edge. Low-strength sediments that thicken down slope from the shelf edge may result
from rapid deposition rates of distal glacial outwash. Submarine slides that occur at the shelf edge and down slope may be retrogressive in nature. Faulting in near surface sediments may relate to shelf edge insatiability processes. Gas hydrate has
been observed in one sediment core down slope. Ongoing research will focus on continued mapping of the spatial distribution and temporal activity of geohazards. Relict instability features may not be relevant to offshore hydrocarbon development.
Research results have been incorporated into the current 'Arctic Review' by the National Energy Board.