Current Research on Seabed Hazards of the Baffin Continental Shelf and Slope, Eastern Canadian Arctic

Robbie Bennett

Hydrocarbon resource potential of the Baffin Bay region is similar to or greater than the Beaufort-Mackenzie basin. Although there are no current exploration plans for the Canadian portion of Baffin Bay, elevated interest to open the area in the future is expected. Before determining if exploration can proceed, scientific understanding of geological hazards is essential. The Geological Survey of CA has initiated a study of marine geological hazards (geohazards) in Baffin Bay with the goals of providing a predictive framework for the geological and engineering properties of the seabed, and determining the regional distribution and severity of seabed hazards. Geohazards in the Baffin region differ from elsewhere on CA's eastern continental margin. It is a seismically active passive margin; one of the largest passive margin earthquakes ever recorded occurred in Baffin Bay in 1933 with a magnitude of 7.3. Its Arctic location means the area is more prone to the effects of iceberg scour and sea ice. The modern seafloor morphology and shallow stratigraphy are strongly influenced by past glacial processes. The Baffin Shelf consists of glacially eroded transverse troughs separated by flat-topped banks. Glacial ice-contact and ice-proximal sediments rest on bedrock and are overlain discontinuously by variable thicknesses of postglacial sand or mud. Geohazards on the Baffin Shelf include ice scour, hydrocarbon venting features, and uneven glacially-modified seabed. In northern Baffin Bay, ice scouring destroyed seabed monitoring equipment in 427 m of water in 1967-1968. Glacial flutes on the seafloor within transverse troughs are up to 75 m high and have gradients up to 60° along their flanks. Hydrocarbon seeps occur along the northern Baffin Shelf and sea-surface hydrocarbon slicks have been observed from 1976 to present. Deepwater geohazards in Baffin Bay are mainly related to seabed instability. Sparse high-resolution seismic data near the 1933 epicentre show no evidence for slope failure, but widespread sediment failure deposits are observed elsewhere along the lower Baffin Slope. Studies from the late 1980’s identified a large bank-edge failure zone, possibly related to deeply penetrating faults. Re-assessment of legacy data shows extensive erosion of the slope down to 1500 m water depth, but it is unclear if the erosion is related to sediment failure or erosion by vigorous bottom currents. The eroded zone on the slope extends more than 800 km from off Home Bay in the south to off Scott Inlet in the north. Geological data coverage in Baffin Bay is not complete and much of the legacy data are of limited quality and not suitable for geohazard assessment. The Baffin Slope and deep water areas are especially lacking in suitable data coverage. Modern multibeam bathymetry, high-resolution seismic, and sediment samples focused specifically on developing a regional understanding of geohazards in Baffin Bay are required to advance this work.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013