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A Synthesis of the Scott Inlet Oil Seep, Baffin Bay, Canada

Phil N. Moir1, Gordon N. Oakey1, Robbie Bennett1, Kate Dickie1, Paul Budkewitsch3, Mark Obermajer2, and Martin Fowler4
1Geological Survey of Canada Atlantic, Dartmouth, NS, Canada.
2Geological Survey of Canada Calgary, Calgary, NS, Canada.
3Canada Centre for Remote Sensing, Ottawa, ON, Canada.
4Talisman Energy, Calgary, AB, Canada.

Oil slicks were first recorded on the sea surface offshore Scott Inlet, Baffin Island, in 1976 by a scientific team from Bedford Institute of Oceanography. In following years, several expeditions successfully collected various geophysical and chemical data, sediment, bedrock and water samples. This included using the Pisces IV submersible in 1981 and 1985 to visually examine the seafloor and collect targeted samples. This early work confirmed that oil and gas were indeed seeping from several locations. Video footage showed areas with distinctive white Beggiatoa bacteria-encrusted sediments, locally solidified into a carbonate crust which was trapping oil beneath it. In addition, extensive surface slicks were mapped and observed in several locations off Scott Inlet and Buchan Gulf. While many elements of this active petroleum system remain unknown, a synthesis of recent work provides further insight.
Repeat sea surface mapping using satellite radar confirms the continued existence of extensive and persistent oil slicks. As well, a succession of multibeam seismic surveys over the area have illuminated details of the seafloor Quaternary geology, petroleum escape features, and the surface expression of the underlying bedrock.
Analysis of samples and bedrock mapping provide an interpretation of Precambrian basement overlain by Cretaceous and Cenozoic strata. Upper Cretaceous mudstones and shales cored at several locations were originally dated as Campanian in age; recent palynological work provides a more precise Turonian to Campanian age for the mudstones of Home Bay and Buchan Gulf, and the black shales cored at Scott Inlet. These are equivalent to strata on Bylot Island, approximately 300 km NW of Scott Inlet, as well as possible marine Cenomanian-Turonian source rocks identified on Ellesmere Island and West Greenland.

New analysis of oil collected from the 1986 submersible experiment confirms a biodegraded mature oil with biomarkers suggesting an Upper Cretaceous marine source, possibly similar to oils indentified in West Greenland.

Regional mapping using 2D seismic reflection and refraction profiles reveals an elongate (200-300 km by 25-50 km wide), NW-SE-striking graben, named Scott Inlet Basin. It contains up to 6 km of sedimentary strata thought to correlate with Cretaceous and Cenozoic strata on Bylot Island.

Recent geological mapping on Bylot Island (see Haggart et al., this meeting) may provide clues to the stratigraphy of Scott Inlet Basin. Oldest strata there are middle Albian to possible Turonian coarse sands, suggesting correlation with the Hassel Formation of the western Canada Arctic. Younger strata contain floral assemblages of Coniacian, Santonian, early late Maastrichtian, late early or early late Paleocene, and late Paleocene ages. A thick (500m), coarse-grained sandstone widespread on SW Bylot Island grades laterally into deep marine mudstone and may be a possible coeval equivalent for a Scott Inlet Basin reservoir rock.

 

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.

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