An Introduction to Baffin Fan and Its Inverted Rift System, Arctic Eastern Canada

Christopher Harrison¹, Thomas A. Brent², and Gordon N. Oakey^3
1Geological Survey of Canada, Ottawa, ON, Canada.
²Geological Survey of Canada, Calgary, AB, Canada.
³Geological Survey of Canada, Dartmouth, NS, Canada.

This paper provides a geological overview and introduction to hydrocarbon potential of the Cenozoic Baffin Fan of western Baffin Bay and of the underlying rift system.
Syn-rift Upper Cretaceous to Danian strata are correlated with exposures in West Greenland, Bylot Island and the Canadian Arctic Islands. The existence of Cretaceous oil source rocks at depth is indicated by the organic geochemical signature of hydrocarbons from the Scott Inlet seep (MacLean et al. 1981; Fowler, pers. comm., 2008).

Seismic Selandian strata, deposited during an early phase of sea floor spreading in Baffin Bay, are correlated with the lower Eureka Sound Group of Ellesmere Island. These reach 3000 m in some grabens. The next three sequences span the Thanetian to Eocene interval and were deposited during predominantly northward motions of Greenland, and the related second phase of sea floor spreading in Baffin Bay. Age range and facies are based on features present in the upper Eureka Sound Group and include fluvial-deltaic sandstones, coal, and conglomerate. These sequences were deposited during phases of compressive deformation and growth of anticlines and inversion structures observed on horst block highs.

Baffin Fan is an Eocene to upper Pleistocene sediment wedge up to 12 km thick that occupies an area comparable to that of the entire Beaufort-Mackenzie Basin. Peak accumulation rates are associated with an Oligocene to upper Miocene seismic sequence that ranges to 5700 m thick. Miocene and older shelf-deltaic facies are preserved under a Plio-Pleistocene submarine canyon complex and under correlative Plio-Pleistocene submarine fan deposits north of Bylot Island.

The petroleum geology of Baffin Fan and its inverted rift system, although based on indirect evidence, compares favourably to the Beaufort-Mackenzie Basin. While rift and drift phases are younger for Baffin Fan, there is strong indication of pre-migration structure development. With some certainty, it can be predicted that gas prone source rocks and suitable reservoirs are thick and widespread in various Cretaceous through Eocene formations. Cenomanian-Turonian oil source rocks are likely preserved in the major half grabens and it is probable that Eocene oil source rocks are present throughout deeper buried parts of the fan.

From a depth to basement map, forty (40) untested structural targets are identified in western Baffin Fan and in its rift system. These are located in a belt of prospects that runs 220 km northwestward from east of Bylot Island to east of Coburg Island. Sixty-five percent (i.e. 28 of the 40) are located under Neogene cover of Baffin Fan. There are 14 structures that each enclose an area in excess of 70 km²; five range between 334 and 592 km². Based on success rates from drilling in the Beaufort-Mackenzie Basin it can be expected than approximately 29%, or 12 of the 40 mapped structures, might contain hydrocarbons in significant quantity.

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