Geology and Evolution of Baffin Bay: Petroleum Potential of the Eastern Canadian Arctic Margin
Gordon N. Oakey1, Tom Brent2, Chris Harrison2, Hans Wielens1, and Chris Jauer2
1Geological Survey of Canada (Atlantic), Dartmouth, NS, Canada.
2Geological Survey of Canada (Calgary), Calgary, AB, Canada.
The Baffin Island continental margin is broadly subdivided into three potentially economic areas: 1) the Saglek Basin; 2) the Baffin Shelf; and 3) the Lancaster Basin. Both the Saglek and Lancaster basins developed at the mouths of continental-scale drainage systems where prograding deltaic successions exceed 8 km in thickness.
Within the Saglek Basin, exploration wells drilled in the 1970s and early 1980s resulted in one significant discovery at the Hekja O-71 site, seaward of Frobisher Bay. This gas field likely contains more than 60 BCM natural gas in the Upper Paleocene Gudrid Sands of the Cartwright Formation. At the base of all three northern wells were thick Paleocene basalts. Upper Cretaceous Markland shales were identified in all the southern wells as well as the Gjoa G-37 well and may represent the primary source rock within the basin. 4D petroleum systems modelling indicates several new large prospective target areas.
The Baffin Shelf is relatively narrow (~100 km) with numerous small pull-apart basins. The sediment thickness within these isolated basins rarely exceeds 6 km. The presence of an petroleum system is demonstrated by an active oil seep at Scott Inlet, with organic geochemistry indicating a biodegraded mature oil from an Upper Cretaceous source rock.
The ODP-645 well bottomed in Lower Miocene strata, and provides the only direct tie to regional industry seismic data. A 650 km long seismic transect has been assembled to provide a preliminary correlation of the ODP seismic units along the northern Baffin margin to the mouth of Lancaster Sound.
In the northern Baffin Bay region, Mesozoic and Cenozoic successions are distributed in several sub-basins structurally bounded by major NW-oriented basement structures. The Lancaster Basin is a northward dipping half graben, with over 8 km of Mesozoic and Cenozoic strata overlying high-velocity Paleozoic and/or Proterozoic strata. Gravity modelling indicates that significant crustal thinning occurred beneath the basin. Minimal structural deformation is observed in the southern areas while complex thrust faulting and inversion structures increase to the north. The Late Cretaceous and Paleocene shales and sandstones are exposed within the Eclipse Trough, onshore Bylot Island. The shales are thermally immature but have promising TOC values. These sequences likely extend into the Lancaster Basin, where deeper burial and higher heat flow would be favourable for petroleum generation.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia