F.A. Stoakes, 1992. "Woodbend Megasequence", Devonian-Early Mississippian Carbonates of the Western Canada Sedimentary Basin: A Sequence Stratigraphic Framework, Jack Wendte, Frank A. Stoakes, Clarence V. Campbell
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This sequence comprises the strata between the Beaverhill Lake Group (Chapter 7) and the Winterburn Group (Chapter 9). The stratigraphic section includes shallow-water carbonates of the Cooking Lake, Leduc and Grosmont formations and deep-water carbonates and shales of the Majeau Lake Member, Duvernay and Ireton formations. The isolate reef complexes of the Leduc Formation are especially well known because they contain some of the largest oil reserves in the WCSB. In central Alberta, the basin-fill succession of the Woodbend Group differs markedly from that of the underlying Beaverhill Lake Group. Rather than being comprised dominantly of carbonate muds derived from coeval carbonate banks to the east, Woodbend basin-fill units have a significant clay shale content. The occurrence of these shales marks the initial delivery of terrigenous deposits into the central Alberta Basin from an extrabasinal northerly source. The configuration of these shale "banks" controls the distribution of some overlying carbonate platform deposits.
Figure 1 depicts the configuration of the Alberta Basin during the Woodbend which marks the furthest incursion of the open-marine Devonian seaway onto the craton. Shallow-water platform carbonates occur along the periphery of this basin in east-central Alberta, in the Devonian "Deep Basin" area of west-central Alberta and around the Peace River Arch landmass.
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Devonian-Early Mississippian Carbonates of the Western Canada Sedimentary Basin: A Sequence Stratigraphic Framework
The Devonian and early Mississippian strata in the Western Canada Sedimentary Basin include a wide diversity of shallow-water carbonate and basin filling carbonate, shale and evaporite facies. Of these, the large Devonian platform-reef complexes are the most spectacular. They occur in magnificent exposures in the Front Ranges of the Canadian Rockies and in the subsurface of Alberta. In the subsurface, these complexes pool many of the largest oil and gas accumulations in Western Canada. This short course is intended to provide a summary of Devonian and early Mississippian deposits in the subsurface of the Western Canada Sedimentary Basin. One of the major goals is to present the evolution of these strata in a sequence-stratigraphic context. The role of sea-level, tectonic and depositional controls on “stacking” and facies patterns are considered. A second major goal is to relate the occurrence of hydrocarbon pools to this sequence-stratigraphic framework.