Index and regional paleogeography map, identifying six paleogeographic areas, the location of the master and discretionary cross sections and the reference wells.
Table of formations for each of the six defined paleogeographic areas, presented in a northwest to southeast orientation. The biostratigraphic zonation of Braun et al. (1988) is illustrated.
Beaverhill Lake isopach map. The isopach interval does not include the Watt Mountain Formation because of database limitations; however, the Watt Mountain is less than 20 m thick and does not significantly affect this map. Neither does it include the Dawson Bay Formation, which is mapped separately (Fig. 11.14). The Beaverhill Lake Group attains a maximum thickness of 240 m in east-central and northeastern Alberta, within the Waterways Basin, an intra-platform basin. The strata thin eastward as a result of erosion. The group also thins westward as it onlaps the emergent Peace River Arch and West Alberta Ridge. The bank margin of the transgressive sequence is outlined. A depositional thickening, the Hotchkiss Embayment, separates the Peace River Arch Fringing Reef Complex from the Hay River Bank. Isopach thickening within the basinal area west of the Hay River Bank margin, and within the Cordova Embayment, occurs as a result of an inability to differentiate between Beaverhill Lake and older basinal strata. Hydrocarbon accumulations occur along the bank margins and within the bank complexes.
Transgressive phase isopach map. The transgressive phase exhibits general southeastward thinning from the bank margin of the Hay River Bank. Shallow-marine carbonates onlapped the emergent Peace River Arch. In the Swan Hills Complex the bank developed aggradationally and thickened to over 100 m. In southern Saskatchewan the transgressive phase thins to less than 20 m and forms the lower portion of the Souris River Formation (not shown). The Dawson Bay Formation and its equivalent, the Watt Mountain Formation, are not included because of database limitations in differentiating the Watt Mountain Formation (see also Figure 11.14).
Regressive phase isopach map. The regressive phase attains a thickness of more than 200 m in east-central and northeastern Alberta, representing the depocentre of the Waterways Basin. Depositionally it thins northward and westward as it downlaps the bank complexes of the transgressive phase and the Peace River Arch. Southward and eastward, the sequence thins as basinal clinothems grade laterally to the shelf carbonates and evaporites that make up the Souris River Shelf in the southern part of the basin.
Subsurface reference wells. Vertical scale is Atlas standard 1:3000.
a. B.A. Shell Klua b-49-F;94-J-9 is the reference well for the Hay River Bank area. It is a tie well
for master cross sections A-A* (Fig. 11.8a) and B-B' (Fig. 11.9) and is included in Figure 11.18.
b. The Peace River Arch Fringing Reef Complex is represented by the Chevron Supst. Dome Loon 4-17-85-9W5M
well. The Slave Point and Fort Vermilion formations were cored and described in detail by Craig (1987).
The Firebag Member of the Waterways Formation is absent through non-deposition, as a result of onlap.
c. The Home Regent "A" Swan Hills 10-10-67-10W5M well is the subsurface type section for the Swan
Hills Formation (Leavitt and Fischbuch, 1968). The section is modified to reflect the regional stratigraphy
of the Swan Hills Complex.
d. Craig (1987) proposed the Imperial Bailey Selburn Riverdale 1-27-60-26W4M well as the subsurface type
section for the Waterways Formation. The well occurs within and is representative of the stratigraphy of
the Waterways Basin.
e. The Socony Sohio Hatfield 11-14-28-22W2M well represents the stratigraphy of the Souris River Shelf.
Lane (1964) proposed this well as the subsurface type section for the Souris River Formation. Dunn's
(1982a) member subdivision for the Dawson Bay Formation is illustrated.
Regional structure map on the top surface of the Beaverhill Lake and Manitoba groups. Within Alberta, the surface has a monoclinal dip that increases in a westerly direction. The Horn River Basin in northeast British Columbia is depicted by a structural low. A structural ridge is evident in southeastern Alberta, reflecting post-Devonian tectonics associated with the Sweetgrass Arch. Post-Devonian tectonics are also reflected in southeastern Saskatchewan by the development of the Williston Basin during the late Paleozoic. Local anomalies reflect differential bevelling of the Beaverhill Lake Group along the subcrop edge, and post-Frasnian salt dissolution in southern Saskatchewan.
Master cross section A-A' (northern portion), illustrating the stratigraphic relationship between the Waterways Basin, Swan Hills Complex, Peace River Arch Fringing Reef Complex, Hay River Bank and Horn River Basin. The transgressive sequence thickens and forms the Swan Hills Complex, south of the arch. This complex is separated from the Peace River Arch Fringing Reef Complex, as illustrated, by a depositional thinning of the Slave Point Formation. The fringing reef complex depositionally onlaps the Peace River Arch paleo-landmass. Along the north side of the arch the reef complex is separated from the Hay River Bank by the Hotchkiss Embayment. The transgressive sequence (Slave Point Fm) thickens northward to the margin of the Hay River Bank. The Waterways Formation thickens within the Hotchkiss and Klua embayments, reciprocating the thinning of the Slave Point Formation. The Evie Reef, a Horn River Basin reef complex, is illustrated by b-85-H; 94-J-14. The Horn River Basin consists of undifferentiated Givetian and Frasnian basinal sediments.
Cross section A-A' (southern portion), illustrating the relation between the dominant basinal strata of the regressive phase (Waterways Basin) and the shallow-marine carbonates and evaporites of the Souris River Shelf. The basin-slope strata (clinothem phase) of the Waterways Formation can be correlated with the shallow-marine strata (fondothem phase) of the Souris River Formation. The facies change is illustrated diagrammatically as abrupt, but in detail the shelf carbonates prograde basinward into the Waterways Basin. Each successive clinothem cycle is generally thinner and is dominated by a greater proportion of carbonate (versus shale), suggesting infilling of the basin through time. The Mildred Member represents the lower portion of a clinothem cycle. The upper part is represented by at least some of the Cooking Lake Formation in Alberta or the lower portion of the Duperow Formation in Saskatchewan. The Slave Point Formation (platform facies) thins in a southeasterly direction and becomes indistinguishable within the Souris River Formation. The Watt Mountain Formation thins and becomes equivalent to the Dawson Bay Formation in southern Saskatchewan (Souris River Shelf).
Cross section B-B', illustrating a southwest-northeast transect from Clarke Lake in northeastern British Columbia, across the Hay River Bank to Deep Bay in the southern Northwest Territories. The Hay River Bank margin (well C-04) formed proximal to the Tathlina High, a Middle Devonian paleotopographic high. The Elk Point succession thins stratigraphically in a northeasterly direction. The Deep Bay Bank (well B-01) developed within the Horn River Basin. Within the Cordova Embayment (d-20-I; 94-P-10), shelf carbonates of the Elk Point and Beaverhill Lake groups grade abruptly to basinal strata of the Horn River Formation. The regressive phase Waterways Formation depositionally onlaps (downlaps) the bank complex along the bank margin.
Cross section C*-C', along the axis of the Peace River Arch. The underlying Elk Point Group depositionally onlaps the arch in a westerly direction. The Beaverhill Lake transgressive reefal sequence thickens and develops a bank complex marginal to the arch. The regressive phase onlaps (downlaps) the bank complex.
Cross section D-D', illustrating the stratigraphic relations between the Souris River Shelf, Waterways Basin and Swan Hills Complex in an east-west direction. The basin-fill regressive phase dominates most of the section. Clinothem sequences can be correlated regionally. These basinal to slope cycles grade laterally into shallowing-upward carbonate-evaporite cycles of the Souris River Shelf. Westward the clinothems depositionally downlap the Swan Hills Complex.
Cross section F-F", depicting the Souris River Shelf in southeastern Alberta and southwestern Saskatchewan. It is composed of several shallowing-upward carbonate-evaporite sequences. The Dawson Bay Formation thins as it depositionally onlaps the Sweetgrass Arch, a pre-Devonian paleotopographic high.
Cross section G-G', illustrating Manitoba Group stratigraphy in southeastern Saskatchewan and southwestern Manitoba. The Second Red Bed Member of the Dawson Bay Formation unconformably overlies evaporites of the Elk Point Group and represents a unit transitional to the overlying carbonates of the Dawson Bay Formation. The Dawson Bay Formation forms a deepening-upward transgressive sequence. The First Red Bed Member of the Souris River Formation disconformably to unconformably overlies the Dawson Bay Formation and is transitional with the carbonates of the Souris River Formation (regressive phase). The Souris River Shelf is composed of several, regionally correlatable, shallowing-upward carbonate-evaporite cycles.
Dawson Bay and Watt Mountain isopach map. The Dawson Bay Formation thickens to over 60 m in the Dawson Bay Basin in parts of southern Saskatchewan. It is stratigraphically equivalent to the Watt Mountain Formation in Alberta, which is generally less than 20 m thick, except in the vicinity of the Peace River Arch (PRA), where the Gilwood Member constitutes a fluvial-deltaic sequence. Its thickness varies from approximately 20 m in the Mitsue area (south of the PRA) to up to 70 m along the north flank of the PRA (Rottenfusser and Oliver, 1977). Its distribution cannot be mapped regionally due to limitations of the database, however it has been mapped south of the PRA by Jansa and Fischbuch (1974) and north of the PRA by Rottenfusser and Oliver (1977). The Watt Mountain Formation thins northward from the PRA, coincident with the thinning of the Gilwood sandstone. Along the reef margin of the Hay River Bank, the Watt Mountain "shale" becomes difficult to identify and its recognizable limit is illustrated (from Williams, 1981).
Regional schematic cross section illustrating the stratigraphy of the Beaverhill Lake Group, based on master cross section A-A' (Fig. 11.8).
Beaverhill Lake Group paleogeography and facies maps, illustrating the development through time of the Beaverhill Lake sequence. The transgressive sequence is depicted in a to c and the regressive sequence in d. The initial transgression (a) deposited a marginal-marine unit (Watt Mountain Formation). Arkosic sandstones (Gilwood Member) were deposited as a fluvial-deltaic system that prograded into the marginal-marine body of water flanking the Peace River Arch. The Dawson Bay Basin was infilled by a deepening-upward transgressive sequence (Dawson Bay Formation). An incursion of open-marine waters from the east is postulated because of the presence of normal-marine fauna in the Dawson Bay Formation. In the northern part of the basin open-marine carbonate sedimentation continued with minimal influence of the post-Elk Point hiatus, particularly along the bank margin. Relative sea level continued to rise, resulting in restricted-marine conditions over the majority of the basin (b). The facies change from open-marine to restricted-marine to continental sedimentation in a southeasterly direction indicates a southward-advancing seaway. A tidal flat to continental facies flanked the Peace River Arch and basinal conditions existed in the Horn River Basin. By the time of Slave Point deposition, marine conditions developed over most of the Elk Point Basin (c). The development of a shallow-marine carbonate platform provided a substrate for subsequent reef growth. Carbonate bank complexes overlying the Elk Point bank complex developed in the northern part of the basin (Hay River Bank) and flanking the Peace River Arch and West Alberta Ridge. The bank complexes consist of a number of shallowing-upward reefal cycles that formed in response to episodic pulses of relative sea-level rise. The intra-platform basin (Waterways Basin) was a site of basinal to off-reef sedimentation during this time. Restricted-marine carbonates equivalent to the Slave Point platform were deposited in the southern part of the basin. The intra-platform basin became infilled by the regressive sequence (d). A shelf complex developed in southern Saskatchewan (Souris River Shelf), consisting of a series of shallowing-upward carbonate-evaporite cycles (Souris River Formation). These cycles grade laterally northwestward to shallowing-upward shale-carbonate clinothem cycles that were deposited in a basin to slope depositional setting. The clinoforming cycles depositionally downlap the transgressive reef complexes. Basinal conditions existed within the Horn River Basin.
Stratigraphic cross section H-H', illustrating Beaverhill Lake and Elk Point stratigraphy from the barrier margin of the Hay River Bank southward, as the whole succession onlaps the Peace River Arch. The Elk Point stratigraphy is illustrated because of the interrelationship of the two groups in this area. Shallow-marine carbonates of the transgressive sequence (Slave Point Formation) thin southward as they onlap the Peace River Arch. Hamburg (3-33-96-11 W6M) and Cranberry (not illustrated) are significant gas pools within the Slave Point Formation (Fig. 11.3) that developed as reef complexes within the Hotchkiss Embayment, or along the northern bank margin of the Peace River Arch Fringing Reef Complex. The Slave Point Formation is pervasively dolomitized along the bank margin of the Hay River Bank and marginal to embayments within the underlying Elk Point Bank complex (i.e., Klua Embayment, represented by b-19-G; 94-J-9). The upper part of the bank complex (Slave Point Formation) prograded farther basinward over the underlying Elk Point bank margin. The regressive phase (Waterways Formation) onlapped the Hay River Bank margin to the north and the Peace River Arch to the south. It infilled the local paleotopography of the underlying bank complex (i.e., Hotchkiss Embayment). Note that the vertical scale (1:6800) is slightly contracted from the Atlas standard (1:6000) and the horizontal scale expanded. Line of section H-H' is shown on Figure 11.18.
Paleogeographic map of the Horn River Basin and Hay River Bank. The reef margin of the transgressive phase (Slave Point), the basinal reefs, and the depositional limit of the regressive phase (Waterways Formation) are illustrated. Where the underlying Elk Point barrier margin is not coincident with the Slave Point reef margin it is illustrated separately.
Stratigraphy of the Peace River Arch Fringing Reef Complex. The bank complex of the transgressive phase developed in a backstepping manner and is composed of several shallowing-upward "reefal" cycles. The stratigraphy is based on interpretations by Gosselin et al. (1989) for Evi, Dunham et al. (1983) for Slave, and unpublished regional stratigraphy by the senior author. The paleotopography of the Precambrian surface influenced the development of the bank complex. The clinothems of the regressive phase onlap (downlap) the bank complex and the paleo-landmass. Line of section J-J' is shown on Figure 11.20.
Peace River Arch Fringing Reef Complex paleogeographic map illustrating the bank margins, depositional edges and isopachs of the transgressive phase. The locations of sections J-J' (Fig. 11.19) and C*-C' (Fig. 11.10) and major Slave Point oil pools are indicated.
Swan Hills Complex paleogeographic map illustrating the cycle 1 and 2 bank margins of the transgressive phase. Younger "reefal" cycles developed aggradationally on the cycle 1 and 2 banks, but are not illustrated in detail (refer to Jansa and Fischbuch, 1974). The bank margins are modified from previous workers, mainly Jansa and Fischbuch (1974).
Stratigraphic cross section K-K', portraying the stratigraphy of the transgressive sequence across the Swan Hills Complex. The cross section is taken from Jansa and Fischbuch (1974) with the depositional facies simplified. Line of section K-K' is shown on Figure 11.21.
Caroline area stratigraphic cross section L-L'. The Swan Hills Complex marginal to the West Alberta Ridge in the Caroline area developed as a series of westward backstepping, shallowing-upward "reefal" cycles. A high-energy reefal facies developed along the bank margin of each cycle. Westward, the Swan Hills reef complex merges and becomes difficult to distinguish from overlying carbonates of the Woodbend Group. The regressive sequence (Waterways Formation) downlapped the transgressive reef complex in a westward direction.
Peace River Arch Fringing Reef Complex - Swan Hills Complex correlation panel. Correlation of the transgressive reef cycles from the Peace River Arch Fringing Reef Complex and the Swan Hills Complex represents the senior author's interpretation. A relative sea-level curve is presented for the transgressive sequence. Each cycle was initiated by a relative sea-level rise. As the rate decreased the bank grew to sea level, forming the characteristic shallowing-upward "reefal" cycle.
Table 11.3a (as text) (as image)
Oil production from the Beaverhill Lake Group.
Table 11.3b (as text) (as image)
Gas production from the Beaverhill Lake Group.
