The Mannville Group is a stratigraphical unit of Cretaceous age in the Western Canadian Sedimentary Basin.
| Mannville Group | |
|---|---|
| Stratigraphic range: Early Cretaceous | |
| Type | Geological group |
| Sub-units | Glauconitic Sandstone, Ostracod Beds, Ellerslie Member, Grand Rapids Formation, Clearwater Formation, McMurray Formation, Waseca Sand, Sparky Sand, General Petroleum Sand, Rex Sand, Lloydminster Sand, Cummings Member, Dina Member, Pense Formation, Cantuar Formation, Success Formation |
| Underlies | Colorado Group |
| Overlies | Rundle Group, Banff Formation, Wabamun Formation |
| Thickness | up to 145 metres (480 ft)[1] |
| Lithology | |
| Primary | Sandstone |
| Other | Shale |
| Location | |
| Coordinates | 53.3087°N 111.1541°W |
| Region | Alberta, Saskatchewan |
| Country | Canada |
| Type section | |
| Named for | Mannville, Alberta |
| Named by | Nauss, 1945 |
It takes the name from the town of Mannville, Alberta, and was first described in the Northwest Mannville 1 well by A.W. Nauss in 1945.[2]
Lithology
The Mannville Group consists of interbedded continental sand and shale in the base, followed by a calcareous sandstone member, marine shale, glauconitic sandstone and salt and pepper sandstone. An additional non-marine sequence is present in north-eastern Alberta.
Hydrocarbon production
Bitumen is produced from the McMurray Formation at the Athabasca Oil Sands. Heavy Oil is produced from the Wabiskaw Member of the Clearwater Formation in the Wabasca oil field, and from multiple formations in the Lloydminster and Provost areas in eastern Alberta and western Saskatchewan. Natural gas is extracted from the Ostracod and Glauconite beds in southern Alberta, and light oil is extracted from the Ellerslie Member in central and southern Alberta. Multiple oil fields[3] and gas fields[4] tap into the Manville Group.
Total gas reserves amount to 316799×106 m3 in the Lower Mannville and 644774×106 m3 in the Upper Mannville.[5] Recoverable oil reserves amount to 105.64×106 m3 in the Lower Mannville and 199.20×106 m3 in the Upper Mannville.[6]
Distribution
The Mannville Group reaches a thickness of 145 feet (40 m) in its type locality. It occurs in the sub-surface in central Alberta, extending east-west from Edmonton to Lloydminster and north-south from the Deep Basin to the United States border. It is present in the sub-surface in west-central and southern Saskatchewan.
Relationship to other units
The Mannville Group is discomformably overlain by the Joli Fou Formation shale of the Colorado Group. It rests unconformably on the older Paleozoic carbonates.
It is correlated with the lower Blairmore Group in the Canadian Rockies foothills and to the Bullhead Group and the Spirit River Formation of the Fort St. John Group in north-western Alberta. It is also equivalent to the Cantuar Formation in Saskatchewan and the Swan River Formation in Manitoba.
Subunits
The Mannville Group includes the following sub-units:
Central and southern Alberta
| Subdivision | Sub-unit | Age | Lithology | Max Thickness | Reference |
|---|---|---|---|---|---|
| Upper | Upper Mannville | marine shale and sandstone | |||
| Glauconitic Sandstone | Early Cretaceous | very fine to medium grained quartz sandstone with siderite and glauconite | 35 m (110 ft) | [7] | |
| Lower Mannville | |||||
| Ostracod Beds | Early Cretaceous | Unit A: shale and fossiliferous limestone Unit B: argillaceous limestone with ostracod fossils Unit C: dark shale with siltstone and sandstone interbed Unit D: fine to medium grained lithic calcareous sandstone with kaolinite and chert | 40 m (130 ft) | [8] | |
| Ellerslie Member | Early Cretaceous | Upper: fine grained sand with sandy shale and shaley sand lenses Lower: medium grained quartz sand, siltstone, coal | 40 m (130 ft) 30 m (100 ft) |
[9] | |
| Detrital Beds | Early Cretaceous | Chert pebbles, lithic sandstone, shale, siltstone | 70 m (230 ft) | [10] | |
- In southern Alberta, the Ellerslie Member is replaced by the Sunburst Member, Taber Sandstone, and Cutbank Sandstone.
Athabasca region
| Sub-unit | Age | Lithology | Max Thickness | Reference |
|---|---|---|---|---|
| Grand Rapids Formation | Albian | bitumenous fine to medium sand (A, B and C sands, separated by silt and shale) | 125 m (410 ft) | [11] |
| Clearwater Formation | Albian | black and green shales and sand | 85 m (280 ft) | [12] |
| Wabiskaw Member | Albian | glauconitic sands with black fissile shale | 35 m (110 ft) | [13] |
| McMurray Formation | late Barremian to Aptian | fine grained bituminous sands | 60 m (200 ft) | [14] |
Lloydminster region
| Sub-unit | Age | Lithology | Max Thickness | Reference |
|---|---|---|---|---|
| Colony Sand | Early Cretaceous | friable glauconitic and argillaceous sandstone | 15 m (50 ft) | [15] |
| McLaren Member | Early Cretaceous | very fine grained sandstone and shale | 18 m (60 ft) | [16] |
| Waseca Sand | Early Cretaceous | sand with silt and shale | 25 m (80 ft) | [17] |
| Sparky Sand | Early Cretaceous | sand and shale | 12 m (40 ft) | [18] |
| General Petroleum Sand | Early Cretaceous | very fine to fine grained quartzose sand | 15 m (50 ft) | [19] |
| Rex Sand | Early Cretaceous | very fine to fine grained quartzose sand with silt and shale | 14 m (50 ft) | [20] |
| Lloydminster Sand | Early Cretaceous | unconsolidated quartz sand with silt | 30 m (100 ft) | [21] |
| Cummings Member | Early Cretaceous | shale with beds of salt-and-pepper sandstone | 27 m (90 ft) | [22] |
| Dina Member | Early Cretaceous | quartz sandstone with siltstone and shale | 60 m (200 ft) | [23] |
Southern Saskatchewan
References
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