The Mannville Group is a stratigraphic unit of Cretaceous age in the Western Canadian Sedimentary Basin.
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.Nauss, Arthur William, 1945. Cretaceous stratigraphy of Vermilion area, Alberta, Canada; American Association of Petroleum Geologists (AAPG), AAPG Bulletin, vol. 29, no. 11 (November), pp. 1605-1629.
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 and gas fields tap into the Manville Group.
Total gas reserves amount to in the Lower Mannville and in the Upper Mannville. Recoverable oil reserves amount to in the Lower Mannville and in the Upper Mannville.
Distribution The Mannville Group reaches a thickness of 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 Maxthickness ReferenceUpperUpper Mannville marine shale and sandstone Glauconitic Sandstone Early Cretaceous very fine to medium grained quartz sandstone with siderite and glauconite Lower Mannville Ostracod Beds Early Cretaceous Unit A: shale and fossiliferous limestoneUnit B: argillaceous limestone with ostracod fossilsUnit C: dark shale with siltstone and sandstone interbedUnit D: fine to medium grained lithic calcareous sandstone with kaolinite and chert Ellerslie Member Early Cretaceous Upper: fine grained sand with sandy shale and shaley sand lensesLower: medium grained quartz sand, siltstone, coal Detrital Beds Early Cretaceous Chert pebbles, lithic sandstone, shale, siltstone In southern Alberta, the Ellerslie Member is replaced by the Sunburst Member, Taber Sandstone, and Cutbank Sandstone.
Athabasca region Sub-unit Age Lithology Maxthickness Reference Grand Rapids Formation Albian bitumenous fine to medium sand (A, B and C sands, separated by silt and shale) Clearwater Formation Albian black and green shales and sand Wabiskaw Member Albian glauconitic sands with black fissile shale McMurray Formation late Barremian to Aptian fine grained bituminous sands
Lloydminster region Sub-unit Age Lithology Maxthickness Reference Colony Sand Early Cretaceous friable glauconitic and argillaceous sandstone McLaren Member Early Cretaceous very fine grained sandstone and shale Waseca Sand Early Cretaceous sand with silt and shale Sparky Sand Early Cretaceous sand and shale General Petroleum Sand Early Cretaceous very fine to fine grained quartzose sand Rex Sand Early Cretaceous very fine to fine grained quartzose sand with silt and shale Lloydminster Sand Early Cretaceous unconsolidated quartz sand with silt Cummings Member Early Cretaceous shale with beds of sandstone Dina Member Early Cretaceous quartz sandstone with siltstone and shale
Southern Saskatchewan Sub-unit Age Lithology Maxthickness Reference Pense Formation Albian fine grained sandstone, clay, shaly silt Cantuar Formation Aptian to Albian mudstone and sandstone Success Formation Jurassic to Lower Cretaceous quartzose sandstone and siltstone
References