Cardium Formation
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| Cardium Formation | |
|---|---|
| Stratigraphic range: | |
 Photomicrograph of drill cuttings from Cardium Formation sandstone. | |
| Type | Geological formation |
| Unit of | Alberta Group, Colorado Group, Smoky Group |
| Sub-units | Sturrock Member, Leyland Member, Cardinal Member, Kiska Member, Moosehound Member, Ram Member. |
| Underlies | Wapiabi Formation |
| Overlies | Blackstone Formation, Kaskapau Formation |
| Thickness | 22 metres (70 ft) to 109 metres (360 ft)[1] |
| Lithology | |
| Primary | Sandstone |
| Other | Shale |
| Location | |
| Coordinates | 51°08′28″N 114°59′40″W / 51.14101°N 114.99446°W |
| Region | Western Alberta, and northeastern British Columbia |
| Country | Canada |
| Type section | |
| Named for | Cardium shells |
| Named by | James Hector, 1895[2] |
The Cardium Formation is a stratigraphic unit of Late Cretaceous age in the Western Canada Sedimentary Basin. It takes the name from the fossilized heart-shaped cockle shells in the family Cardiidae (from Greek καρδίᾱ kardiā, "heart") present. It was first described along the Bow River banks by James Hector in 1895.[2] It is present throughout western Alberta and in northeastern British Columbia, and it is a major source of petroleum and natural gas.[3][4]
The Cardium Formation is composed primarily of beds of massive, fine-grained to conglomeratic sandstone, which are separated by thick layers of shale. The formation is subdivided into the following members from top to base:
- Sturrock Member (sandstone)
- Leyland Member (shale)
- Cardinal Member (sandstone)
- Kiska Member (shale)
- Moosehound Member (shale)
- Ram Member (sandstone)
In central Alberta, the formation is divided into the Pembina River Member and Cardium Zone.
Distribution
The Cardium Formation was deposited during the Turonian and Coniacian stages of the Late Cretaceous along the western edge of the Alberta Foreland Basin.[3] It extends northward from the Canada-United States border to northeastern British Columbia near Dawson Creek, and eastward from the foothills of the Canadian Rockies into the plains of southern and central Alberta. Beyond there, the sandstones grade into shale. Thickness of Cardium sand varies between 5 and 30 meters in Alberta, Canada.[1]
Relationship to other units
Due to its large areal extent, the Cardium Formation falls within different stratigraphic groups in different regions (Alberta Group, Colorado Group, and Smoky Group). It is conformably overlain by the Wapiabi Formation and underlain by the Blackstone Formation. The formation is partly equivalent to the Kaskapau Formation.[1]