| Clearwater Formation Stratigraphic range: Albian |
|
|---|---|
| Type | Geological formation |
| Unit of | Mannville Group |
| Sub-units | Wabiskaw Member |
| Underlies | Grand Rapids Formation |
| Overlies | McMurray Formation |
| Thickness | up to 85 metres (280 ft)[1] |
| Lithology | |
| Primary | Shale, sandstone |
| Location | |
| Named for | Clearweater River |
| Named by | R.G. McConnell, 1893 |
| Region | north-eastern and central Alberta |
| Country | Canada |
The Clearwater Formation is a stratigraphical unit of Albian age in the Western Canadian Sedimentary Basin.
It takes the name from Clearweater River. The formation is exposed on the banks of the Athabasca River between Brule Falls and Boiler Falls, as well as along the Christina River, a tributary of the Clearwater River. It was first defined by R.G. McConnell in 1893.[2]
Contents |
The Clearwater Formation consists of black and green shale and sandstone interbeds. In the Cold Lake area it contains bituminous sands. The Wabiskaw Member consists of glauconitic sandstone.
Heavy Oil is produced from the Wabiskaw Member of the Clearwater Formation in the Wabasca Oil Field. The formation contains bitumenous sand in the Cold Lake and Primrose Lake region.
The Clearwater Formation occurs in the sub-surface of north-eastern and central Alberta, and is exposed on lower course of the Athabasca River as well as on the banks of the Christina River, south-east of Fort McMurray. It reaches a maximum thickness of 85 metres (280 ft) on the Athabasca River, thins out to 6 metres (20 ft) in the Cold Lake area, and wedges out towards the south. It is not present south of Edmonton.[1]
The Clearwater Formation is conformably overlain by the Grand Rapids Formation and conformably overlays the McMurray Formation. It is equivalent to the Bluesky Formation and the lower Spirit River Formation in the Peace River region, may be equivalent to the Cummings Member in the Lloydminster region, and corresponds to parts of the Manville Group in central Alberta.[1]
The Wabiskaw Member occurs at the base of the Clearwater Formation, and is a thin sandstone bed characterized by the presence of glauconite. A thin fissile shale bed occurs at its base, and separates it from the underlying McMurray Formation.[3]
It was defined in well Barnsdall West Wabiskaw No. 1 (located between Wabasca River and Lesser Slave Lake in central Alberta) by P.C. Badgley in 1952.[4] Heavy oil is extracted from the loose sandstone by means of horizontal drilling in the Wabasca Oil Field.
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