Type Geological formation Country Canada Province British Columbia Overlies Montney Formation Primary Siltstone, Slate | Other Phosphate, Sandstone Named by J.H. Armitage, 1962 Named for Doig River Underlies Schooler Creek Group | |
Thickness up to 190 metres (620 ft) Region NW Alberta
NE British Columbia
SE Yukon | ||
The Doig Formation is a stratigraphical unit of middle Triassic age in the Western Canadian Sedimentary Basin.
Contents
It takes the name from Doig River, a tributary of the Beatton River, and was first described in the Texaco N.F.A. Buick Creek No. 7 well (located north-west of Fort St. John, east of the Alaska Highway) by J.H. Armitage in 1962. .
Lithology
The Doig Formation is composed of fine grained, grey argillaceous siltstone and dark calcareous shale. Nodular phosphates occur at the base of the formation. Anomalously thicker, Porous sandstone channels and bars are present locally in the upper units of the formation.
Hydrocarbon production
The Doig formation is an important source rock for the Triassic Halfway and Charlie Lake formations. Total organic carbon values in the "phosphate zone" at the base of the Doig are commonly greater than 4% by weight and can reach up to 11%. The "phosphate zone" is also a potential undeveloped shale gas reservoir with as much as 400 trillion cubic feet of natural gas in place. Oil and gas is also extracted from the Doig Formation in conventional reservoirs along the western Montney trend and in the Peace River Arch.
Distribution
The Doig Formation reaches a maximum thickness of 190 metres (620 ft) in the Canadian Rockies foothills it thins towards the north and east. It occurs in the sub-surface in north-western Alberta, north-eastern British Columbia and southern Yukon, from 53ºN and 118ºW to the Canadian Rockies.
Relationship to other units
The Doig Formation is unconformably overlain by the Halfway Formation of the Schooler Creek Group. The contact is marked by a dolomitic bed and a chert and quartz conglomerate bed. Westwards it is overlain by newer Jurassic beds. It conformably overlays the Montney Formation, which rests under the phosphate pellet bed located in the base of the Doig.
The formation correlates with the lower Llama Member of the Sulphur Mountain Formation in the southern ranges of the Canadian Rockies, with the Whistler Member of the Whitehorse Formation in the Muskwa Ranges, and with the Toad Formation in the upper Liard River area.