Baldonnel Formation

Baldonnel Formation Stratigraphic range: Carnian PreЄ Є O S D C P T J K Pg N
Type	Geological formation
Unit of	Schooler Creek Group
Sub-units	Ducette Member
Underlies	Pardonet Formation, Fernie Formation
Overlies	Charlie Lake Formation
Thickness	up to 146 metres (480 ft)[1]
Lithology
Primary	Limestone, dolostone
Other	Siltstone, sandstone
Location
Named for	Baldonnel, British Columbia
Named by	L.M. Clark, 1957
Coordinates	56°06′51″N 122°48′39″W / 56.11404°N 122.81095°W / 56.11404; -122.81095 (Baldonnel Formation)Coordinates: 56°06′51″N 122°48′39″W / 56.11404°N 122.81095°W / 56.11404; -122.81095 (Baldonnel Formation)
Region	Alberta,  British Columbia
Country	Canada

The Baldonnel Formation is a stratigraphical unit of Carnian age in the Western Canadian Sedimentary Basin.

It takes the name from the hamlet of Baldonnel, British Columbia, and was first described in the Pacific Fort St. John No. 16 well by L.M. Clark in 1957.^[2] A surface type locality can be found at Brown Hill, on the north shore of Williston Lake, at 56°06′51″N 122°48′39″W / 56.11404°N 122.81095°W / 56.11404; -122.81095 (Baldonnel Formation).

Lithology

The upper unit of the Baldonnel Formation consists of grey massive limestone and dolostone in the Canadian Rockies foothills and in the western range between the Liard River and Peace River. Siltstone and fine grained sandstone occur as interbeds.

In the sub-surface of the Peace River Country, the Baldonnel Formation is represented by porous and permeable dolostone.

Oil and gas production

Gas is produced from the Baldonnel Formation in north-eastern British Columbia.^[3]

Distribution

The Baldonnel Formation occurs in outcrops in the Williston Lake area of the Canadian Rockies, and in the sub-surface from the Liard River to the Peace River Country.

It reaches a maximum thickness of 146 metres (480 ft) south of Hudson's Hope.

Relationship to other units

The Baldonnel Formation is the middle member of the Schooler Creek Group. It is conformably overlain by the Pardonet Formation limestone and siltstone or unconformably overlain by the Fernie Formation shale. North of the Williston Lake it overlies the dolomite beds of the Charlie Lake Formation.

It is equivalent to the upper parts of the McLearn Formation and Ludington Formation. It can also be correlated with the Winnifred Member of the Whitehorse Formation in central Alberta.

Ducette Member

The lower unit is designated as Ducette Member.^[4] It occurs only in the south-west of the range, between the Liard River and the Peace River.

It is composed of argillaceous siltstone, very fine grained sandstone and limestone.

References

1. ^ Lexicon of Canadian Geologic Units. "Baldonnel Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:000714. Retrieved 2009-02-14. 
2. ^ Clark, L.M., 1957. Fort St. John sets pace for Peace River gas fields. Oil and Gas Journal, v. SS, no. 33, p.132-134.
3. ^ Canadian Society of Petroleum Geologists, Bulletin of Canadian Petroleum Geology; v. 52; no. 4; p. 277-301; DOI: 10.2113/52.4.277 (December 2004). "Hydrocarbon source rock characterization and thermal maturity of the Upper Triassic Baldonnel and Pardonet formations, northeastern British Columbia, Canada". http://bcpg.geoscienceworld.org/cgi/content/abstract/52/4/277. Retrieved 2009-02-14. 
4. ^ Lexicon of Canadian Geologic Units. "Ducette Member". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004228. Retrieved 2009-02-14. 

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