Vanguard Formation

Vanguard Formation
Vanguard Formation
Stratigraphic range: Callovian to Oxfordian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Masefield Shale; Roseray Formation; Rush Lake Shale
Underlies	Mannville Group
Overlies	Shaunavon Formation
Thickness	up to 180 metres (590 ft)
Lithology
Primary	Shale, sandstone
Location
Coordinates	49°22′N 107°47′W / 49.36°N 107.79°W
Region	WCSB, Williston Basin
Country	Canada; United States
Type section
Named for	Vanguard, Saskatchewan
Named by	Milner & Thomas
Year defined	1954
	Vanguard Formation (Canada)

It takes the name from Vanguard, and was first defined by R.L. Milner and G.E. Thomas in 1954.^[2]

Lithology

The Vanguard Formation is composed of calcareous shale with a median quartzose sandstone. ^[1]

The Vanguard Formation Lateral reaches a maximum thickness of 180 metres (590 ft) in the Williston Basin along the Saskatchewan/Montana border.^[1]

It is equivalent to the Ellis Group in Montana and North Dakota.

In south-western Saskatchewan, Vanguard has group status, and includes the following subdivisions (of formation rank):

^ ^a ^b ^c ^d Lexicon of Canadian Geologic Units. "Vanguard Formation". Retrieved 2010-01-01.
^ Milner, R.L. and Thomas, G E., 1954. Jurassic System in Saskatchewan. In: Western Canada Sedimentary Basin. American Association of Petroleum Geologists, p. 250-267