Vanguard Formation
Stratigraphic range: Callovian to Oxfordian
TypeGeological formation
Sub-unitsMasefield Shale
Roseray Formation
Rush Lake Shale
UnderliesMannville Group
OverliesShaunavon Formation
Thicknessup to 180 metres (590 ft)[1]
Lithology
PrimaryShale, sandstone
Location
Coordinates49°22′N 107°47′W / 49.36°N 107.79°W / 49.36; -107.79 (Vanguard Formation)
RegionWCSB, Williston Basin
Country Canada
 United States
Type section
Named forVanguard, Saskatchewan
Named byMilner & Thomas
Year defined1954
Vanguard Formation is located in Canada
Vanguard Formation
Vanguard Formation (Canada)

The Vanguard Formation is a stratigraphical unit of Callovian to Oxfordian age in the Western Canadian Sedimentary Basin.

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]

Distribution

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

Relationship to other units

The Vanguard Formation is unconformably overlain by the Mannville Group and disconformably overlays the Shaunavon Formation.[1]

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

Subdivisions

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

References

  1. ^ a b c d Lexicon of Canadian Geologic Units. "Vanguard Formation". Retrieved 2010-01-01.
  2. ^ 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
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