Unit Name: Wapiabi Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Campanian (83.5 - 70.6 ma)
Age Justification: Characterized by several zones of the ammonite Scaphites. The ammonites, generally not abundant, are associated with species of Inoceramus. The zones range from latest Turonian to Santonian, and the upper part of the formation is probably Campanian. Contains several foraminiferal assemblages, including agglutinated fauna, a distinctive foraminiferal and ostracode unit, and a pelagic microfauna of the upper or First White Speckled Shale of the Colorado Group of the plains (Wall and Germundson, 1963). The presence of Manicorpus calvus suggests a Campanian age (Jerzykiewicz and Norris, 1994).
Province/Territory: Alberta
Originator: Malloch, 1911.
Type Locality:
Although Malloch measured a section on Wapiabi Creek, much of the formation is not exposed there. Stott (1963, p. 18) outlined a type section on Thistle Creek, on the west flank of syncline in Sec. 17, Twp. 44, Rge. 20W5M, Alberta.
Distribution:
Extends along the foothills from the International Boundary to the Muskeg River. Occurs along the front ranges and extends eastward beneath the plains. Thickness ranges from 640.1 m (2100 ft) at the type locality to 319 m (1046 ft) at the Highwood River and in the order of 487.7 m (1600 ft) near the Smoky River.
Locality Data:
Thickness(m): Minimum 319, Maximum 640.1.
Lithology:
Dark grey to black marine shales, which in some parts contain abundant sideritic concretions, minor siltstone, sandstone and limestone. Throughout most of the foothills a unit of fine grained sandstone occurs near the top, i.e., the Chungo Member. The formation is divided into seven members by the presence of concretions, calcareous shale and sandstone; from the base upwards these are the Muskiki, Marshybank, Dowling, Thistle, Hanson, Chungo and Nomad.
Relationship:
Parent: Alberta Group. Overlies the Cardium Formation conformably or with only slight disconformity. The upper beds are gradational into the overlying Belly River Formation in the south and the Brazeau Formation in the central foothills. The unit passes eastward into shales of the upper Colorado Group and Lea Park Formation, to the north into the Puskwaskau, Bad Heart and Muskiki formations.
References:
Jerzykiewicz, T. and Norris, D.K., 1994, Stratigraphy, structure and syntectonic sedimentation of the Campanian 'Belly River' clastic wedge in the southern Canadian Cordillera, Cretaceous Research, v. 15, p. 367-399.
Malloch, G.S., 1911. Bighorn Coal Basin, Alberta; Geological Survey of Canada, Memoir 9, 78 p.
Stott, D.F., 1963. The Cretaceous Alberta Group and equivalent rocks, Rocky Mountain Foothills, Alberta. Geol. Surv. Can., Memoir 317.
Wall, J.H. and Germundson, R.K., 1963. Microfaunas, megafaunas, and rock-stratigraphic units in the Alberta Group (Cretaceous) of the Rocky Mountain Foothills; Bull. Can. Petrol. Geol., vol. 11, no. 4.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: D.F. Stott; P.H. Davenport
Entry Reviewed: No
Name Set: Lithostratigraphic Lexicon
LastChange: 17 Mar 2010