Unit Name: Cadotte Member
Unit Type: Lithostratigraphic
Rank: Member
Status: Formal
Usage: Currently in use
Age Interval: middle Albian (108.8 - 106.4 ma)
Age Justification: The Cadotte sand carries the ammonite Gastroplites and Inoceramus cadottensis as well as other molluscs and starfish. Singh (1971) reported an extensive microflora with primitive angiosperm pollen. Wickenden (1951) described an extensive arenaceous microfauna from the Cadotte.
Province/Territory: Alberta
Originator: McLearn, 1944.
Type Locality:
The Alberta Study Group (1954) suggested Wickenden's (1951) section on the north side of a small tributary valley to Peace River about 150 m (492 ft) from the water's edge on the west side of Peace River in NE/4 Sec. 25 or SE/4 Sec. 26, Twp. 85, Rge. 21W5M.
Distribution:
The thickness varies from 12 to 52 m (29 to 171 ft), with an average of around 25 m (82 ft) in the Peace River region, thinning to the north and east from the Peace River town-Pouce Coupe-Grande Prairie area. Change to continental facies to the south makes separation of this unit from the Paddy difficult in the area south of Grande Prairie. North of Twp. 93 the sandstone passes into the shale facies of the Fort St. John Group.
Locality Data:
Thickness(m): Minimum 12, Maximum 52, Typical 25.
Lithology:
Grey to light grey to greenish grey, fine- to very fine-grained, friable to firm, locally calcareous or sideritic, often glauconitic, salt-and-pepper sandstone with good porosity. Rare chert pebbles occur. Sometimes interbedded with dark grey marine shale and silt.
Relationship:
The Cadotte is conformable with the underlying Harmon Member of the Peace River Formation. It is overlain disconformably by the Paddy Member south of Twp. 88 and unconformably by the Shaftesbury Formation north of Twp. 88. It correlates in part with the upper Scatter Sandstone (Tussock Member, Stott, 1981) of the Muskwa area of northeastern British Columbia, and with part of the lower Lepine Formation. The basal part of the Boulder Creek Member of the Commotion Formation of the Pine Pass area is equivalent to the Cadotte Member of the Pine Pass area and the Peace River Canyon.
History:
McLearn's original name included all of the upper sandstone member of the Peace River Formation, but Wickenden (1951) restricted the term Cadotte to the lower marine portion and proposed the term Paddy for the continental upper portion.
Other Citations:
McLearn, 1918.
References:
Alberta Study Group, 1954. Lower Cretaceous of the Peace River region. In: Western Canada Sedimentary Basin; Clark, L.M. (Ed.). Amer. Assoc. Petrol. Geol., p. 268-278.
McLearn, F.H., 1918. Peace River Section, Alberta; Geological Survey of Canada, Summary Report 1917, Part C, pp. 14-21.
McLearn, F.H., 1944. Revision of the Lower Cretaceous of the western Interior of Canada; Geological Survey of Canada, Paper 44-17, 6 p.
Singh, Chaitanya, 1971. Lower Cretaceous Microfloras of the Peace River Area, Northwestern Alberta, 2 Vols; Research Council of Alberta, Bulletin 28, 542 p.
Stott, D.F., 1981. Lower Cretaceous Fon St. John Group and Upper Cretaceous Dunvegan Formation, foothills and plains, Alberta, British Columbia, District of Mackenzie and Yukon Territory. Geological Survey of Canada, Bulletin 328.
Wickenden, R.T.D., 1951. Some Lower Cretaceous sections on Peace River below the mouth of Smoky River, Alberta (Report, Plate and Figure); Geological Survey of Canada, Paper 51-16, 47 p.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: C.R. Stelck
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 21 Jul 2009