Unit Name: Mistaya Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Late Cambrian (499 - 488.3 ma)
Age Justification: The contained trilobite fauna is from the Saukia Zone, of latest Trempealeauan age.
Province/Territory: Alberta; British Columbia
Originator: Greggs, 1962; Aitken and Greggs, 1967
On the southwest slopes of Mount Murchison, overlying the type section of the Bison Creek Formation, in Alberta.
The Mistaya is 102 m (335 ft) thick at the type section; slightly thicker at Tangle Ridge and over 158 m (500 ft) at Mount Forbes. Since the Mistaya can only be mapped where the underlying Bison Creek Formation can be recognized it has the same distribution as the Bison Creek. Both formations merge to the north into the upper Lynx Group. The Mistaya is recognizable, about 61 m (200 ft) thick in the Sawback and Bourgeau ranges.
Thickness(m): Typical 102.
Generally resistant, cliff forming, thin-bedded, dense, silty Carbonates rather dolomitic in the lower beds. The upper beds are mainly of medium to very thick, massive, fine- to coarse-grained biocalcarenite. Large algal stromatolites (Collenia) are common; minor lithologies include oolitic beds, limestone pebble conglomerates and occasional cherty layers.
The lower contact of the Mistaya is gradational with the upper shales of the Bison Creek Formation; the upper contact is marked by an abrupt change from carbonates to greenish grey weathering shales (the lowest unit of Walcott's type Mons).
Beds of the Mistaya Formation were occasionally included by Walcott in his Mons Formation (unit 16), but he appears not to have recognized it as a distinct rock unit.
Aitken, J.D. and Greggs, R.G., 1967. Upper Cambrian formations, southern Rocky Mountains of Alberta, an interm report; Geological Survey of Canada, Paper 66-49, 91 p.
Greggs, R.G., 1962. Upper Cambrian biostratigraphy of the southern Rocky Mountains, Alberta; University of British Columbia, Vancouver, BC, Canada, Ph.D. thesis, 256 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: R.G. Greggs
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 Mar 2014