Unit Name: Skoki Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Early Ordovician - Middle Ordovician (488.3 - 460.9 ma)
Age Justification: Brachiopods, gastropods, conodonts, cephalopods, trilobites, echinoderm fragments. Three brachiopod zones (Hesperonomia, Orthidiella, Anomalorthis) present in the southern Rockies, in addition younger horizons with corals are present in the central and northern Rockies.
Province/Territory: Alberta

Originator: Walcott, 1928

Type Locality:
Skoki Mountain (51°32'N, 116°03'W), southwestern Alberta. The type section is incomplete and the standard reference section is at Mount Wilson (52°00'N, 16°45'W), southwestern Alberta (Norford, 1969, p. 12, 56, 57).

Distribution:
The Skoki is widespread in the carbonate facies of the southern Rocky Mountains [Kananaskis Lakes, Calgary, Golden and Brazeau map-areas (82J, N, O; 83C)] where its observed thicknesses are between 62 and 186 m (204 and 610 ft). Westwards its place is taken by Glenogle Shales of the graptolitic facies. Northwestward and eastward the Skoki is cut out beneath the sub-Devonian unconformity, but in the central and northern Rocky Mountains a much thicker succession (up to 550 m, 1,800 ft) of similar Carbonates has been mapped as the Skoki Formation in the McBride, Monkman Pass, Pine Pass, Halfway River, Trutch and Ware map-areas (93H, I, O; 94B, F, G).

Lithology:
Resistant dolomites and rare limestones, quartz silt and sand in many beds, some with dark brown, wispy, argillaceous layers. Oncolites common in beds near the top of the formation in the southern Rockies and at many levels in the central and northern Rockies.

Fossils:
Brachiopods, gastropods, conodonts, cephalopods, trilobites, echinoderm fragments.

Relationship:
Basically conformable with the underlying Tipperary Quartzite and Outram Formation, the latter contact locally gradational and diachronous. The upper contact with the Owen Creek Formation is paraconformable at most localities, but channel fillings and indications of karst topography are present at some outcrops.

References:
Norford, B.S., 1969. Ordovician and Silurian stratigraphy of the southern Rocky Mountains; Geological Survey of Canada, Bulletin 176, 90 p.
Walcott, C.D., 1928. Pre-Devonian Paleozoic formations of the Cordilleran provinces of Canada; Cambrian geology and paleontology, Part S. Smithsonian Miscellaneous Collections, vol. 75, no. 5, p. 175-368.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: B.S. Norford
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 Mar 2014