Biostratigraphy of Frasnian (upper Devonian) strata in western Canada, based on conodonts and rugose corals

A total of 13 conodont zones and 11 rugose coral faunal assemblages current ly provides a subdivision of the Frasnian of the Western Canada Sedimentary Basin. The conodont zonation adopted is that first developed in the Montag ne Noire area of southern France and subsequently found to have widespread applicability, especially when supplemented through the use of graphic corr elation. The rugose coral faunal scheme is based on the overlapping ranges of species with wide geographic distribution, but with relatively short str atigraphic duration. Integration of these faunal schemes allows for more pr ecise biostratigraphic control and provides a basis for refined correlation of the sequences of basin fill. As all fossil groups have varying degrees of facies control on their distri bution, we do not have conodont and coral biostratigraphic data for all uni ts in the basin. Significant conodont data have been obtained mainly from t he margins of the larger bank and reef complexes, rather than their relativ ely shallow water interiors, and from the basinal strata enclosing them. Th ese data generally support a reciprocal process of reef and off-reef sedime ntation throughout the Frasnian. Rugose corals are most commonly developed within the reef and bank complexes (especially the Winterburn Group and equ ivalents), and particularly near their margins. They are rarer and of less biostratigraphic value in basinal strata. Some of the more significant formational time spans, expressed in terms of Montagne Noire (MN) Frasnian conodont zones, are summarized as follows. The Beaverhill Lake Group of Alberta ranges from the norrisi Zone of the lates t Middle Devonian to lower Zone 5. The succeeding Cooking Lake-Majeau Lake interval is in Zone 5 to possibly lower Zone 6, and the overlying Duvernay Formation extends into Zone 10. The Perdrix Formation in outcrop of the Roc kies is largely equivalent in age to the Cooking Lake-Majeau Lake-Duvernay, but locally at least ranges into lower Zone 11. The black/grey shale facie s of District of Mackenzie and northeast British Columbia (Canol Formation, Horn River Group) ranges at least as high as Zone 6 and locally as high as Zone 10. The Ireton, Leduc, Peechee, lower Mount Hawk interval of Alberta extends through Zone II, while most of the Nisku, Arcs/Grotto and upper Mou nt Hawk lie within Zone 12. The "Z-marker" within the elastic basin fill of subsurface Alberta lies approximately at the boundary of Zones 11 and 12. In the southern District of Mackenzie and northeast British Columbia, the J ean-Marie Member and equivalents are in Zone 12. Finally, the Blue Ridge, S imla, Kakisa and equivalents lie primarily within Zone 13.