Carboniferous biostratigraphy and correlation, northeastern British Columbia and southwestern District of Mackenzie

Regional stratigraphic and fauna distribution data from 5 surface stratigraphic sections and 37 subsurface sections indicate the following ages and stratigraphic relationships within the Lower Carboniferous succession of the area. The Banff Formation (Early? and Middle Tournaisian, Plains), which consists of shale with minor amounts of siltstone and limestone, passes westward into equivalent shale and chert of the Besa River Formation. The Pekisko Formation (Middle Tournaisian, Plains), composed of skeletal limestone and wackestone, and the "Shunda'' Formation (Late Tournaisian, Plains), comprising argillaceous limestone, calcareous shale and minor amounts of skeletal and pelletoid limestone, change facies westward, near the eastern edge of the disturbed belt, into the upper Besa River Formation and Member A of the Prophet Formation, and are equivalent to the upper Clausen and lower Flett formations to the north (southern Mackenzie Mountains). The lower member of the Debolt Formation (Early and Early Middle Visean, Plains), composed of micritic and skeletal limestone, wackestone and calcareous shale, grades westward into the cherty dolomite and limestone of Member B of the Prophet Formation and is correlated with the limestone and calcareous shale of the middle Flett Formation. The upper member of the Debolt Formation (Late Middle and Early Late Yisean, Plains) consists of pelletoid, micritic, argillaceous and skeletal limestone with minor amounts of calcareous shale and dolomite, and is correlative with the cherty, skeletal limestone of Member C and the upper part of Member B of the Prophet Formation, and with the skeletal limestone and calcareous shale of the upper Flett Formation. The cherty carbonates of the Prophet Formation(Late? Tournaisian to Early Late Yisean) occur in the outcrop belt and westernmost plains of northeastern British Columbia and change facies into the Besa River Formation by a progressive increase in shale and chert from base to top toward the west. The Stoddart Group (Early Late Vi sean to Pennsylvanian), which consists of terrigenous elastics and carbonates, occurs in the plains and outcrop belt of northeastern British Columbia, and grades northward into the coarse-grained, partly continental elastics of the Mattson Formation, and westward into the shale of the Besa River Formation. Eleven Middle Tournaisian to Late Yisean foraminiferal zones within the area correspond to zones previously established for the North American Cordillera, and correlate with the original Lower Carboniferous stratigraphic sequence of Eurasia. There is a consistent relationship between the vertical and lateral distribution of foraminiferal zones and associated macro faunal assemblages. With minor exceptions, the combined fauna succession of this area matches that in southwestern Alberta and western United States and forms part of a consistent biostratigraphic scheme applicable to Lower Carboniferous rocks throughout western North America.