Kaskapau Foraminifera from Peace River Area of Western Canada

The Peace River area of western Canada has a Lower Cretaceous marine succession of strata of boreal affinities. The contained boreal microfauna is distinct from the partly correlative Comanchean faunas of the Gulf of Mexico. Gulf of Mexico faunas did not appear in western Canada until the Lower Turanian stage of the Upper Cretaceous. The Lower Turonian microfauna serves, then, as a common datum for North American strata and this microfauna is found in the Peace River area in the central part of the Kaskapau formation.

The central Kaskapau microfaunas are of mixed pelagic and benthonic assemblages. The ancestry of the benthonic assemblages is contained, for the most part, in the history of Lower Cretaceous microfaunas peculiar to the boreal floodings. The Gulf Coast floodings introduced the pelagic element. The pelagic element is dominated by the species of Gimbelina, Gimbelitria, and Globigerina. This latter fauna can be readily dated by the contained magafauna of Inoceramus labiatus, which places the pelagic fauna, in terms of the European section, in Lower Turonian. The identification of the pre-Turonian beds may be made by the ammonite genus, Dunveganoceras, which has been found at the top of the Cenomanian beds in England (Wright and Wright 1951, p. 29). In western Canada, Dunveganoceras is found around 200 to 250 feet below the occurrence of Inoceramus labiatus and identification of the Cenomanian-Turonian boundary is dependent rather on the spectrum of the microfauna as ammonites are rare at this interval.

The boundary between the Cenomanian has been arbitrarily set at the horizon of introduction of the pelagic fauna into the microfaunal assemblages. This earliest Turonian pelagic microfaunal assemblage is outlined and described in this paper.

The pelagic species have already been recorded from the Gulf Coast Formanifera microfauna by Cushman (1946). The benthonic species are mainly new.