Paleogeographic Significance of Late Cretaceous Microfossil Assemblage from Buffalo Head Hills, Northern Alberta: ABSTRACT

Abstract

A small isolated outcrop of shale in the Buffalo Head Hills of north-central Alberta has yielded forams, radiolarians, and dinoflagellates. The assemblage is of Senonian, and most probably of Campanian age. The foraminiferal fauna, including Haplophragmoides fraseri, Verneuilinoides bearpawensis, Praebulimina carseyae, and Cassidella tegulata, suggests correlation with the upper Campanian Bearpaw Formation of southern Alberta. The radiolarian assemblage includes Spongurus (Spongurantha) sp., Spongodiscus cf. S. renillaeformis, Spongostaurus sp., Sethocyrtis sp., and Dictyomitra multicostata, all forms illustrated by H. R. Bergquist from the Schrader Bluff Formation of northern Alaska, for which a middle Senonian age is designated. Essentially the same assemblage is known rom the Bearpaw Formation in the Cypress Hills of southeastern Alberta. Among the dinoflagellates are Deflandrea victoriensis, Dinogymnium longicornis, and D. sibiricum--forms which are restricted to the Senonian. The stratigraphic position of this outcrop is from 100-200 ft above the Cenomanian Dunvegan Formation. The Senonian, or more specifically, the likely Campanian age of the outcrop suggests at least a marked condensation, if not a pronounced unconformity, in the area. The microfossil assemblage may be construed as evidence in support of J. A. Jeletzky's 1971 hypothesis that a connection existed between the Arctic and western interior regions through northern Alberta during the Santonian and Campanian. End_of_Article - Last_Page 660------------