| Summary: | Sedimentary strata near Tate Lake, south of Norman Wells, N.W.T., were investigated using palynomorph analysis indicating the presence of Upper Maastrichtian and Paleocene beds. The Upper Maastrichtian sections contain tv/o local palynostratigraphic zones correlative with Srivastava's Wodehousea spinata and Manci-corpus gibbus zones of the Edmonton and Battle Formations of Alberta, and other Maastrichtian formations in western North America. The Paleocene strata compare lithologically and palynologically with the Lower Fort Union Group of Montana and Wyoming, the post-Brazeau beds of the Alberta Foothills, the upper part of the Bonnet Plume Formation, N.W.T., and Tertiary coal deposits in Spitzbergen. A progressive cooling in climate from subtropical to warm temperate during Upper Maastrichtian times is indicated by the decrease in the number of angiosperm species and greater influx of gymnosperms and pteridophytes, A marked change in microflora and lithology at the Cretaceous-Tertiary boundary indicates temperate conditions and increased rates of sedimentation in the Tate Lake area. Major lignite seams characteristic of the Paleocene strata probably were produced in freshwater swamps in one of the subsiding sedimentary basins formed along the east side of the Mackenzie Mountains during the Laramide orogeny. The Tate Lake strata appear to be part of the Hell Creek-Fort Union type formational sequences straddling the Cretaceous-Tertiary boundary indicating that climatic and sedimentary conditions were very similar all along the Rocky Mountains. On this basis corresponding changes are predicted for the Monster, Reindeer and Moose Channel Formations. Science, Faculty of Earth, Ocean and Atmospheric Sciences, Department of Graduate
|
|---|