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TitleA palynological analysis of middle Cretaceous strata in the Hume River section, Northwest Territories, Canada
AuthorFensome, R A
SourceGeological Survey of Canada, Open File 8073, 2016, 133 pages,
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS96B; 96C; 96D; 96E; 96F; 96G; 96J; 96K; 96L; 96M; 96N; 96O; 106
AreaHume River; Norman Wells; Mackenzie River
Lat/Long WENS-136.0000 -122.0000 68.0000 64.0000
Subjectspaleontology; stratigraphy; lithology; biostratigraphy; fossil assemblages; lithostratigraphy; palynostratigraphy; marine deposits; stratigraphic analyses; stratigraphic correlations; Martin House Formation; Arctic Red Formation; Slater River Formation; Trevor Formation; Mesozoic; Cretaceous
Illustrationsplates; stratigraphic columns; location maps
ProgramMackenzie Corridor, Shield to Selwyn, GEM2: Geo-mapping for Energy and Minerals
Released2016 10 06
AbstractThe Hume River section northwest of the town of Norman Wells, Northwest Territories consists of a 2-km-thick succession of Cretaceous strata deposited in a foreland basin ahead of the advancing Mackenzie Mountains thrust-and-fold belt. Rocks in the section have been assigned (from bottom to top) to the Martin House, Arctic Red, Slater River and Trevor formations. The Martin House Formation rest unconformably on Paleozoic strata, and an unconformity separates the Arctic Red and Slater River formations. In terms of paleoenvironments, the section represents fluctuating fully marine to non-marine deposits near the margin of the Western Interior Seaway. Previous age determinations have encompassed an Aptian to Turonian age range for the section as a whole. My analyses indicate an early to middle Albian age for the Martin House Formation, a middle to late Albian age for Arctic Red Formation (which accords with a late Albian U-Pb radiometric date for the unit), a late Albian age for the lowest part of the Slater River Formation (in contrast to Cenomanian age determined by the most recent foraminiferal analyses), and a Cenomanian or younger age for the upper part of the Slater River Formation and for the Trevor Formation. I found no conclusive evidence for an age younger than Cenomanian. The Albian-Cenomanian boundary may be within the basal part of the Slater River Formation rather than at the unconformity between that formation and the underlying Arctic Red Formation. Interesting parallels can be drawn with lithological units and dinocyst assemblages in other parts of the Western Interior Basin, notably in northern Alberta. Perhaps there too, the Albian-Cenomanian boundary is within the basal part of the Fish Scales Marker Bed (equivalent to the Slater River Formation) rather than at its base.
Summary(Plain Language Summary, not published)
The Hume River section northwest of Norman Wells, NWT, is a 2-km-thick succession of Cretaceous marine to non-marine strata in the Western Interior Basin. Previous age determinations based largely on foraminifera have encompassed an Aptian to Turonian age range for the section. My palynological analyses, especially the dinoflagellate cysts content, indicate that it ranges from an early to middle Albian age to probably Cenomanian, with the Albian¿Cenomanian boundary being a little higher than in some previous determinations. Accurate age determinations are important in unravelling the geological history of the region, and hence its petroleum systems. The section has also provided some well-preserved new fossil species that, when described in detail and searched for in other sections, may be additional important biostratigraphic tools, helping further to determine ages.