Lower cretaceous terrestrial palynomorph biostratigraphy of the McMurray Formation, northeastern Alberta
LccQE 993 B849 1984
LcshPalynology - Alberta - Fort McMurray area
Paleontology - Cretaceous
Micropaleontology - Alberta - Fort McMurray area
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AbstractAbundant and diverse palynomorphs from the McMurray Formation of northeastern Alberta are examined and correlated with palynomorphs of the Ellerslie Member in central Alberta and Sunburst and Calcareous members of the lower part of the Kootenai Formation, near Great Falls, Montana. Three terrestrial palynomorph assemblage-zones and one Oppel-zone are recognized. In ascending order, the is overlain by the Impardecispora trioreticulosus-Fora~inisporis asymmetricus Oppel-zone , the Retimonocolpites crassatus-Kuylisporites lunaris Assemblage-zone and the Retimonocolp~tes peroreticulatus-Liliacidites inaegualis Assemblage-zone. Lower McNurray strata correlate biostratigraphically with Ellerslie and Sunburst strata of Alberta and Montana; Valanginian to early Barremian ages are inferred from palynology. Middle McMurray strata correlate with uppermost Ellerslie and Sunburst members, Calcareous member and an unnamed lignitic unit; Barremian through early Aptian ages are indicated. Upper McMurray strata of probable late Aptian to early Albian age are inferred to correlate with the Glauconite member of central Alberta and upper Kootenai Formation of Montana. Stratigraphy, sedimentology and biostratigraphy of the McMurray Formation and other Mannville Group strata from Alberta and Montana indicate two marine transgressions. The first culminated with deposition of the middle McMurray in northeastern Alberta and the Calcareous member in central Alberta and Montana. The second, resulting in deposition of the Clearwater Formation, is, in this study, only identified in northeastern Alberta. Common, statistically significant, palynomorphs are used to define 5 environmentally significant Acme-zones. The Cyathidites Acme-zone is inferred to be an upland flora. Cyathidites-Alisporites, Alisporites and Inaperturopollenites Acme-zones are inferred to come from lowland and coastal environments, whereas the Palaeoperidinium Acme-zone is an offshore marine assemblage. Palynomorph Acme-zones correspond closely with sedimentology. Hydraulic movement and sorting are believed to be the main environmental controls for Acme-zones in delta complexes. An illustrated systematic key, consisting of 118 genera and 233 species is developed for identification of Lower Cretaceous terrestrial palynomorphs from the Western Canada Basin.
Bibliography: p. 118-149.