Abstract

Abundant and diverse palynomorphs from the McMurray Formation of northeastern Alberta are examined and correlated with palynomorphs of the Ellerslie and Calcareous Members of central Alberta and the lower part of the Kootenai Formation (Sunburst and Calcareous Members and an unnamed lignitic unit) near Great Falls, Montana.

Three terrestrial palynomorph assemblage-zones are recognized: in ascending order, the Trilobosporites canadensis - Triporoletes incertus Assemblage-zone, of Late Valanginian or Hauterivian age; the Impardecispora trioreticulosa - Foraminisporis asymmetricus Assemblage-zone, of Early Barremian age; and the Retimonocolpites crassatus - Retimonocolpites peroreticulatus Assemblage-zone, of Late Barremian through earliest Albian age.

Correlation of strata and assemblage-zones is hampered by complex cross-cutting relations. The juxtaposition of channel sandstones and shales containing different palynomorph assemblages precludes correlation of quartzose sediments more than a few hundred metres apart. The Calcareous Member may be easier to identify and correlate lithologically. However, from palynomorph biostratigraphy there is a hint of diachronism in these deposits and they may be slightly older in the south. Both the biostratigraphic and lithostratigraphic data-base must be improved before geologically consistent facies models of lower Mannville fluvial and deltaic deposits can be developed.