Palynology of Paleogene strata in the Caribou Hills, Beaufort-MacKenzie Basin, northern Canada

• Main Author: Parsons, Marion Grace
• Format: Thesis
• Language: English
• Published: 2000
• Subjects: Arctic; Canada; Caribou Hills; Banks Island; Foraminifera*; Mackenzie Basin
• Online Access: http://hdl.handle.net/1807/14405; http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ50053.pdf

grantor: University of Toronto Fluvio-deltaic processes deposited great thicknesses of Cenozoic sediment in the Beaufort-Mackenzie Basin. Caribou Hills outcrop strata afford a unique window on the shifting paleocommunities which flourished around some of the ancient Paleogene deltas. The Caribou Hills strata are predominantly delta plain sediments deposited under the influence of the active tectonic regime which characterized the Arctic during the Cenozoic. Palynomorphs preserved in these sediments record a mosaic of deltaic environments superimposed over time through the processes of local channel migration, delta lobe progradation, delta switching, subsidence and transgression. The resultant stacking of sedimentary facies is reflected palynologically in a rapid alternation between terrestrial and marine microfloras. These palynofloras are diverse, particularly the early Eocene floras. Intervals dominated by embryophyte spores and pollen are intercalated with others with high fungal or algal content. The algae are predominantly marine to brackish water species, but several are associated with extremely hyposaline or possibly freshwater habitats. These have particular significance since we know little about Paleogene dinoflagellates from very low salinity or freshwater environments. The strong environmental controls on palynofloral distribution dictated that an ecostratigraphic approach was essential for high resolution biostratigraphic and sequence stratigraphic analysis. To this end, informal interval zones were established for each palynomorph group; recurrent algal and fungal eco-groups were also distinguished. Embryophytes and fungi were of paramount importance for detailed regional biostratigraphic correlation, in particular, to the Adgo F-28 and Natsek E-56 wells, and the Banks Island sections. The algae, which are similar to those described from other marginal marine settings, were used to place time constraints on the zones. Fifteen new palynomorph species are described, and three new genera--'Ornatisporites' (fungal), 'Alamorpha' and 'Peregrinella' (algal). Palynostratigraphy, together with limited foraminiferal data, supports assigning the bulk of the Caribou Hills Tertiary strata to the late Paleocene-middle Eocene Aklak and Taglu depositional sequences. The age of an upper 'white clay' unit, separated from the Taglu sequence by an unconformity, remains unresolved but is tentatively assigned a late Eocene or Oligocene age; it is probably an equivalent of either the Richards or Kugmallit sequence. Ph.D.