The petrology, organic geochemistry and palynology of Tertiary age Eureka Sound Group coals, Arctic Canada

Tertiary age lignites from Arctic Canada were analysed by petrographical, palynological and organic geochemical methods. Results from petrographic analyses indicate the predominance of wood-derived macerals (humotelinite group) in seams from the Strathcona and Stenkul Fiord areas, whereas in the Bache Peninsula area many seams are characterized by the predominance of detrital macerals (humodetrinite) and have also higher inertinite contents. Palynological assemblages are dominated by Taxodiaceae pollen, whereas Pinaceae pollen and pteridophyte spores are less common. Angiosperm derived pollen contents are quite variable. Organic geochemical results indicate that norisopimarane and pimarane are the most abundant diterpenoids. Cadalene was present in the aromatic fractions of all samples, with other components such as simonellite and retene in variable abundance. Rock-Eval data obtained from Stenkul Fiord area samples indicate low petroleum generation potential for this predominantly woody material. The depositional environment at Strathcona and Stenkul Fiords was that of a forested swamp, which formed in a lagoonal/alluvial plain setting. Palynomorph assemblages, petrographic indices and the abundance of diterpenoids suggest that the mire flora was dominated by gymnosperms, although locally angiosperms may also have been abundant as indicated by the occurrence of tetra- and pentacyclic aromatic hydrocarbons. At Bache Peninsula the mire was less forested as indicated by palynological assemblages typical for a marsh environment and petrographic characteristics such as low tissue preservation and the abundance of detrial macerals.