Stratigraphy and palynology of cretaceous and tertiary rocks, North Bylot trough, Bylot Island, Northwest Territories, Canada

Cretaceous and Tertiary strata of North Bylot Trough at Maud Bight on Lancaster Sound are divided into five formations representing three tectonic phases based on lithology and palynology. In detail, late Albian Hassel Formation fluvial quartz arenites were deposited at Maud Bight prior to rifting in Baffin Bay and Lancaster Sound (Phase 1). Late Campanian-mid Maastrichtian shelf mudstones (Bylot Island Formation) and mid to late Maastrichtian (Sermilik Formation) nearshore and beach deposited quartz arenites reflect uplift of the Byam Martin Mountains and separation from Eclipse Trough (Phase 2). Lower to middle Paleocene shale and thinly bedded sandstone (Navy Board Formation), lithic greywacke and over 200 metres of conglomerate (Aktineq Formation including the newly defined Maud Bight Member) are equivalent to strata in Eclipse Trough. The Navy Board Formation consists of braided stream, flood plain and lacustrine deposits. These strata are overlain by meandering stream deposits (Aktineq sandstone) and alluvial fan strata (Maud Bight Member). This tectonically deformed coarsening up sequence indicates renewed activity corresponding with the opening of Baffin Bay to the east and the Lancaster Aulacogen to the north (Phase 3). Based on spores, pollen and fungal remains three terrestrial palynomorph assemblage zones and one subzone containing components of both the Aquilapollenites and Normapolles Provinces are defined for the North Bylot Trough strata: Azonia cribrata-Aquilapollenites trialatus (AA) Zone, Porosipollenites porosus-Wodehouseia spinata (PW) Zone and the Paraalnipollenites alterniporus-Pesavis parva (PP) Zone. Subzone R lies within the AA Zone and consists of >85% recycled palynomorphs typical of mid to late Albian assemblages such as Cicatricosisporites, Tappanispora and Klukisporites. The AA Zone is late Campanian to mid Maastrichtian and is characterized by Azonia, Aquilapollenites, Trudopollis, Ceratiopsis and Lejeunia. Characteristic genera of the mid to late Maastrichtian PW Zone include Porosipollenites, Aquilapollenites, Beaupreaidites, Singularia and Wodehouseia. The PP Zone is early to mid Paleocene and is characterized by Paraalnipollenites, Trivestibulopollenites, Momipites, Triporopollenites, Caryapollenites and Pesavis. Organic matter recovered from strata at Maud Bight is thermally immature but with sufficient burial in offshore Lancaster Aulacogen would generate liquid and gas hydrocarbons. Stratigraphic relationships in North Bylot Trough, when applied with geophysical data in Lancaster Sound should allow for delineation of a series of stratigraphic and structural traps