An integrated chemostratigraphic and biostratigraphic framework and benthic foraminifera morphogroup response to paleoenvironmental conditions of the Upper Cretaceous Kanguk Formation, Canadian Arctic Archipelago

The Kanguk Formation, investigated at two localities on Ellesmere Island, Nunavut, Canada, is a unit of dominantly shales and siltstones deposited within the Sverdrup Basin that records the Late Cretaceous history of the Polar Sea. Two foraminiferal biostratigraphic zones with refined ages are proposed, the Turonian to late Santonian Evolutinella boundaryensis Zone and the late Santonian to Campanian Verneuilinoides bearpawensis – Glayphrammina spirocompressa Zone, which correlate to established zonations in the Arctic region. The carbon isotope record places the basal Kanguk boundary into the lower Turonian above the Oceanic Anoxic Event 2, confirming a younger age of this boundary towards the eastern basin margin. Benthic foraminiferal morphogroup assemblage changes are linked to global transgressive-regressive cycles and paleoredox conditions. Oxygen-limited, Trochammina-dominated assemblages or the complete loss of taxa characterize highstand intervals, due to enhanced primary production and an expanded oxygen minimum zone.