Late Cretaceous (Cenomanian to Campanian) Dinoflagellate Cyst Assemblages and Palaeoproductivity Signals from the Kanguk Formation, Sverdrup Basin, Nunavut, Canada

The response of the Polar Sea to Cretaceous carbon perturbations is poorly understood and palaeotemperature data from the Arctic are limited. To understand high latitude palaeoceanographic dynamics, dinocyst assemblages were collected from a composite Cenomanian to Campanian section from the Bastion Ridge and Kanguk formations within the Sverdrup Basin at Glacier Fiord, Axel Heiberg Island and Slidre Fiord, Ellesmere Island. Dinocyst assemblages were compared to carbon isotope and benthic foraminiferal age data indicating that age ranges for several Late Cretaceous dinocyst taxa need regional revision. At Glacier Fiord a turnover in dinocyst assemblages reveal a change from a brackish to marine palaeoenvironmental change before the onset of OAE 2. A correlation between δ13Corg, peridiniod dinoflagellate cysts and cooling global sea surface temperatures indicate an increase in palaeoproductivity during a Coniacian to Campanian cooling trend. Three dinocyst biozonations are proposed for the Sverdrup Basin.