Cenomanian to Santonian radiolarian biostratigraphy, carbon isotope stratigraphy and paleoenvironments of the Sverdrup Basin, Ellef Ringnes Island, Nunavut, Canada

摘要: Abstract An upper Albian to Santonian sedimentary record on Ellef Ringnes Island, Canadian Arctic Archipelago, records variable paleoenvironmental conditions within the Cretaceous Polar Sea and Sverdrup Basin. The lower Cenomanian uppermost Christopher Hassel formations represent a regressive system tract from offshore shoreface/terrestrial paleoenvironments. shales of Kanguk Formation signify distal basin setting controlled by increased subsidence high global sea levels. Siliceous pelagic faunas floras dominate herein, three informal radiolarian partial range zones are proposed for Sea. Alternating diversity abundance patterns interpreted as response sea-level productivity systems. Transgressive phases correspond low shallow dwelling taxa with an expanded oxygen minimum zone (OMZ); coupled radiations deeper species depressed OMZ. Turonian was marked preservation marine-type organic matter carbon isotope excursions indicate presence Oceanic Anoxic Event 2 (OAE 2) at base Formation. Rock Eval data suggest that increasing terrestrial influence prevailed during Coniacian Campanian time covering OAE 3. Benthic environments dominated anoxic conditions, suggested near lack benthic foraminifera extensive intervals fine platy shale lacking bioturbation. Only return dysoxic conditions. Radiolarian faunal comparisons more southern localities migration routes east through narrow North Atlantic pathway Pacific Alaskan–Asian Pathway.