Lac des Bois, a locality in the northern Western Interior Seaway (Canada) with Tethyan faunal connections during the Cenomanian/Turonian Thermal Maximum

• Published in: Cretaceous Research
• Main Authors: Cumbaa, S.L. (Stephen L.), Day, R. (Richard), Gingras, M. (Murray), Haggart, J.W. (James W.), Holmes, R.B. (Robert B.), Murray, A.M. (Alison M.), Schroder-Adams, C. (Claudia)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Acanthomorpha; Ammonites; Cenomanian–Turonian boundary; Inoceramidae; Northwest Territories; Arctic; Canada; Lac des Bois; Foraminifera*; sverdrup basin
• Online Access: https://ir.library.carleton.ca/pub/20430; https://doi.org/10.1016/j.cretres.2018.07.012

Early Turonian fishes are known from only a few localities in the Northern Hemisphere, including three in the present-day European/Mediterranean region and three in northern Canada. One of the latter localities, Lac des Bois (66°52.087ʹ N), preserves a diverse marine fauna composed of trace fossils, foraminifera, molluscs and actinopterygian fishes including early acanthomorphs. The molluscan fauna, as well as a radiometric date from bentonites recovered from the site, support an age of latest Cenomanian/early Turonian for the locality. This interval spans the global Oceanic Anoxic Event 2, a time characterized globally by high temperatures and high carbon burial. Although the Cenomanian/Turonian boundary interval has been documented in North America in the Arctic Sverdrup Basin and the southern Interior Seaway, the present study provides the first account of a faunal assemblage that inhabited the northern Western Interior Seaway during this interval. Organic-rich shales and sandstones indicate limited organic decomposition and low oxygen conditions, alth