Photic-zone euxinia and anoxic events in a Middle-Late Devonian shelfal sea of Panthalassan continental margin, NW Canada: Changing paradigm of Devonian ocean and sea level fluctuations

The latest Eifelian – Frasnian strata of the Mackenzie Valley, NW Canada, provide an excellent archive of paleoceanographic signals imprinted in oxic and anoxic facies deposited in close proximity. Fondoformic black-shale strata preserve fingerprints of four global anoxic events (Kačák, Frasnes, Middlesex, and Rhinestreet), which receives confirmation with δ13Corg data. The discovery of 2,3,6- and 3,4,5-trimethyl aryl isoprenoids (biomarkers of...