New Data on the Cenomanian–Turonian Boundary Oceanic Anoxic Event in the Biyuk-Karasu River Section (Central Crimea)

Abstract

Cenomanian–Turonian organic-rich clays deposited under periodic anoxic conditions in the basins of that time are recorded in carbonate sections. Cenomanian–Turonian boundary deposits were studied in the Biyuk-Karasu River section (Central Crimea). Dark organic-rich clays were found to intercalate with carbonate-poor clays in the formation during oceanic anoxic events. Mixed type II–III kerogens are abundant in these black beds which constitute oil source strata that are similar in their mineral assemblages but different in their organic matter contents.