Abstract On the European margin of the Tethys Ocean, late Cenomanian to early Turanian sea-level rises resulted in a progressive drowning of the Provence rudist-bearing platform, successive breaks in marine sedimentation, and the initiation of deep-water disaerobic conditions in the whole pelagic domain of the Vocontian Basin. Paleogeographic and structural features may have controlled the regional extent of oxygen-minimum layers, the distribution of laminated and organic-rich sediments, and the regional duration of such a worldwide Oceanic Anoxic Event. Sporadic modifications in the water stratification, perhaps due to climatic changes, induced high-frequency changes of the deep-water redox conditions. These changes probably caused short-term fluctuations in the thickness of the oxygen-minimum layers and the ecological perturbations recorded in the deep-water-dwelling planktonic and benthic biota. Periodic disaerobic conditions, which protected the sediments from oxidizing benthic activity, are thought to be the main cause of relative concentrations of hydrocarbon-rich amorphous organic matter found in these potential source rocks.